Seacocks, Strainers & Hose Clamps – Marine How To

PVC Below Waterline? Please Don’t..

Rod Collins — Wed, 30 Aug 2017 16:03:48 +0000

Oh Fu¢k..!!!!

I know many boat builders often used improper seacocks, eg; a ball valve threaded directly to on a thru-hull fitting as well as seacocks not meeting the ABYC standards for strength, materials, thread compatibility etc., but really folks, Schedule 40 PVC has no place being used below the waterline on your vessel. A failure of this Schedule 40 PVC adapter almost sank this boat.

In mid June I got a panic call from a transient boater who was stuck in Falmouth, ME after having sailed here from Massachusetts. Apparently, somewhere off the Isle of Shoals NH, the owners wife went below to open the overboard discharge, 3 miles off shore, in order to drain their full holding tank. This led to a bad chain of events all due to sub standard & non ABYC complaint boat building practices.

Due to the very poor location & orientation of the seacock, by the builder, to open it required a bit of forearm bracing on the hose/male adapter for leverage. The installed location also required the operator to be a borderline contortionist.. Let me stop right here and point out that this boat was not built to ABYC safety standards in this regard:

ABYC H-27 “27.6.2 Seacocks shall be readily accessible as installed, and so oriented that their handles are easy to operate.”

When the owners wife braced her forearm, and lifted the handle, she heard a funny noise. With the seacock now about half open she again braced and lifted, only this time she was met with a face full of seawater and holding tank contents… D’oh……

This particular 1 1/2″ valve, for direct overboard discharge, did not get used or exercised much, as a result it had become quite stiff or far stiffer than it should be. The effects of holding tank contents, including uric acid, on a valves ball can lead to surface pitting & corrosion and can cause them to become quite stiff. All seacocks should be cycled or exercised regularly in order to help minimize this. By cycling the ball regularly it “wipes” the balls surface on the valve seats before permanent adhesion can take place. Regularly cycling or exercising your seacocks is one of the best things you can do for them to keep them in smooth operational order.

When the owners wife got doused in the face with seawater she initially had no idea what had happened, but quickly realized they had a 1 1/2″ diameter hole in the boat well in excess of 3 miles from the nearest land. She screamed in such a panicked tone her husband literally dove below so fast he missed the companionway all together. He nearly broke his arm doing so. With some moves a Yoga instructor would be proud of, in the midst of geyser in full flow, he was finally able to get the valve mostly closed. With less water flow and a calmer mind he performed a few more open/close cycles, with faces full of water each time, the valve was able to be closed. Once the valve was closed they energized the bilge pumps and began the clean up process.

According to the owner, his wife then began violently throwing up due to the stench of the holding tank contents that were now mixed with what the owner estimates as about 35 -50 gallons of “shitty water“…. Not really what I would define as a fun trip to Maine to begin your cruise.

150% Unacceptable & Totally Unavoidable

I hear it over and over from owners about how they choose to leave seacocks open, when the boat is unattended, because they are just too hard to access. This is simply bad form on the part of the builder and not ABYC complaint.

This seacock was quite stiff, poorly located and was installed with sub-standard non-compliant PVC fittings. The mere bracing of a forearm on the male adapter & 1 1/2″ sanitation hose, while trying to open this seacock, causes the Schedule 40 PVC to fail. This is 150% unacceptable and completely avoidable, had the safety standards been adhered to when the builder constructed this vessel. When thinking about this situation, on-top of the PVC failure, think:

What if the seacock could not have been closed once partially opened?
What if this occurred in rough seas?
What if the handle stripped the shaft when partially open?
Are you actually prepared to deal with an event like this?
Are you willing to accept a boat filled with 35-50 gallons of “shit water”?

If the answer to any of these questions is no, then please ensure your vessels seacocks are installed and constructed to meet the bare minimum safety standards. It may just save your vessel or your life.

This owner actually thought he was prepared, but he soon realized that his soft-wood tapered safety plugs, the ones we all have aboard, would not fit into the seacock with a partially closed ball.. Oops…

This scenario is something I had actually not considered either, but it sure suggests that a hand saw should also be on-board to trim a plug to the correct depth if needed. While I do carry a hack saw on-board, and it could work, it would be extremely slow due to the ultra fine teeth of a metal cutting hack saw. The point here is to consider every failure point & scenario in a seacock assembly and be prepared for it ahead of time.

ABYC Seacock Strength Requirements

The ABYC standards are very clear on the testing requirements for installed seacocks yet numerous builders over the years, including many current production boats, blatantly ignore these requirements. The builder of this boat completely ignored the bare minimum ABYC safety standards adn this boat was built by a builder who was an ABYC member/builder.

The ABYC/UL strength test is performed at the innermost part of an installed seacock, usually the male hose adapter, innermost portion of an elbow or the innermost portion of the assembled seacock. The test requires the seacock assembly withstand a 500 pound static load for at least 30 seconds and not allow any ingress of water.

“27.6 INSTALLATION

27.6.1 A seacock shall be securely mounted so that the assembly will withstand a 500 pound (227 Kg) static force applied for 30 seconds to the inboard end of the assembly, without the assembly failing to stop the ingress of water (see Figure 1).”

The European ISO/RCD standards are slightly different than ABYC requiring 337 pounds of force at a position of 20 mm inboard from the internal end of the fitted seacock. This 337 pounds of force is cycled 10 times. The seacock is then tested to 1 Bar of pressure and can not allow any water to leak in and must operate as intended.

Regardless for which standard you choose, a fore arm merely bracing against the hose, while opening a seacock handle, is a gross failure to adhere to either standards and to construct a safe vessel. This should have been installed correctly by the builder but it also should have been noted by the owners insurance surveyor, neither of which occurred. This boat was built during a time period all these ABYC requirements were in place so there was no excuse for this level of cheap-skateism..

Just for grins I tried to press my forearm against my load cell, in order to see how much pressure I could deliver. Suffice it to say I was not even in the ball park, let alone the league, and my arm hurt for a solid week.

There are only a few seacock materials that should really be used below the waterline and those are:

Marine Bronze – In the US this is usually manufactured from an 85-5-5-5 metallurgy. An 85-three-five bronze alloy is roughly; 85% Copper, 5% tin, 5% lead and 5% Zinc. Reputable manufacturers of 85-5-5-5 bronze seacocks and adapters include; Apollo/Conbraco, Groco, Buck Algonquin, Perko & Spartan Bronze. Any Bronze seacock, thru-hull, elbow, male adapter etc. should wear the marine UL labeling and be 100% galvanically compatible with what it is mated to. Mixing dissimilar metals below the waterline is a recipe for disaster.

Forespar® “93” series Marelon – Marelon is a glass reinforced nylon product by Forespar. *Only the OEM / “93” Series Seacocks have been tested to ABYC strength requirements.

TruDesign Plastics – TruDesign is another glass reinforced nylon product that meets the ABYC strength requirements in most sizes.

Please, please, please take your seacocks and below waterline fittings seriously:

Inspect them regularly
Cycle them regularly
Locate them for easy access
Use marine rated hose intended for below water-line applications
Use flanged seacocks
Use non-perforated 316SS hose clamps from either ABA or AWAB
Make sure your male adapter is long enough to accept two hose clamps
Do use galvanically compatible materials
Do use Marelon, 85-5-5-5 Marine bronze or TruDesign Seacocks
Do not use PVC
Do not use yellow brass fittings
Always ensure threads are compatible

For more information on seacocks see the other MarineHowTo.com articles below:

Seacocks Strainers & Hose Clamps

Good luck & happy boating!

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Seacock Backing Plates

Rod Collins — Wed, 04 Mar 2015 03:26:42 +0000

Start by Drilling a Hole

Many readers have asked me how to install stronger, flanged seacocks without also drilling extra holes in your hull for the bolts that hold the flange. It can be done, as you will see below.

Though this method is going to be slightly less robust, than through bolting, I would have no qualms about using this method on my own boat. I do admittedly through bolt on my own vessel but this is out of personal preference.

Don’t get me wrong this is still a very robust installation, if done with care & patience, and it is stronger than the hundreds of thousands of vessels out there with noting more than a valve threaded to a thru-hull.

This is also a good option for those owners with cored hulls, where thin external skins are to thin to take the countersink depth of the bolt head.

This article already assumes you’re using GPO-3 polyester/fiberglass or G-10 epoxy/fiberglass sheet for the backer blocks, and have already made the circle/donut. It also assumes you are utterly opposed to through-bolting your seacocks to the hull or physically can’t due to external skin thickness on a cored hull..

For tapping the backers I recommend a thickness of about 5/8″ for your GPO-3 or G-10. In testing I have exceeded 1000 pounds of direct pull on 1/2″ home made polyester fiberglass board. G-10 and GPO-3 are far stronger than my home made fiberglass sheet and the extra thickness yields even more strength. In testing with G-10 just one single 5/16″ X 18 thread bolt, drilled & tapped into 1/2″ G-10 far exceeds the ABYC strength requirements for seacocks..

Unlike the other method, where you glass the backing plate to the hull first then drill the hole for the thru-hull, with this method you drill the thru-hull hole first. To do this project a drill press is strongly recommended.

A Perfectly Centered Hole

By using the pilot hole you made the original circle with you will automatically have a perfectly centered hole in the backing plate.

Be sure to use a hole saw as close to the OD size of the thru-hull as is humanly possible. There should be very little room between the threads and the fiberglass.

Please be aware that working with G-10 or even GPO-3 board is like working with steel. It eats & dulls tools for lunch.

Make A Shim

Before you drill and tap the backer block you need to tighten the flanged adapter to the backing block using the thru-hull. Because you’re missing the thickness of the hull you will need to create a spacer that takes the hulls place.

I used some PVC exterior trim lumber and drilled the same diameter hole as in the backing block. Then all I did was center & tighten the flange and thru-hull together with the backing plate and hull thickness dummy spacer sandwiched in between.

Clamp & Drill

This is the most critical step and why you really should be using a drill press. Because you are literally drilling and tapping a piece of 5/8″ fiberglass or epoxy sheet, the threaded holes must be perfectly centered in the flange holes, and they must be 100% vertical or a perfect 90 degrees to the backing block..

I made my dummy spacer square, and wider than the head of the thru-hull, so I was able to clamp it in my drill press vice. I can not stress enough how important it is to make perfectly vertical holes that are perfectly centered in the holes of the flange or seacock. There is absolutely no wiggle room here. Mess this up and you just wrecked the backing block..

Drill & Tap

Please don’t cut corners on the quality of your tap and always use the proper size drill for the tap you are using.

This is an “F” drill for a 5/16″ X 18 thread tap. You could also use a 17/64″ drill with a 5/16″ tap.

IMPORTANT: Fiberglass or epoxy sheet is susceptible to off-center tapping so be careful to not work your tap crooked or wobble your tap side to side. It will make the tapped hole bigger than you want. Practice in a scrap piece of fiberglass first if your not comfortable with this.

Once tapped through use an air gun to blow the flutes of the tap out. Do this before reversing it out of the fiberglass.

Tapping The Backing Plate

This is fairly straight forward but remember to tap this perfectly straight. Avoid over tapping, multiple tries or passes. Each pass will remove more material, once in, once out.

Cutting The Studs

Silicon bronze threaded rod is expensive but silicon bronze carriage bolts are cheap. Simply install two nuts onto the bolt and clamp only one of the nuts in the vice while tightening the other back onto it. This essentially locks the bolt into the vice so you can cut it without it spinning or moving.

Why Studs?

IMPORTANT: The reasons for using studs or even epoxy captured nuts, if the backer is thick enough, is for future removal. During removal the studs or bolts into epoxy inset nuts can be removed fully and the seacock can be peeled off with a guitar string or pried at an angle without the studs interfering. With fully captured non-removable bolts, it makes future removal and nightmare project.

Picture yourself trying to remove a seacock in the future with three captive bolts and you can’t get under it with a guitar string or to even rock it back and forth due to the studs being permanently in place. You can also accidentally mar, gall or damage the threads and then the bolt snaps or strips out and begins spinning in the substrate with no way to fix it other than MAJOR surgery. The reasons for drilling and tapping for a stud or burying a bronze nut in the plate, are more about the future and less about the now.

Cut Off Wheel

Though this 1 1/2″ Dremel cut-off disc says “Plastic” it is my favorite tool for cutting bolts or threaded rod, and it works equally well on stainless or bronze.

Cut Off The Head

As you get good with the Dremel you can make some amazing bolt cuts with threads that work as good as factory. Of course you could use a hack saw too but the Dremel is nice & fast. Always chase the fresh cut with a thread die.

Finish The Threads

Once I have cut the bolt I then clean the cut end on my bench grinder with a brass wire wheel. This one looks almost as good as the factory end and performs the same too.

Insert Studs

With the studs made you simply thread them into the backing block. If you got a little aggressive with the tap it’s not the end of the world. Mix up some slightly thickened epoxy and apply with a syringe into the hole, wax the stud and thread it in with the thickened epoxy and let it cure. This will create a nearly perfect thread interface between the stud and backing plate. Even with a good tap I still dip the stud into epoxy, coat the inside of the hole and thread it in.

IMPORTANT: If using the epoxy trick I just mentioned please wax the stud well or you won’t get it back out once the epoxy has cured.

Install Flange or Seacock

Once the studs are in simply drop the flange over it put on the nuts. You’re now ready for a dry test fit in the hull.

Side View

This photo shows a side view of the assembly. The hull & sealant are the only pieces missing.

Bottom View

Here you can see the bottoms of the drilled & tapped studs.

Don’t Forget to De-Wax

You’ll want to de-wax the backing plate. Polyester finishing resin has added paraffin to aid in the cure process and this won’t yield a good secondary bond if the wax has not been removed. This wax, and the wax coating from what you laid it up on, id not using GPO-3 or G-10, must be removed prior to installation or nothing will adhere well.

Over the years I have found the dedicated, but overly priced, cocktails of chemicals sold by Pettit or Interlux as de-waxers definitely do work. I only wish I could figure out what the chemical mix is because I bet I could mix it up for considerably less than what they sell it for.

Aggressively Sand

For good adhesion you really need a clean surface with nice deep scars and surface irregularities. For this I use a Fein Multi-Master and the Carbide Triangular Rasp attachment. This is a hard, carbide tipped sanding attachment. It produces about 5 times the sanding performance of 40-grit paper, but won’t load up with residue. It also LASTS for a long time, years actually, because it’s carbide.

If you don’t have a Fein, or other multi-tool, don’t worry as about any wire wheel brush on a drill will do a similar job or 36 grit discs on an angle grinder..

Sand The Hull

Before you begin sanding the hull you should remove any surface wax. Gelcoat, like polyester finishing resin, is also an air inhibited cure so any gelcoat on the interior of a hull has a waxy surface. In order for proper adhesion any interior gelcoat needs to be removed.

This are still needs a bit of sanding to get rid of the rest of the gelcoat.

Dry Fit

In order for your backing block and through hull to fit properly you really need to perform a full dry test fit. It took about four tries to get the thru-hull to sit flush on the exterior of the hull due to some irregularities on the interior that needed to be sanded out.

IMPORTANT: The two planes, internal and external, must be parallel under both the backing block and the thru-hull head for a proper fit and this can take some considerable fitting, sanding & grinding.

Installation

Once your dry fit is confirmed parallel, and all sides of the thru-hull head sit flush, on the hulls exterior, you will need to do one more round of de-waxing of both hull and backing block.

After that is done you need to wax both the flange (not the backer block) and the thru-hull fitting with copious amounts of mold release wax, butchers wax or even Collinite. The wax should be a paste type carnuba.

After you have waxed it cut a scrap board to length and wedge the thru-hull into place. If you are on gravel or dirt lay a board on the ground to wedge the upright board against.

Contrary to popular belief you really do not need two people to install a thru-hull, especially if you can be a little creative.

View From Inside

Here is the waxed thru-hull ready for the resin mix, backing block and flange.

Mix Your Resin

For illustration I choose to make a formula to show the consistency better. Whether epoxy, polyester or vinylester all should be plenty strong for this application. Epoxy is considerably stronger than polyester resin, in a secondary bond, and is what I personally use.

My mix for illustration consisted of chopped strand fibers, West System 406 Coloidal silica or Cabosil, some West 404 and polyester resin. The same mix can be made with epoxy. When I shot this I was not ready to lay it up so used the less expensive polyester resin because it was going to waste anyway.

I like making my own “cocktail” of putty because it gives me more control over consistency and how it fills & fillets. Kitty hair is another product I sometimes use but it will not fillet as well as your own custom mix will.

For a catalyst in the illustration I used some red dyed MEK-P. I like dyed MEK-P so you know you have it thoroughly mixed.

Wear rubber gloves and apply a thin coat of the mix to both the hull and backing block, then slather a large amount onto the backing block and thread it onto the thru-hull about three threads. I then used vise grips to grip the flange to prevent it from spinning and went out side the boat and used my step wrench to tighten down the thru-hull and seat the backing block.

Note: Epoxy will yield a much stronger bond than polyester resin but even polyester should give you about 500 PSI adhesion. ABYC standards call for the seacock to support a 500 pound static load for 30 seconds at the inner most hard fitting or hose barb. Remember that 500 PSI is per square inch. Your backing block is considerably larger than 1 square inch…

Installed

Here is the tapped fiberglass backing block installed and ready for curing. Let it cure overnight and in the morning go remove the thru-hull, and the flange, then clean them of the wax.

The last step after de-waxing the thru-hull and flange is to bed them with underwater rated marine sealant and install the seacock, hose barb and hose.

You now have a life long backing block, with replaceable studs, and no extra holes in your hull. Simple and easy to do.

Good luck & happy boating!

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Rebuilding A Perko Bronze Sea Strainer

Rod Collins — Wed, 04 Mar 2015 03:25:15 +0000

All The Pieces

In Maine we get long winters, and it gives us plenty of time to do projects, projects many owners, in other parts of the country, may put off until a failure point is reached. The lowly sea strainer is one of those devices no one ever thinks to rebuild, repair or replace, but they should.

For years I have used these solid cast bronze sea strainers from Perko. I also use & install the bronze strainers made by Groco. Unlike some Perko products this particular item is very well designed, hefty and will last a lifetime with only the occasional rebuild consisting of three gaskets. I find it to be one of if not the best built strainers on the market today and have gone to the trouble of installing them on almost every boat I have personally owned and on customers boats where and when the owners budget allowed for it. Fortunately this boat came with one already installed.

For this project I wanted to clean all the bronze pieces, polish the sight-glass and replace all three gaskets. For cleaning I used a stainless wire wheel brush in my bench grinder. The stainless wire wheel I use most often is made by Weiler. I also utilized my drill press with wire wheels and Scotch-Brite wheels on my Dremel tool. For polishing the sight-glass I used Novus #2 & Novus #1, but any clear plastic polish will work.

Here you can see all the pieces disassembled and a new gasket kit, which is readily available from Hamilton Marine in Portland, ME.

Old Elbows & Hose Barbs

When we bought our current boat I was ecstatic that it already had a bronze 1″ Perko strainer but not so thrilled with the configuration of the elbows. During this rebuild I took the opportunity to replace them with proper one piece bronze sweeping elbows. I prefer as few threaded fittings in my system as possible and with this one upgrade I lost two.

Sweeping elbows, these are gradual turning 90’s, also allow more eel grass and weed into the strainer without clogs occurring before the strainer basket.

Teflon Tape & Pipe Dope

This is one of the new sweeping bronze elbows. I like them for two reasons.

1- They are smooth walled and have a smooth radius bend. Because of this a snake can be run down through them to clear out an intake hose that has become clogged with weeds.

2- I lose an entire threaded connection.

In this photo I have wrapped the threads with Teflon tape, and before insertion, I also coated the Teflon tape with Hercules Real-Tuff pipe dope. Good pipe fitters very often use both tape and dope together. I learned this in my early 20’s when I was a manufacturers rep in the hydronics industry actually selling to wholesale distributors a product line which included Teflon tape and pipe dopes.

Tape + Pipe Dope

Here the sweeping bronze elbow is ready to be installed.

Install Compression Rods

I didn’t photograph taking it apart but you do get the benefit of seeing how to put it all back together.

IMPORTANT: If your compression rods are showing any signs of corrosion or wasting replace them!

The first step is to install the four compression rods. Simply thread them into the base casting finger tight. To snug them up use two of the nuts tightened against each other, with a washer in-between. Tighten the nuts on the top threads. Put a wrench on the top nut and take about a half to quarter turn beyond finger tight. You don’t need to over tighten them just snug them up a little.

Instal Bottom Gasket

Before installing this gasket I had pre-cleaned the surface. To install the gasket simply set it into the base casting. The slot in the gasket material should be face-up to accept the sight-glass cylinder.

Install Sight Glass

To install the sight-glass cylinder simply set it into the slot in the gasket. Be careful and be sure the sight-glass has not bent or deformed the gasket in any manner before proceeding to the next step..

Install Top Gasket

Installing the top gasket is as simple as installing the bottom gasket and again the slotted side of the gasket faces the sight-glass cylinder.

Install Top Casting

To install the top casting simply place it over the compression rods and set it into place. You may need to align the rods slightly, with your fingers, before it will drop into place.

Flip the strainer over and check the gasket before proceeding to ensure it’s properly seated in the top casting as well as around the sight-glass cylinder.

Install Nuts & Washers

This is just as easy as it sounds. Simply drop the washer into place then make all four nuts finger tight. Once they are all finger tight use a cross-torquing pattern, like you would use on lug nuts, to tighten and compress the strainer and gaskets.

Torque each nut evenly and just a little at a time, but do not over tighten. The nuts do not need to be cranked down, just tight enough to compress the gaskets and make a water tight seal. Again, torque the nuts evenly in a cross or star pattern similar to tightening lug nuts on a car.

Incorrect Orientation of Strainer Basket

My one and only complaint about this strainer is that the strainer basket can be inserted incorrectly.

In this orientation the handle of the strainer basket blocks and catches any weeds coming through the hose.

Leaving it this way, and closing the lid, can cause a back up in the elbow or inlet instead of letting the weeds pass to the internal strainer basket as it is designed to do.

If you look closely you can see how the inlet hole is blocked by the basket handle. This orientation is a no, no..

Correct Orientation of Strainer Basket Handle

In this photo any debris getting sucked it will flow into the basket and will not be blocked by the handle of the strainer. This is the correct orientation for the strainer basket handle to be in before closing the lid.

Install Cap Gasket

The last step is to insert the new cap gasket into the cap. Simple as it gets…

The Completed Project

This is the cleaned & rebuilt Perko strainer ready to be re-installed in the boat. Even with the cleaning and polishing of the sight glass, and the installation of the new elbows, this project took less than 2 hours.

Good luck & happy boating!

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Proper Installation Of Double Hose Clamps

Rod Collins — Wed, 04 Mar 2015 03:18:52 +0000

Male Adapter Too Short

Quite often when working on boats I notice or see odd fitting hoses. It doesn’t take much to figure out why once you start paying attention. Many, if not most generic non-marine male hose adapters are not built, designed or ever intended for marine applications where the use of two hose clamps, for below waterline applications, is preferred for safety.

When the male adapter is too short, tightening down a second hose clamp can actually distort the hose, create a potential for it to rip or tear and it can actually work against the hose adapter by trying to “pinch” the hose off the end.

If the first clamp were to fail, as they can and do, the second clamp could potentially have enough pressure on it to aid the hose in coming off the hose adapter.

This nylon hose adapter is far to short to accept two hose clamps. Always measure the exposed barb surface before installing two hose clamps.

Correct Length Male Adapters

These are marine bronze male adapters, one made by Apollo/Conbraco and one made by Groco. Note the length of the hose adapter portion. There is plenty of space to fit two hose clamps and this is exactly what you will want.

It should go without saying that hose adapters, for below waterline use, need to be marine bronze, Marelon or otherwise UL or ABYC complaint. Materials used need to also be galvanically compatible (A UL requirement for below water fittings). They should not be made from yellow brass or PVC. While home center yellow brass may be fine for the domestic plumbing aboard, or even some fuel fittings, it is not suitable for use below the waterline.

Always make sure your hose adapters will fit two hose clamps..

Measure

When it doubt measure what you have..

Compare

Now compare your measurement with the actual male adapters length. This one is fine but is cutting it very close. It’s really bordering on too short despite being made of marine bronze. This bronze male adapter was made by Perko and Perko pretty much dropped the ball on this one.

Incorrectly Clamped

Double hose clamps won’t do any good, and can actually be detrimental, if they are not clamping anything but air.

Please be sure your hose clamps are clamping what they are intended to clamp.

Low Quality Perforated Clamps

The other half of this equation is to always use good quality 100% Stainless steel hose clamps. Here at Compass Marine we use only AWAB or ABA brand non-perforated hose clamps.

These days there are far too many substandard perforated hose clamps on the market just waiting to sink your boat. Even clamps marked as “all stainless” are often not “all stainless” or the stainless or no-name imported mystery metal is anything but all stainless. With off shore sourcing & heavy price competition it has become hard to know what constitutes a good quality perforated clamp vs. the plethora of junk that may compromise the above water stature of your boat.

This is one of those suspect clamps I referenced above. It was marked, as you probably guessed, “all stainless“. I suspect it might be “stainless” if you stored it in the Tupperware container, with a bag of Damp Rid, and stuck in the the Mojave dessert with 12% relative humidity. On a boat, in the actual ocean, it certainly was not “stainless” at all.

We used to keep a bucket of failed perforated hose clamps to show customers, this was just one of them. The issue of low quality hose clamps has become so bad that we will no longer install perforated hose clamps for below water applications. Do yourself a favor and request AWAB or ABA branded non-perforated hose clamps for your below waterline applications.

AWAB Non-Perforated vs. Perforated Clamp

Our clamps of choice these days are made by ABA or AWAB of 100% 316 SS. The clamp pictured on top is an AWAB brand clamp. The quality is excellent & we have never once been able to strip one or seen one fail. We can’t say the same for perforated hose clamps. For below waterline hoses, 1/2″ ID and larger, they are an excellent choice.

There are also plenty of knock offs to the ABA or AWAB clamps but they are not all created the same. The ABA or AWAB quality is consistent and has proven to us, time and again, the value in in using them.

Typical Perforated Clamp Failure Mode

This is just one of many perforated clamp failures we’ve come across, and one reason I no longer trust my own vessel, or customers vessels, to them. This clamp was a single clamp, not one of two as it really should have been. It was installed on a galley sink drain. The hose was weeping because the single clamp had “slipped” and let go. If that hose had fallen off the male adapter, the boat would have sunk. One of our guys caught this just in-time.

To recap, please make sure the hose adapter is long enough, use two clamps for below waterline applications and consider using a higher quality non-perforated clamp such as those made by ABA or AWAB.

Perforated Hose Clamps = FAIL!

Just in case you needed more reason to STOP USING perforated hose clamps here are some complete failures we’ve found on-board some of the boats we work on.

All of these perforated clamp failures were from BELOW WATER fittings and three of them were the ONLY CLAMP……! Ouch! Yes, leaks were happening.

Good luck & happy boating!

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Installing A Seacock In A New Location

Rod Collins — Wed, 04 Mar 2015 03:16:28 +0000

Choose the Location

This photo is showing the spot for the new seacock & thru-hull as chosen from inside the vessel. Care should be taken when considering anew location for an additional seacock which includes, easy access, hose routing and seacock location for valve movement..

Once you have chosen your new location drill through the hull from inside using a 1/4″ drill bit. The reason for the 1/4″ bit is that it matches the size bit used on most hole saws.

You then drill into the hull from outside using the proper sized hole saw to match the thru-hull.Be very careful to drill perpendicular to the hull or the thru-hull fitting will not fit flush.

TIP: Start the hole saw in reverse, as I have done here, and you’ll greatly minimize or remove the possibily gelcoat chipping. Once the hole saw is through the gelcoat, switch to forward and drill up through the hull making sure you are perpendicular to it.

Tape, Knife & Thru-Hull

The next step is to tape off the hull and then use an X-Acto knife, or similar, to cut out a hole in the tape.

Tape The Hull & Cut The Hole

The hull has been taped off and the hole cut out cleanly with the X-Acto knife.

Sand Away Bottom Paint

With a hole cut in the tape press the thru-hull tightly into the hull and lightly trace it with the X-Acto knife, just enough to cut the tape, then peel away the tape that was under the thu-hulls head.

Once the ring of tape has been pulled off sand away the bottom paint that would be under the thru-hull. Sand until you get to gelcoat or a barrier coat as shown here. This will create the best watertight seal between the hull & thru-hull fitting.

Install Your Backing Block

Install your backing block following the instructions in my other articles on seacocks. Here the backing block, and Groco flanged adapter are shown epoxied, bolted & sealed into the hull with Sikaflex 291 and ready for the bronze thru-hull to be threaded into it from outside.

Goop The Thru-Hull

With the seacock or flanged adapter already installed and bedded to the backing plate, lather up the thru-hull fitting with a marine sealant of your choosing. For this installation I used Sikaflex 291.

The beveled mushroom head of the thru-hull fitting is what creates the water tight seal against the hull, and is the most important place to put sealant. Putting some sealant on the threads is only a secondary measure and adds some thread lubrication when tightening it down.

Install the Thru-Hull

The thru-hull fitting is now threaded into the seacock or, in this case, the flanged adapter. It’s important to dry test fit everything first to make sure you’ve cut the thru-hull to the proper length and that everything fits perfectly. Do a dry run before applying the marine sealant.

Tighten & Torque the Thru-Hull

In this photo the thru-hull has been fully tightened using a thru-hull step wrench and a large wrench. I torque it down fairly well into the seacock.

At this point it’s time to thread the bronze Marine UL ball valve onto the flanged adapter. For this you coat the male thread of the flanged adapter with a plumbers pipe dope. I use Hercules Real-Tuff a my pipe dope of choice.

Clean Up & You’re Done

Once the thru-hull is torqued down clean up the excess sealant and then remove the tape. This job is pretty easy and by using the tape method you don’t impact the bottom paint more than is absolutely necessary for the installation.

Good luck & happy boating!

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Freshwater System Winterizing

Rod Collins — Wed, 04 Mar 2015 03:16:08 +0000

What Not To Use

For winterizing your fresh water system you will need a few items. The number one item to have is RV type propylene glycol antifreeze that is safe for domestic plumbing systems. Unfortunately, I see this type of alcohol based RV type product all too often.

The pictured bottle is not a propylene glycol product, it is an alcohol based antifreeze. Alcohol based products can damage certain plastics and seals. While it is cheap, please don’t be tempted by price and please do read the labels.

WARNING: Do not use ethylene glycol that’s designed for use in automotive engines. It’s poisonousto mammals/humans! Propylene glycol usually comes in windshield washer type bottles and ethylene glycol generally comes in Prestone or Peak type bottles.

Using the method outlined below the RV type antifreeze is sucked through the system pipes only, and the tanks are left dry and drained with no antifreeze to purge in the spring.

You will also want a section of hose and the associated fittings to bypass your hot water heater so it too has no antifreeze in it for spring purging.

Some other items to consider would be a five gallon bucket, turkey baster, screw driver and some spare hose of the same diameter as your plumbing system.

“RC why don’t you just blow the lines out with air”

While this technique may work on some boats it does not successfully work on all boats. Also most boat owners generally don’t have large enough portable compressors to facilitate doing so. The Maine based boat yards I frequently do work in winterize hundreds of boats and they blow out none of them. Almost every every boat has antifreeze sucked through the pipes because it is far more reliable.

COMBUSTIBLE…???

TIP: If the RV antifreeze says “WARNING:COMBUSTIBLE” walk away. A propylene glycol product is not flammable but one made with ethyl alcohol is. This cheap product is a blend of ethyl alcohol and PG. Choose a product that does not contain alcohol.

When in doubt always read the labels. Do not be tempted by price. Ethyl alcohol blends can be had for as little as $1.99 to $2.99 per gallons while a typical price on a propylene glycol -50F rated product is about $4.50 – $5.50 per gallon..

A Better Product

Here’s a shot of a better true propylene glycol antifreeze product that is safe for most plumbing parts. It also has a decent corrosion inhibitor. It’s safe for engines and domestic plumbing systems. It has no alcohol in it.

The Refractometer:

The item in front is a called a sight refractometer. This is the tool I use to test the concentration of the propylene glycol, that has been sucked into the system, in order to determine when I have pumped enough through the system to adequately protect it. Samples are taken at each faucet, shower head and wash-down spigot etc. and tested for concentration strength..

Star-Brite Aintigel -50 is also an excellent -50F antifreeze. If you’re in an area that gets really cold, less than -25F, then you may want to consider a -100F rated propylene glycol.

The Water System Manifold

Step 1 – Drain Tanks:

In this photo I’ve drained the port and starboard water tanks, by using the fresh water pump, & then disconnected the tank outlets from the supply manifold. This manifold uses PEX & “Shark Bite” brand PEX tube fittings. They disconnect easily so they can drain into the bilge compartment, naturally & through gravity, with the rocking motion of the boat.

This photo was taken after only a few hours and it was almost totally drip free and dry at this point. This means both tanks have virtually zero water in them and the tanks will get no antifreeze.. I prefer not to put any antifreeze into tanks because it is a bear to get out through the process of dilution in the spring.

I’m rather uptight about keeping a dry bilge, mold allergies, that’s why you’ll notice a rubber stopper in the limber hole to keep the water contained in that compartment.

NOTE: Not all boats lend themselves to the tanks being drained fully via the 12V water pump. In these situations I use a 12V pump and rags to empty the tanks from above, if there is a clean out port. If there is no way to get into the tank then the only option may be to add antifreeze directly to the tank..

Drill Pump To Drain Water Heater

Step 2 – Drain Water Heater:

Many boat yards will simply open the water heater and let it drain into your bilges. This can lead to mold, hidden trapped water and odors. I am not a fan of this corner cutting practice but do recognize it saves labor time.

To avoid this you can use a drill mounted pump like this to keep the bilge dry and to avoid draining the entire contents of the water heater into the bilge. These drill pumps are cheap and available at any Wal*Mart.

Simply connect it to the drain spigot of your water heater and then suck the water out and into a bucket in the cockpit or cabin. Once the water heater is empty disconnect the drill pump and place a few rags under the spigot to catch any remaining drips.

The Water Heater Drain Bucket

For illustrative purposes I used a bucket to catch the contents of my water heater after pumping it dry. You can also just drain it onto the floor of the cockpit or stick the hose directly into a scupper.

If you don’t mind water in your bilge by all means just drain the water heater into your boat.

The Drill Pump

This is a drill pump you can use to drain the water heater. I think it cost me about $7.00, at Wal*Mart. I personally use a 12V DC pump but these work really well for the money.

Water Heater Bypass Hose

Step 3 – Install Water Heater Bypass Hose:

IMPORTANT: Water heaters are always drained & bypassed for winterization. Please do not attempt to run antifreeze through it or you will have a very high probability of freezing and splitting it!

This is a water heater bypass hose in use. It’s installed so you don’t fill your water heater with antifreeze. You first suck all the water out then place some rags under the drain. After a few hours of rocking at the dock no more water comes out. The water heater can be left drained and the spigot open for the winter.

The bypass hose serves the function of connecting the cold water supply hose to the hot water outlet hose so the tank is entirely bypassed from the domestic water system. To install this hose simply disconnect the cold supply and hot return line for the domestic water side of the tank and then connect them together with a bypass hose.

NOTE: Do not try & bypass the engine supply & return lines for the water heaters internal heating coil. These lines will usually be black, like a radiator type hose, and will not generally be the same color as the domestic water side. When in doubt follow the lines. If they lead directly to the engine they are the wrong hoses..

Water Heater Bypass Nipple

The brass nipple between the two stainless braided hoses is acting as the bypass for this IsoTemp water heater. The bypass may not need to be hose at all.

While fitting a manual by-pass is easy, some owners are always looking to make the winterizing process even easier. For this, we offer a pre-packaged water heater by-pass kit..

Marine Water Heater By-Pass Kit (LINK)

Remove Any Water Filters

Step 4 – Remove Water Filter Cartridge:

If your boat has any on board water filters now is the time to remove them. Simply pull the cartridge out and spin the filter back together without the filter in it.

Add a Length Of Hose to Your Water Pump Supply

Step 5 – Adding a Sucking Hose:

As you can see I’ve pulled the supply hose for the water pump off the manifold. I then use a hose barb and a spare length of hose to make an extension that could reach the antifreeze bucket.

Using Turkey Baster To Prime The Pump

Step 6 – Priming The Water Pump:

Sometimes when you run a water pump dry, from draining the water tanks, it can become hard for the pump to create a new prime and begin sucking fluids again. Some pumps are worse than others in this regard.

An easy way to avoid this problem is to pre-prime the water pump using a turkey baster. Not all pumps will require this trick and if yours won’t prime this will do the trick.

Filling the Sucking Hose

I have the turkey baster full of antifreeze and am now pre-filling the hose that leads to the water pump.

Antifreeze Bucket

TIP: The 5 gallon bucket I use for antifreeze has been graduated with a Sharpie marker at each gallon. This makes it very easy for me to stop pumping, take a concentration measurement, and then continue on. In the end I know exactly how many gallons it took to get the right concentration into the system, no more, no less.

In this image the bucket has exactly 1 gallon in it…

Ready to Protect the Piping

Step 7: Sucking The Antifreeze Through The Water System:

With the hose full of antifreeze, and the domestic water pump primed, use a clean bucket, or the sucking hose stuffed into a gallon of antifreeze you are now ready to flip the switch.

Turn the water pump switch on and open each tap, in rotation, until it runs a color that looks the identical color in the bottle.

Run and test each tap until the concentration of the PG matches exactly what is in the new bottle. If you don’t have a refractomer samples in a clear glass placed next to a new undiluted sample can give somewhat decent guidance. When in doubt suck in more antifreeze.

TIP: Sucking in another gallon or two will always be less costly than a freeze up.

Make Sure You Get Pure Pink

After you flip on the water pump switch open each and every faucet, shower head or wash down fixture. I suggest doing them one at a time, first cold then hot at each faucet. Do this to ensure all the domestic plumbing are getting pure pink, the same exact color it was coming out of the bottle.

IMPORTANT: -50F & -60F RV/Marine antifreeze is already pre-diluted. It is not intended to be diluted any further. Diluted antifreeze means considerably warmer burst & freeze points.

At Two Gallons

When your sample from each tap is on the extremely diluted side the differences in color are easy to spot.. This was an approx 18F spread on the refractometer. NOT GOOD…

The often repeated method of seeing pink is not the correct manner in which to winterize your system.

They May Look The Same

In this image we have an out of the bottle sample and a spigot sample. This was measured at after 3.5 gallons had been sucked in to the system piping only. The refractometer readings were still a 4 degree spread which translates into a dangerous burst point for Maine.

The refractometer readings should match perfectly.

Don’t Forget The Sanitation System!

I know this article is about the fresh water system but I need to make a plug for the sanitation system.

This owner did a DIY winterizing and paid a really big price. The price for improperly winterizing the holding tank was massively repulsive odors in the boat. Come spring, when the frozen shit & urine melted, the leaks began and this was only one of them. The entire boat wreaked of raw sewage. it was absolutely disgusting. On top of the leak he went in late and the leak was not discovered until early June. Under the hot cover the odors had baked into everything. He had flushed one gallon of -50F PG through the head. His hoses alone held more than one gallon and the tank still had at least 3-4 gallons in it. Remember when I said -50F & -60F PG should not be diluted, this is the why.

This is also another reason I do not like elcheapo PVC sanitation hose. Every leak from the freezing was in the white PVC hose… Rubber based hoses may have survived this, PVC did not.

Sanitation System Punch List:

1- Holding tanks should be completely empty before you winterize them.

2- Hoses from head to tank should be pre-purged of effluent by dry pumping.

3- Try to wash out your holding tank before putting the boat away. Most tanks have a clean out port, use it.

4- Ask your pump out guy to do a flush service. Evacuate, fill with clean water, re-evacuate.

5- You may need a manual pump to get the tank dry. Pump into a 5 gallon bucket and pour it into a land based toilet.

As a Point Of Reference

I do not accept sanitation odors as normal on our boat, or any boat. As a point of reference this is what the inside of the holding tank looks like on our boat each fall. The photo was taken through the clean out port. This is what it looks like before she is winterized.

The tank is pumped out, back flushed, pumped out again then physically hosed out via the clean out port. I then fully bleach sanitize the tank and it is 100% drained via a dip tube and utility pump. I use 1/2″ PEX as the dip tube and a small utility pump to get all the contents out.. A little extra work? You bet, but well worth it to our family. The hoses are also pre-purged/rinsed before any antifreeze goes into the system.

We have zero sanitation odors on our vessel…. (wink)

When In Doubt…

I will leave you with this image..

I simply can not stress enough the importance of not diluting the PG mixture in your systems. When in doubt suck more in or physically test it with a refractometer..

IMPORTANT: When using a refractometer the best practice is to match a test sample from the bottle to what is coming out the taps or exhaust, if doing an engine. Ignore the numbers or specific gravity segments and just make sure the bottle sample matches the tap sample at the same line or point in the refractometer. You are simply comparing a bottle sample on the refractometer to the tap sample. They should line up identically.

Water heaters are always drained and by-passed you do not run antifreeze through a water heater. See red highlighted paragraph.

Good luck, and don’t dilute!!

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External Strainers OMG

Rod Collins — Wed, 04 Mar 2015 03:15:54 +0000

“RC My Engine is Overheating?”

Over the years I have really grown to distrust and dislike external intake strainers of either the scoop type or the non directional (sailboat style) round type. The real danger in these devices comes when you have a blockage and can’t get to the crud to clean it. They often require a dive over the side with a coat hanger but that does not always work.

Inside Strainer:

To ream out an intake from inside, some pre-planning can make this a dry and easy task. It can be done in under three minutes if set up correctly.

1- You need an intake hose that can be held up higher than the static waterline.

2- You need a snake or a BRT (blockage reaming tool). Mine consists of an oak dowel cut to the correct length.

3- If a blockage occurs before the internal strainer, close the seacock, remove the inlet hose from strainer, hold the hose high and straight above water-line, open the seacock and ream it out with BRT…

The harsh reality of external strainers is that they can become can be a safety hazard, if they have not already. I find when intakes are plumbed properly there is little to no need for any sort of external strainer. You can far more safely ream out your intake from INSIDE the vessel if you don’t have an external strainer and this can be a huge safety margin when you don’t have to physically get into the water. In just one season here in Maine I was in the water three times with a coat hanger…(cussing)

If you’re still concerned about clogs in the intake, and not noticing them, you can insert a flow detector alarm on the intake hose or just pay close attention to your exhaust note. When it starts to sound a little hollow you’ll know you have some flow issues.

Below you’ll see some of the reasons why I don’t like external strainers, some operator error, and some strainer error…..

A 1″ Perko Strainer With 1 Piece Sweeping Elbows

This is what a internal strainer looks like. Also note the 1 piece bronze sweeping elbows. Sweeping elbows are far less prone to plugging up, before the debris hits the internal strainer basket. I prefer to see a bare minimum of 1″ for an engine intake, regardless of the size engine.

Internal Strainer Tips:

1- Make your intake hose, from the seacock to the strainer, long enough so that when removed from the strainer inlet it can be held above the static waterline with one hand and reamed out with the other hand. If it plugs between the strainer and seacock remove hose from strainer inlet, hold it high and straight, and use a pre-made “blockage-reaming-stick” to push the blockage back into the ocean. If done right this takes less than two to three minutes.

2- Use a minimum of a 1″ intake seacock, intake hose and 1″ strainer, I much prefer the bronze Perko or Groco strainers to the all the plastic models.

3- Any elbows in the intake path to the strainer should be sweeping 90’s (gently curved 90’s) not hard turn 90’s.

4- Any of these bronze 90’s should be a one-piece elbow, not a male adapter and an elbow. Using sweep-ells helps get any crud passed into the strainer basket and not stuck in-between the seacock and strainer.

Wrong Elbow for a Strainer

This is simply the wrong type of elbow to use with an internal basket type strainer. They are prone to plugging at the elbow instead of allowing debris to pass through and into the strainer basket.

A Well Designed Internal Strainer System

This owner hit a nasty patch of eel grass. All the eel grass wound up in the basket, exactly as it should. It was not clogging the intake seacock, hose or elbow.

Cleaning this eel grass required no diving, no male shrinkage (“I was in the pool” George Costanza) & no danger. Simply removing the strainers clean out cap and lifting out the SS basket was all that was required.

This is a 1″ Groco ARG-1000-S bronze strainer with 1″ Groco bronze sweeping elbows feeding it. A well done installation.

The Dreaded 1 Piece External Strainer

In areas with high barnacle or muscle growth these creatures know no bounds and often take up residence in the area known as no-mans-land. This is the area hiding behind the intake screen that you simply can’t get to. After spending nearly three hours one day, in really, really cold water, even with a wet suit, trying to get eel grass out of one, I vowed to never, ever have another external strainer.

Keep In Mind: Any time you dive-in your risk goes up.

A diver spent two hours trying to get the barnacles out of this one and it still netted insufficient water flow.

This particular strainer is one-piece meaning the thru-hull fitting and strainer are one integral piece. The grate could not be removed for a proper cleaning so the boat had to be hauled at a fairly large expense. Because the owner could not see up into the area, or get bottom paint into the thru-hull he had no idea the barnacles had nearly blocked off his entire intake.

Cause = Eel Grass & Mussel Family Taking up Residence

The owner dove on this one four times in one season. His engine was still over heating and he burned up two impellers. Top solve this owner chronic clogging issues a 1″ internal bronze Perko strainer was installed and he’s not been in the water since, to remedy an intake clog.

Boat Moored in a Tidal River

This owner did not even need to run the motor for his scoop-strainer to clog up. This scoop-strainer was on a sailboat and the direction/orientation was an incorrect installation.

If installing a scoop-strainer on a sailboat it should face backwards or opposite the direction of sail. The correct strainer for a sailboat is round and non-directional. Sadly far too many owners, builders and DIY’s are not aware that non-directional external sailboat strainers exist.

Cause river current & improper strainer direction/orientation for a sailboat.

Cause = Mussels & Marine Growth

Here’s another one piece external scoop-strainer installed improperly on a sailboat with the scoop facing forward. According to the owner this scoop was spotless when he launched the vessel and he stated;

“I spent nearly two hours with a coat hanger and picks cleaning it out before she launched.”

The owner claims he even used an artists paint brush to get bottom paint “up in there“.

Result of the blockage = engine over heating

Cause – Eeel Grass

The eel grass plug on this boat was so bad the 74 year old owner lost all engine water flow. He had no way to clear the blockage from inside the boat and his wife was adamant he was not getting in the water..

Result = Boat was towed into a marina and required a haul out. Cha-Ching $$$$$…...

Cause = Barnacle Colony

The photo does not depict this very well but the entire thru-hull was plugged solid with barnacles because the owner could not get to it to paint it..

Cause = Mussel Squatters

A family of mussels decided to become squatters in this owners intake strainer..

Cause = Barnacle Colony

In this image we don’t have an external strainer and it shows what a barnacle blockage looks like behind and intake strainer. If you don’t protect the thru-hull with bottom paint the barnacles with grow. With external strainers this requires removal, if they can be, and a proper application of bottom paint.

This particular owner had suffered for years from a chronic overheating issues. He had spent thousands in boat yard expenses to “remedy” the chronic over-heating problem. No one had been able to solve it.

The problem here was not an external strainer but rather an intake fitting that was simply too small and too restrictive. The intake seacock was bumped to 1″ with a new internal 1″ strainer and the engine has not overheated once in the last 11 years. Sometimes the fix is so obvious & easy you look beyond it…

So what was the problem with this vessel?

This was a 1/2″ intake with an actual ID of less than 3/8″. The owner claimed he could not even fit a paint brush up in there. What was the boat builder thinking using a less than 3/8″ ID intake, for a marine diesel, is beyond me.

HYDROLOCK! Cause = Improper Orientation of Scoop Strainer

This owner was the lucky recipient of an engine hydrolock event while under sail. When he went to start the engine a cylinder was filled with water, and water is not-compressible. He though something was wrong with the starter motor, so kept trying, and he eventually burned it up. A dead starter motor on top of a hydrolock.. Cha-ching $$$$$….

“But RC it worked for 6 years with no issues.”

Another way to look at that statement:

“You got lucky for 6 years.”

Yes, a “professional” boatyard did this installation… Apparently no one explained to them that when sailing a scoop-strainer can potentially force water up and over the siphon break, into the water lift muffler, and can eventually back fill a cylinder and cause a hydrolock..

Please let me be very clear on this point:

Raw water pump impellers are not shut off valves!

Impellers do and can leak water past them. Facing a scoop-strainer forward is simply an incorrect installation/orientation for a sailboat. Please, if your scoop strainer faces forward consider;

1- Removing it entirely

2- Installing a non-directional sailboat strainer

3- Reversing it

If you’ve not filled your engine with sea-water, and experienced a hydrolock, consider yourself lucky.

Cause = Boatyard

This owner pays the boat yard to apply his bottom paint. I would suggest he’s paying too much!!

“RC My engine is over heating and spits steam out the stern.”

Gee, I can’t understand why….??? (bangs head on brick wall)

Cause = Lack of Maintenance

This external strainer is removable and the owner fully admitted to never removing it, cleaning and painting it. Thru-Hull totally clogged.

Another 1 Piece Strainer

1- Lack of maintenance caused by the strainer internals being inaccessible due to the 1 piece design.

2- Another improper scoop orientation on a sailboat. A hydrolock event is a major potential.

Owner Had Already Done a “Dive Cleaning”…

Engine still over heating…

Mussels..

Mussels, poor maintenance and an incorrect scoop orientation for a sailboat.

RC My Engine is Over Heating……..

You guessed it, “my boat yard does the bottom painting“…….

While this is the correct type strainer for a sailboat (non-directional), it’s totally occluded by bottom paint…..

Cause = Mussels & Marine Growth

Correct type of strainer for a sailboat, but totally plugged due to inaccessible marine growth.

A Well Designed External Strainer Can Be Opened

If you still insist on an external strainer, there is only one good method. This Groco non-directional sailboat strainer opens and can be cleaned and maintained.

TIP: Face the hinge towards the bow so that when, not if, you drop the pin or ring when diving to clean it, the strainer door will not hang open and catch weeds and will instead tend to close.

This Was Done by the Owner Himself.

Ouch……

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Seacock Failure Testing

Rod Collins — Mon, 09 Jan 2012 15:42:44 +0000

The Test Bench

I had been meaning to test the strength of a ball valve threaded directly onto a thru-hull, as many production builders do for seacock installations, but never actually got around to completing that task until now.

Many of the builders, who install seacocks in this manner, very often display the ABYC logo quite proudly suggesting their vessels are actually built to meet the minimum safety standards. In all fairness to the builders I suspect they actually believe these installations do or would meet the minimum safety standards but as I found out they certainly may not.

We can’t really blame the builders for installing UL Marine parts and then not having them meet the minimum standards, or can we? While a boat owner may assume the manufacturers would have tested these fittings for the application into which they are sold, they clearly have not.

As conducted the testing, to ABYC standards, it became apparent that a 3/4″ Marine UL bronze valve threaded to a 3/4″ Marine UL rated thru-hull fitting, does not meet ABYC H-27 Standards.

FAILURE = 404 Pounds

REQUIREMENT = 500 Pounds for 30 Seconds

This set up failed at just 404 pounds and I was an 1 3/8″ below the inboard end of the assembly so I had slightly less leverage than I would have had I been able to apply the load at the absolute inboard end of the assembly. The assembly includes all the hard piping usually ending with a male hose adapter or other bronze or Marelon fitting.

The bare minimum strength requirement, for installed seacocks under ABYC H-27, is to support a 500 pound static load for 30 seconds at the inboard end of the installed assembly.

Does this test mean a seacock like this will fail in normal use? Probably not but there is a higher probability than a seacock assembly that actually meets the ABYC standard. We had one fail on us when a spare alternator slid across a shelf and hit the in-board end of a seacock assembly, so it can/could potentially happen and has happened.. That event scared the living crap out of me and made me a firm believer in proper flanged seacocks.

When buying a boat with this type of installation please be aware of and know that it is, and can be, a potential week point that may not meet the minimum ABYC safety standards for seacocks and thru-hull fittings, at least in the 3/4″ size range.

EDIT: I later tested a 1″ thru-hull & ball valve combo and had it fail at below 500 pounds as well. It failed at 458 pounds.

The Safety Standards

ABYC H-27 Definitions:

27.4.4 Seacock – A type of valve used to control intake or discharge of water through the hull. It is operated by a lever type handle usually operating through a 90° arc, giving a clear indication of whether it is open or shut, and is typically of the two following types:

27.4.4.1 Flanged Sea Valve – A Seacock with an integral flange used to individually and securely mount the device directly to the boat hull structure.

27.4.4.2 In Line Ball Valve – A Seacock designed to be supported entirely by the through-hull fitting.

ABYC H-27 Key Points:

27.5.1 All piping, tubing, or hose lines penetrating the hull below the maximum heeled waterline, shall be equipped with a seacock to stop the admission of water in the event of failure of pipes, tubing, or hose.

27.5.4 Seacocks shall be designed and constructed to meet ANSI/UL 1121, Marine Through-Hull Fittings and Sea-Valves.

27.5.5 Thru-hull fittings shall be designed and constructed to meet ANSI/UL 1121, Marine Through-Hull Fittings and Sea-Valves.

27.6.1 A seacock shall be securely mounted so that the assembly will withstand a 500 pound (227 Kg) static force applied for 30 seconds to the inboard end of the assembly, without the assembly failing to stop the ingress of water.

27.6.1.1 The installation shall prevent any movement of the assembly.

27.6.1.3 Threads used in seacock installations shall be compatible (eg. NPT to NPT, NPS to NPS).

The Testing

Rather than trying to describe the failure with photos I made a video, that is unedited, to show the testing and failure point. The thru-hull failed at 404 pounds while trying to get to the 500 pounds and let it hold for 30 seconds. It never even made it to the ABYC bare minimum let alone hold that for 30 seconds.

The Test

The tests were performed in my shop using the work bench as the test jig. I was planning to rig up some 5/8″ thick fiberglass and bolting it to the bench using some big backing plates but after running some numbers it appeared the 3/4″ plywood should handle the loads, and it did.

To measure the load on the seacock I used a calibrated digital load cell and applied the load gradually to the seacock per ABYC/UL testing procedures. The load was measured in pounds and set to capture the moment of failure or “peak hold”. To apply the load gradually and steadily I used an old Lewmar self tailing winch attached to the end of the work bench.

The thru-hull was fitted to my bench and tightened down well using a spud wrench. The valve was then threaded onto it and the elbow threaded into the valve. I was able to get 4 full turns on the valve to thru-hull.

The ball valve to thru-hull is a known thread mismatch, NPS to NPT, but this is what is very often done by builders, boat yards and DIY’s. I wanted to mimic a “real world” type installation and most, at least in bronze, are of mixed parts, not just one brand. It was not the thread mismatch that failed.

This image shows a close up of the failure. It’s not a surprise that it failed where it did.

Materials

The materials for this test were all off the shelf UL Mairne products. I purchased everything from Hamilton Marine in Portland, ME.

To mimic what a boat owner, or boat yard may install, the components were a mix of what was on hand at the chandlery. The bronze UL Marine thru-hull fitting was made by Apollo/Conbraco, the UL Marine valve by Groco and the bronze elbow was also manufactured by Groco.

Where The Load Was Applied

If you look at the video you’ll see where the “load” was applied to the elbow which is a full 1 3/8″ inward of where the ABYC load is to be applied at the inboard end of the assembly. Here I’m measuring the load contact point from the inboard end of the assembly.

I just did not have a good way to apply the load to the actual inboard end of the assembly of this particular 90 degree hose adapter. In the process I gave up 1 3/8″ of lever. Moving down 1 3/8″ on the assembly actually favors the seacock when testing to ABYC H-27 standards. Despite this 1 3/8″ of favorable advantage, for the seacock assembly, the thru-hull still failed at 404 pounds and never got close to 500 pounds for 30 seconds.

A straight male hose adapter is even taller than the elbow and would thus provide for more lever and move the inboard end of the assembly further away from the hull.

The Inboard End

On the inboard end there was just 7/8″ of exposed thru-hull which, as I previously mentioned, mimics the installations I see on a daily basis. When I see a valve on a thru-hull I rarely if ever see them cut shorter. It would certainly help to make the assembly shorter but I just don’t see this done very often.

Even if I managed to get the valve within 1/8″ of the thru-hull nut, and then moved the load to the proper positioning for ABYC H-27, the thru-hull would have still failed at well below the standard of 500 pounds at the inboard end of the assembly for 30 seconds.

This Was a 2011 Production Sailboat

Keeping the assembly shorter and closer to the hull would definitely help and limit the lever-arm that could be applied to the thru-hull but in this case they actually added to the height. Ouch!! A flanged seacock would be significantly stronger in this application and should meet the 500 pound standard even using this myriad of hard piping.

How about this builder….. Someone paid over $200k for this boat! Is this type of installation worthy of $200,000.00 ? I’ll let you be the judge.

In an installation like this the seacock assembly should end at the male hose adapter, then have soft hose, then any additional piping. Instead this builder decided to make the inboard end of the assembly nearly 1 foot tall… What is it Forest Gump used to say…?

Cut It Shorter?

As I mentioned builders rarely, if ever, cut the thru-hulls shorter for better strength characteristics. Cutting them shorter would reduce the lever-arm but negate any thread match if a combination threaded thru-hull was used. A real Catch 22 for a builder who likes to pinch pennies….

Please click on this photo and ask yourself how one might actually get to the thru-hull nut if you needed to? Is this level of build acceptable on a $329,000.000 vessel?

The Only Reason…

The builders get away with installations like this, because we the buyers allow it.

If you want better construction techniques keeping your family afloat, it needs to start with us, the consumer. This was another 2011 brand spanking new six figure vessel.

Have Faith….

Some builders do spend the time to make their vessels safe & robust. This was also a 2011 production sailboat. She had been fitted with bronze flanged seacocks, utilized solid fiberglass backing plates and the flanges were through bolted to the solid fiberglass hull. While some builders are off pinching pennies other builders actual do care about below waterline integrity.

If I was paying six figures for a vessel, & I did in 2005, I would expect well fitted, robust below water seacocks in either Marelon or bronze. As a buyer you should demand more than the crap some of these builders are stuffing you with…

A Proper Installation in Bronze

This was a nicely executed seacock installation on a brand new Island Packet. Island Packet even used solid fiberglass backing blocks as opposed to plywood.. Builders like this should be commended for not cutting corners, not pinching pennies and giving the customer a well executed installation in regards to below water seacocks.

Your below waterline seacocks are not a joke, not optional and are not a place to cut corners. Consider what is between you and the open ocean before plunking down 150K- 400K on a penny pinched vessel. Before taking deliver of a vessel, with a piss-poor seacock installation, do your best to negotiate proper seacocks into the deal. I would suggest refusing to take delivery until proper flanged bronze or Marelon OEM / 93 Series seacocks have been installed.

Good luck & happy boating!

The post Seacock Failure Testing appeared first on Marine How To.

Servicing Tapered Cone Seacocks

Rod Collins — Sat, 15 Mar 2008 15:00:51 +0000

Anatomy of a Tapered Cone Seacock

These are the parts of a Spartan Marine tapered cone or tapered plug seacock. Over the years there were many brands of tapered cone seacocks but only two that I know of remain, Spartan in Maine and Blakes over in Europe.

At one time there were Spartan, Blakes, Groco, Wilcox Crittenden, Buck Algonquin and others that all made this type of seacock.

The Tapered Cone Seacock

In this photo we can see the cone or plug and the taper is evident. The valve body has a corresponding taper in it and the two are lap fit or ground to fit and mate nearly perfectly.

The beautiful thing about these robust bronze seacocks is they are made from the same material, all 85-5-5-5 bronze. Eighty-five-three-five bronze is made up of; 85% Copper, 5% Tin, 5% Lead (for machining ease) and only 5% Zinc. 85-5-5-5 bronze is one of the most corrosion and dezincification resistant forms of bronze used in the marine industry.

In contrast most propellers & prop struts are made of a Manganese Bronze which is anywhere between 26% & 40% Zinc. Which of these bronze materials do you think will last longer in the marine environment? There are no dissimilar materials in most tapered cone/plug seacocks unlike a gate valve or ball valve. Even a Marine UL rated ball valve has dissimilar metals in it..

In this photo we can also see the dog washer flat spots. This dog washer rides around the valve body with the cone and the dog creates positive stops on either side. There are matching dogs cast into the body of the valve.

When re-installing the cone the flat spot should be facing up. This allows you to see the actual orientation of the valve hole by looking at the dog. The flat spot is in-line with the cone/plug hole and the valve body dogs are designed for this orientation at 12:00 when open.

If you install the dog upside down at 6:00 you will bend the dog on the valve body dogs as they are only machined flat on top and have a ramp or slope on the bottom that will bend an improperly installed dog washer.

All Spartan seacocks have dog washers and valve body stop dogs. Despite what many Cape Dory owners believe are Spartan seacocks they can often be Wilcox Crittenden seacocks. Cape Dory used WC seacocks when they ran out of Spartans or could not get them in time. If you don’t have dog ear washers your valves are likely not Spartans.

The Tapered Cone Seacock 2

In this photo you can see the machined grooves in the bottom of the valve body. They are machined in to help retain a marine sealant and thus prevent leaks.

You can also see the proper placement of the Jam/Jamb nut and flange nut. I purposely placed the dog washer on backwards to show what not to do. The dog should always face the valve body and with valve open be oriented at 12:00.

UL Marine Label

It should go without saying but when doing below the waterline seacock/sea valve work the parts should be UL Marine labeled.

Groco, Spartan, Forespar/Marelon, Apollo/Conbraco, Buck Algonquin and others all sell UL Marine rated seacocks & valves. If it does not say UL Marine, or come from a legitimate manufacturer, you would be best to purchase other products that do meet the stringent UL Marine testing standards.

Brand New Spartan Seacock

This is a brand new Spartan Seacock. These are wonderful and expensive products that can last well beyond 30+ years. According to Spartan the average life they are seeing is 30 years. Keep in mind though that many of the valves, in this average, have not been routinely or well maintained.

Tapered cone seacocks if cleaned & greased yearly, and lapped when needed, can likely out last you. Sadly many don’t service them regularly and they then need replacement sooner than they should.

These seacocks were installed by many reputable builders such as Sabre, Pearson, Tartan, C&C, Cape Dory, Bristol, Hinckley, Morris, Shannon Yachts and others. Today very few builders other than Robinhood/Cape Dory and Shannon still use them though there are a few Down East Maine builders who will still use nothing but. With price competition the way it is builders have moved to less expensive, though not necessarily better, alternatives.

Wrenches

If servicing Spartan seacocks you’ll need two 15/16″ wrenches or a 15/16″ wrench and a smaller 3/4″ wrench for the smaller size jam nuts on the 3/4″ valves.

It’s important to note that you will need a thin spanner type wrench as the flange nut is thinner than most 15/16″ wrenches. The Wilcox Crittenden valves will take a full thickness 15/16″ wrench on the flange nut but the Spartans will not.

What I did is simply grind down a Harbor Freight quality 15/16″ wrench on my bench grinder to fit the Spartan flange nut. If your wrench is too thick you won’t be able to effectively lock the two nuts together and they may work loose.

If you click on this picture, to make it larger, you can see where I ground this wrench thinner to fit the jam nut. This took about 5 minutes on a bench grinder and I think I paid about $3.00 for the wrench.

Spartan Wrench

Of course if you’re lucky enough to own a vessel with Spartan seacocks then you might want to spring for their 316 stainless steel seacock wrench. I own one and it’s worth it as the length is just right.

It also has a hole in the end for a lanyard so you don’t drop it into the black hole that is your bilge!

Seacock Grease

Grease is grease right? Well, no, it’s not. Over the years, when I have been out of the Spartan Seacock grease, I have tried everything from standard white lithium grease to expensive synthetic grease like Morey’s Red or Amsoil waterproof synthetic grease. None of these wonder greases has worked nearly as well, or lasted as long, as the grease sold by Spartan Marine.

This Spartan lithium based grease is THICK because it can be. Picture cold peanut butter and you’ll have the consistency about right. Spartan has added some proprietary and top secret Tony the Tiger like ingredients that actually do work. Trailer bearing grease is thinner, because it has to be. These valves only ever turn up and down maybe 60 times per year, they are not spinning at 70MPH while driving 100 miles to a boat launch ramp. Because these valves rotate less than a full revolution the grease can be significantly thicker & considerably more viscous, for the application, and it just works.

Spartan is fairly adamant that you not use a synthetic grease and I can concur with their suggestion. Many Cape Dorian’s swear by Morey’s Red but I still find the Spartan grease to out perform it fairly handily. I find synthetics get hard, turn gummy and have less film thickness between the cone and body. As a result the valves leak sooner and become hard to turn sooner than when I use genuine Spartan seacock grease.

The grease is about $12.00 for a tub that will last many years.

Lapping Compound

Every so often the tapered cones/plugs need to be lap fit to the valve body with a lapping compound or basically liquid sandpaper. The Spartan Lap Compound is a 320 grit silicon carbide in an oil/grease base. It works very well and is specifically made by Spartan for their seacocks.

You can also buy lapping compound made by Loctite called Clover Compound. It comes in a 320 grit formula but it’s actually more expensive than the Spartan lapping compound.

My only complaint with the Spartan compound is that the oil and silicon carbide separate and it needs to be stirred well with each use. Not a real big deal..

Getting Started

1- First use the two wrenches to loosen the jam nut from the flange nut.

2- Remove jam nut, flange nut and dog washer from the cone/plug shaft and set aside. Some brands like the old Wilcox Crittenden seacocks did not have “dogs” on the washer. Many a tapered cone owner, myself included, have dropped jam nuts, flange nuts or the dog washer into the bilge during removal or re-installation. A wise man once suggested that I wrap a towel around the base of the seacock when removing the pieces. It works! The towel prevents the old bounce & slide disappearing act. On some boats if you drop a part they are gone forever…

3- Use the handle to move the valve and the cone/plug should pop out.

4- If the valve was stuck a light tap on the nut end, with a hardwood mallet, will almost always free the cone from the valve body. If you don’t have a hardwood mallet just leave the jam nut 90% on and tap on the nut. This will prevent you from damaging the threads on the tapered cones shaft. Do not beat on it.

5- Clean the valve body and cone using a good grease cutting solvent. I like odorless mineral spirits, to thoroughly clean the inside of the valve body but three are many products that will work.

Nasty Cone/Plug

Ideally you want the most contact area you can get. I aim for about 80-90% minimum contact area between the valve body and the cone/plug but on some old, poorly maintained or worn cones that may not be doable.

Here we have what looks to be less than 30% contact and the valve had been leaking. Even a thorough cleaning and greasing may have only stopped the leaking for a short while. This valve body and cone needed to be lap fit. Keep in mind the main goal here is simply no weeping when open or closed. If 60% contact area, in the right spots does it, then you’re good to go.

It should be noted that this Spartan Seacock was 32 years old when I took these photos. Show me even one 32 year old ball valve in the marine environment still working and I’d be very surprised. This is why I like Groco’s flanged adapter so much. Ball valves just do not last like a true tapered cone seacock does because they are not easily serviceable.

In-frequent servicing leads to sea-crud build up in the spot on the cone when it is in the closed position. When you then move the valve, it carries this abrasive crud into the valve body thus wearing it down or scoring it. If you grease annually, and open your valves properly, as in 100% open, not just partially open, you can minimize this wear and prolong the time between lap fitting.

Apply Lapping Compound

With the grease removed from inside the valve body and on the cone/plug you can mix the lapping compound and apply it to the cone. It does not need to be pretty as you may do this three plus times per cone in order to check your progress.

Re-Insert Cone & Lap Fit

For Lap Fitting:

Remove handle from cone/plug by removing the set screw.
Find an Allen wrench or other device that will allow you to spin the cone rotationally 360 degrees. I am using an Allen wrench here as the “L” end works great for this.
Insert cone/plug and install the dog washer BACKWARDS with the dog facing away from the valve body.
Install flange nut and tighten so you can still turn the cone/plug with the Allen wrench.
Rotate the cone fully in a 360 degree fashion roughly ten times in the same direction.
Loosen flange nut, remove cone, wipe clean and check lapping progress.
If more fitting is needed re-apply a light layer of lapping compound and rotate the opposite direction approximately ten times and check again.

IMPORTANT: The instructions from Spartan are very misleading for lap fitting. Folks often assume they want you to use the handle in a simple back and forth motion to lap fit. This is not the case and can result in ridges and uneven lapping. Spartan is aware that they need to change their instructions to be more clear and Paul had asked me to override their instructions here for anyone who might read them.

Lap fitting should always be done in a full 360 degree circular fashion and not a 180 degree back and forth manner…

10 Turns

This is the nasty cone after 10 full rotations. It still needs some work.

20 Turns

This is how it looked after 20 turns. The second set of ten rotations I do, is in the opposite direction. I find that I rarely need to go beyond 40 turns even on really poorly maintianed cones. Somewhere around 30 rotations often seems to be the magic number.

IMPORTANT: Do not try to get any of the deeper corrosion spots out of the circular area left from the valve being closed. You would need to remove a lot more bronze than is necessary to accomplish this.

You are looking to get the most contact area you can without over grinding. Just enough to keep the valve from weeping in either the open or closed position

20 Turns Inside a 3/4″ Valve

This valve was in very rough shape at 32 years old but it cleaned up well and performs perfectly going on it’s 33rd season.

This photo also represents one reason why I dislike white PVC sanitation hose when used below the waterline. That crack was in an area only really visible to the camera. Ouch!!

Just say no to PVC hose for below waterline use..

Incomplete Valve Opening

This wear and low spot was caused by repeated incomplete openings of the seacock. This wear or low spot can be avoided if you follow the cone ear and not the handle. On Spartans you can simply look at the dog on the washer as your guide. When it is at 12:00 the cone/plug hole is perfectly centered in the hole.

Valve Not Correctly Opened

As can be seen in this image the handle feels and may look like it’s open but unless you look carefully at the ear on the cone/plug you can’t tell that it is not fully open yet.

Properly Opened

As you can see the dog is at 12:00 as is the tapered cone/plug ear. The handle makes it look like it is not open but it really is. Don’t go by the handle go by the dog, if it has one, or the cone/plug ear that the handle mounts to.

Proper opening can save some wear and tear on these valves.

Final Step

This is the final step. What you see here is way too much grease. Smear it on then wipe much of it back off. It is best to coat both the inside of the valve and the cone with grease before assembly.

WARNING: The cone and valve MUST be free and clear of ALL lapping compound before re-assembly. I find that denatured alcohol and microfiber rags work best for this but terry cloth works too. Reach your finger into the inlet and outlet and wipe them too or the lapping compound will be re-deposited onto the cone. You’ll want to clean the valve body and cone three to four times with a fresh rag each cleaning. The lapping compound has a tendency to play hide and seek and you really need to seek it out. If the lapping compound is not completely removed after lapping it can destroy a seacock.

1- After cleaning, grease the valve body and the cone/plug.

2- Insert the cone and line up the flat spot on the cone with the flat spot on the large washer. If it has a dog be sure the flat spot is facing up so the dog lands at 12:00 when open.

3- Install the flange nut and then the jam nut.

4- Adjust the valve slowly while working the grease in by moving the cone around.

5- Re-Install the handle and make final adjustment.

6- Adjust the tension so the handle needs some pressure to turn it but not so loose that it falls down on its own. This will leave room for any future adjustment that may be needed. DO NOT OVER TIGHTEN.

7- If it weeps on launch take very small turns on the flange nut until it stops weeping then lock the jam nut against the flange nut.

Before

This is just a visual of what can be done with very old tapered cone seacocks. This one was nasty and leaking badly.

After

About five minutes later it looked like this. I then cleaned it, greased it and put it back into service and it works flawlessly. This seacock had not been serviced or touched in over eight years.

Wiring Warning

This was an actual situation I found under a head sink and these were live 12V DC wires. One wire had been pinched by the dog ear and the jacket opened up. Please keep any 12V DC or 120V AC wiring away from seacocks. Wire ties are your friend..

A Bonding No, No..!

These screws are for winter draining of the seacocks for boats stored in-water. They should not be used for tying bonding wires to. These are an odd size machine screw in a special bronze that are nearly impossible to get, even from Spartan.

IMPORTANT: Bonding should be tied to the flange bolts only, not the drain plugs. Just because a couple of major builders did it incorrectly does not mean you need to as well.

If you have 30 year old drain screws, that are used for bonding, I would leave well enough alone as the threads often fail when trying to get them out.

Good luck & happy boating!!

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The post Servicing Tapered Cone Seacocks appeared first on Marine How To.

Replacing Thru-Hulls and Seacocks

Rod Collins — Fri, 22 Feb 2008 15:39:55 +0000

Tip: If you would like a higher resolution or larger photo simply click on the picture and it will get bigger.

A Poor Idea

The picture on the left is what not to do if starting from scratch and installing new seacocks. If your thru-hulls and valves, on your boat, are installed & look similar to this configuration, you’re not alone. This photo was taken on a brand new 2011 production sailboat and this installation does not meet ABYC H-27 standards, despite this builder claiming to build to ABYC standards.

Unfortunately, for many owners of production boats, the factories cut many corners to save money, proper flanged seacocks being one of them. This is understandable as the cost savings over many hundreds of boats is huge to the manufacturer. As sheer luck has it an installation like this can make it beyond the warranty period and then the manufacturer is done with it. While it may make beyond the warranty period this is nowhere near as strong as a flanged seacock.

A proper seacock installation involves more than just a thru-hull/skin fitting/mushroom-head, as some refer to them, and a valve. The problem becomes more complicated when you learn why this is not necessarily the safest way to install a seacock.

The vast majority of all available thru-hull fittings have what’s referred to as a straight thread or NPS (National Pipe Straight Thread), and the vast majority of all ball valves are a tapered thread or NPT (National Pipe Tapered Thread). NPS thread and NPT thread are not intended to be used together. Many unknowing boaters sadly know nothing about NPT or NPS threads and as such often use the two together quite incorrectly.

In short, a proper seacock should have a female NPS flange that is physically bolted to the hull to which the NPS straight thread thru-hull or mushroom head is then threaded into.

Another major problem with this installation is the mismatching of metals below the waterline. That hose barb is yellow brass and not bronze. This particular builder claimed in 2011 to build their vessels to ABYC standards but the ABYC H-27 standard / UL 1121 standards specifically states that all metals shall be galvanically compatible.

UL-1121

“The components of a through-hull fitting or sea valve shall be formed of galvanically compatible materials having the strength and resistance to corrosion necessary to withstand intended and abnormal use to which they are likely to be subjected.”

Here’s the problem, 60/40 yellow brass and 85-5-5-5 marine bronze bronze are not galvanically compatible and never have been. The 60/40 brass will become the anodic metal. ABYC compliant build my a$$!

Please remember this was a 2011 vessel. The picture below, of the broken thru-hull, comes from this same builder.

A Much Better Idea

While both this photo, and the previous photo, were taken on my workbench the plywood is representative of the hull of your boat and the bronze fittings of two very typical installation methods used today. In this photo one can easily see the major differences in how both of these installations are affixed to the hull.

This photo is representative of a proper seacock installation with a through-bolted flange and the previous photo of a not-so-good installation method with no flange and mismatched threads.

Removing the Old Thru-Hulls

This is the easy part of the project but you will need a few tools first. The must have tool for this project is called a step wrench. The step wrench can be inserted into the thru-hull and then used to tighten it into a seacock or to remove it from a seacock. With the use of some heat you can also use it to break the marine sealant free from the hull. Most step wrenches have a nice flat spot for a pipe wrench or adjustable wrench for added leverage.

I purchased my step wrench from Hamilton Marine in Portland, ME.

The photo shows the step wrench inserted into the female side of the thru-hull ready to tighten or loosen.

Removal of the old thru-hull is easy:

First remove any hose clamps attached to the hose.
Next remove the hose from the valve.
Using pipe wrenches remove the valve from the thru-hull.
Using pipe wrenches or in some locations a chisel remove the locking nut from the thru-hull.
Apply heat in the form of a heat gun to the exterior of the mushroom head part of the thru-hull.
While it’s still hot use the step wrench to break the thru-hull free from the hull and remove it.
If it was put in with a product like 3M’s 5200, & does not want to break free, sliding a three foot pipe over the wrenches handle will give you the leverage needed. You can also use a pipe wrench on the threads to break it free but this will ensure total destruction of the thru-hull.
If all of the above methods fail to break it free from the hull use a 4 1/2 inch angle grinder and grind it out being very careful not to get it too hot from the grinding so you burn the hull.

A Close Up

Here’s a close up view of the step wrench, and it’s slots, inserted into a thru-hull.

The Dogs

This photo shows the dogs or ears inside the thru-hull that allow the slot on the step wrench to grab hold and break it free or tighten it.

Making Backing Plates

Unless your hull is close to an 3/4″ thick, of solid fiberglass, you’re going to need backing plates for the seacocks. Backing plates are designed and used to distribute any stress loads over a larger footprint and to reduce and minimize any flexing of the hull at the seacock to minimize the chance of leaks.

While most boat yards and DIY boaters use wood, because it’s quick and easy, there really is a more permanent method and that is fiberglass, the same material your hull is made of.

Of course if you have a beautiful old wooden boat don’t use fiberglass. Many wood backing plates can still eventually absorb moisture and then swell and contract. Over time this can lead to a possible compromise the fit of the seacocks and the water tight integrity. Most wood’s are also far softer than solid fiberglass so it can flex some with the constant opening and closing of a seacock.

Many folks swear by coating the wood with epoxy, which I’ve done over the years, but in my experience, it really does not take that much more effort to make them out of fiberglass.

I use ssolid fiberglass for backing plates exclusively so these instructions show how to do that. If you want to use wood just replace the “epoxy” or “kitty hair” step with a product like Sikaflex 291 or 3M 4200 and secure the wood to the hull with that.

Fiberglass backing plates are easy to make but yes they are admittedly a little more time consuming. The benefit is that once you have glassed these into the boat they will last a lifetime and never need replacing. Even if you replace the seacocks ten+ years down the road the backing plate can be re-used.

My motto;

“Any job worth doing, is a job worth doing right.”

Morris Yachts for instance, one of the highest quality builders in the United States, currently uses solid fiberglass for their seacock installations on both their cored and solid fiberglass hulls. I personally feel wooden backing plates are a compromise but please do remember what you paid for this opinion when making your own decisions.

TIP: To save yourself time G-10 (epoxy resin & fiberglass) or GPO-3 (polyester resin & fiberglass) pre-formed sheets can be used in place of home made fiberglass sheets.

Fiberglass Backing Plates:

To make solid fiberglass backing plates you will need the following items.

Fiberglass laminating resin & hardener + some finishing or waxed resin.
Fiberglass in both 18oz Woven Roving and a standard 6oz Fiberglass Cloth.
A 24 X 24 inch piece of relatively thick glass.
A Fiberglass roller.
Mold release wax for the glass.

To make the backing plate board wax the glass and begin laying up, wetting out, rolling & alternating the layers of roving and cloth until you have a fiberglass board approx 5/8″ thick. The whole laminating process may take you 30 minutes. The finishing resin goes on as the last coat so it does not dry tacky.

You may also be able to find scrap pieces fiberglass around your boat yard. This would save some time instead of laminating the backing plates yourself. Even two thicknesses of thinner fiberglass epoxied together is less work than actually doing the laminating. So ask around at the yard you never know what you might find.

What about Starboard?

OK I’ve had numerous questions about the use of the plastic marine lumber Starboard and it’s many knock off iterations such as SeaBoard. Starboard is not a suitable product for a backing plate.

Starboard is far to flexible to offer any sort of rigid stiffening to the hull.
It does not stick well to any adhesives, which includes bedding compounds such as 5200, 4200 or Sikaflex and the manufacturer even backs this up. Starboard backing blocks can lead to leaks below the waterline!
The concept of a backing plate is to become one with the hull, make it thicker and add stiffness so the seal between the hull and through hull is not compromised and does not flex or move. Starboard fails in all these areas..

Starboard is a great product for many uses just not one where bonding to another substrate is required or rigidity is required. Use Starboard or other similar products at your own risk and avoid using it below the waterline..

Cut Your Backing Plates

After the fiberglass board has cured you can then proceed to drill your backing plates. This is much easier said than done. You will need at least a 5.5 to 6.5 inch hole saw and a very large and powerful drill. A Milwaukee Hole-Hawg® works well.

The friction of the six inch hole saw, on the fiberglass hole, is tremendous and can and will kill a wimpy drill. I use my drill press for this but a large and powerful 1/2 inch drill from the likes of Milwaukee, Porter Cable or DeWalt is a bare minimum. Home Depot will rent you large drills and I advise this if you don’t have a drill that is up to the task.

Trust me you will kill a Black and Decker or Ryobi before you even make it half way through your first hole.

One word of advice on drilling these backing plates is clamps! By this I mean always clamp your work down before you begin drilling or you’ll have a giant spinning fiberglass saw on your hands.

Circular fiberglass backing plates are certainly the best looking but tough on the hole saws and too much for cheap drill motors. Another practical alternative is to cut a hexagon or octagon with a miter saw or table saw. This method will be faster and easier but not as neat and leads to lots of waste material.

More Tools

In any job the correct tools will save you money in the long run. When dealing with below water applications this is especially true. For your thru-hull fittings you’ll want a properly sized hole saw for each of the sizes you’re using. This photo displays a properly sized hole saw for the task and a smaller one on the arbor.

What is a Seacock ??

A seacock is simply a valve with a built in flange into which a thru-hull/skin fitting fitting is inserted. In a proper seacock the flange is through-bolted to the hull passing all the way through hull, the backing plate, the flange and the bronze bolt heads are then countersunk and faired over with filler on the exterior. A seacock can also be a thru-hull and valve used together without flanges. The caveat here is that they need to meet the minimum strength requirements and do not have a thread-mismatch.

A flanged seacock or a flanged adapter, as pictured above, is far stronger and also much safer than screwing a ball valve directly onto the thru-hull fitting. The cross section of a threaded thru-hull fitting very thin. Because of the threads cut into it, and the full-flow design, it becomes easier for it to break off. All it takes is a tool box or other large or somewhat heavy item to slam into the valve and snap the thru-hull off to sink your boat.

Why do I focus so much on proper seacocks? I had this happen to me & my family back in the 90’s. A spare alternator hit a through hull on our old Catalina and cracked it. While the water did not rush in, and the crack was small, it was a stressful ordeal that required a haul out and repair. It is the reasons I now only use flanged seacocks or flanged adapters.

The flanged adapter is a relatively new concept in seacock technology from Groco.

In the traditional sense it’s not what one thinks of when they think of a proper seacock but it certainly has some benefits over a one piece seacock. I chose to use flanged adapters for a few reasons over a seacock with an integral flange and valve.

First they allow you to replace just the valve portion, in the future, without ever having to replace the flange or worse ripping out an entire one-piece seacock. Second they accept a standard NPS or straight thread thru-hull into the bottom and a standard NPT or tapered thread ball valve threads onto the top thus eliminating the dangerous mismatching of threads.

Groco, however, is not the only game in town and products like Spartan Marine’s tapered cone bronze seacocks can last well in excess of 30 years. I have many Spartan seacocks out there pushing upwards of 35+ years old. I also have some old tapered cone valves in a box in my barn that came out of a 72 year old wood boat that was re-planked. Those valves, cleaned up and lap fitted, still work perfectly to this day.

Many folks are also happy with Marelon which are also resistant to corrosion. Choosing a seacock configuration that allows you to sleep at night is what’s most important.

In this photo you can see the flanged adapter screwed to the work bench, the thru-hull on top of the step wrench, the bronze ball valve, a bronze street elbow, teflon tape and some pipe dope.

If you click the photo & blow it up you’ll see the difference between a tapered thread (on top of the flange) and a straight thread (the thru-hull). This should give you a better understanding of why a NPT ball valve, like the one pictured, should not really be threaded directly onto a NPS thru-hull.

Hamilton Marine in Portland, ME stocks the Groco IBVF Flanged Adaptors

Dry Fit

For this particular valve I unfortunately had very little clearance and needed to turn 90 degrees. I don’t like doing this as it adds another fitting but on some boats you have little choice. In this photo I am measuring the assembled height ahead of time to ensure it will fit the boat. Please note that the 90 degree elbow is the same bronze allow as the flanged adapter and valve, 85-5-5-5 bronze.

A nice feature of the bronze Groco ball valves is the handle can be used in two different orientations for either a right or left close or open. By simply moving the handle stop set screw, to the other hole, you can position the handle to open or close on the opposite side.

Glassing In The Backing Plates

In this photo I’ve glassed the backing plate to the hull, dry fitted it and drilled it. The picture also clearly shows why this installation needed a quick 90 degree turn for the seacock. While not ideal the seacock remains accessible and there is zero, zilch & nada in this compartment to possibly interfere with it.

To tackle this part of the process you’ll need a few things.

1- The first item is an electric drill and a coarse brass wheel to fit in the drills chuck, or an aggressive grit sand paper.

2- The second is some fiberglass kitty hair, Yes, it’s really called Kitty Hair. Kitty Hair is a thick fiberglass filler mixture consisting of of long strands of chopped fiberglass mixed with a peanut butter consistency resin. The third item is a 3 inch bolt, that fits the pilot hole from the hole saw, and some Acetone.

You can also use West System, System Three, M.A.S. Epoxy or any of the other epoxy based resins and your favorite filler. Regular old polyester fiberglass cures quickly though and bonds very well to a properly prepped surface. While polyester kitty hair is not as tough as an epoxy it’s more than strong enough for installing backing plates.

Installing the backing plate:

To begin the process you’ll want to insert the brass wheel into your drill and rough/scar up both the hull’s surface and the backing plate or use a low grit sand paper. I usually use my Fein Multi-Master and carbide rasp but for this location it did not fit. Using a brass wheel, instead of sandpaper, creates nice deep scratches on both surfaces ensuring tenacious adhesion of the backing plate to the hull.

Next vacuum up any dust and wipe both surfaces with Acetone. Now your ready to mix the Kitty Hair or epoxy what ever you chose. Follow the manufacturers directions on the can for both temperature and humidity and then mix it until you have a uniform color. In most cases the Kitty Hair hardener is blue so you can easily tell that it’s mixed thoroughly.

TIP: I prefer the use of colored hardeners with polyester or vinylester resins so you can easily tell when the resin or mixture is well mixed.

To adjust the backing plate, and center it over the existing hole, insert the three inch bolt through the hole saw’s guide hole. This will make it easy to center when you are out side the boat. You’ll be able to grab the bolt and move the plate until it’s seated and centered. Once the bolt has been inserted through the backing plate, spread a judicious amount of the Kitty Hair mixture on both the hull surface and the backing plate, then place it over the hole but don’t push down or seat it just yet. At this point climb out of the boat, grab the bolt, and center and seat the backing plate into position. Now climb back into the boat and smooth the Kitty Hair with your finger, being very careful not to move the backing plate, until you have a nice smooth fillet.

Dry Fitting The Seacock

Now that your backing plate is installed and cured the first thing to do is to drill your hole for the thru-hull. This is made easier because you have already centered it over the old hole and already have a pilot hole in the center of the backing plate left over from the large hole saw you made the backing plate with. Now you simply choose a hole saw, to match your thru-hull’s diameter, and using the existing pilot hole, drill your new mushroom-head / thru-hull hole.

Once that is done you’ll need to thread the thru-hull up into the flange and measure it for length. In most cases the thru-hull will be too long and need to be cut to size. Cutting the thru-hull stem is easy.

Measuring for thru-hull length:

1- With the thru-hull bottomed out into the flange measure from the outside of the hull to the mating side of the mushroom-head. Take this measurement and add 1/4 of an inch.

2- Insert the thru-hull into a vice carefully clamping the threads that need to be cut off, not the threads your keeping.

3- Using a hack saw cut the thru-hull to its required length.

4- Clean the threads you just cut with your drill and brass brush.

TIP: I use Lenox hack-saw blades & hole saws and they outlast cheaper stuff about 5:1.

Now that you have the proper length thru-hull, re-insert it into the flange and tighten it down by hand. Climb back into the boat and adjust your seacock to align it with it’s hose for proper orientation. Once you have everything aligned, and situated where you want it, drill your flange bolts holes, one at a time. After each hole is drilled insert a bronze bolt. Inserting a bolt, after drilling each hole, guarantees proper hole alignment by the time you get to the last one. Doing this by eye, without bolts, leaves room for the seacock to twist and a potential fit failure. There is no room for error with fiberglass like there is with wooden backing plates and all bolt holes must be perpendicular to the hull as well as perfectly centered and aligned for fit.

The next step is to countersink the machine screw heads into the hulls exterior. Again having the proper tool, in this case a countersink, is imperative. Not only must you use a countersink but it needs to be the right size for the silicon bronze slot head machine screws. Using a regular drill bit for countersinking is a huge no, no. In the picture the holes have been properly countersunk and the thru-hull hole, in the hull, is over an inch thick of solid fiberglass.

Countersink The Flange Side

In this photo I still need to countersink the flange side of the bolt holes slightly. The reason you want to do this is to create an o-ring like effect of marine bedding compound surrounding the threads. If you don’t countersink most of the sealant will squeeze out when you tighten everything down leaving very little to prevent a leak.

The premise and design is that water should never even get to the top side of the backing plate but just in case it’s best to countersink slightly and make and create an o-ring effect.

Countersinking any hole, where marine bedding compound is to be used, is a good idea especially with deck hardware. This slight countersinking makes a nice water tight gasket and also prevents crazing of the gelcoat from the sharp and abrupt edges a straight drilled hole creates.

Flanged Adapter With Bronze Ball Valve Ready To Install

At this point I’ve applied some Sikaflex 291 marine sealant and am ready to install the flange. If you look very closely you’ll see that the flange has been slightly countersunk so it’s ready. First apply the sealant to the flange, in the fashion shown, then generously circle the machine screw heads with sealant and feed the bolts up through and into the boat from the outside.

Now carefully set the flange onto the bolts. Thread the nuts and washers onto the bolts, finger tight, and then climb back outside the boat. Thread the thru-hull fitting into the flange and climb back into the boat.

To tighten the nuts, with only one person, I find it much easier to use an impact driver. I use a cordless Milwaukee M12 but there are now many small impact drivers. Be very careful with the impact driver as you don’t want to over torque them. These cordless impact drivers are now very powerful and can literally snap a 5/16″ X 18 bolt if you’re not careful.

An impact driver is a great tool that will tighten the nuts without having to have a second person outside the boat with a screw driver.

Once the nuts are tight climb back out of the boat and remove the thru-hull fitting. Clean it with Acetone then lather it up with a marine sealant of your choice. Now use a step wrench, and a large adjustable wrench, and tighten the thru-hull into the flange from outside the boat.

Once everything is tight clean up the ooze from the sealant, including any that oozed out up inside the through hull and around the exterior. Be sure to clean excess sealant from the counter sunk bolt heads so you’re ready to fill and fair the exterior with a vinyl ester filler such as 3M Marine Premium Filler.

3M Marine Premium Filler is a unique vinyl ester formulation designed for marine filling and fairing applications above or below the waterline. I would avoid the use products or fillers like Bondo or Evercoat below the waterline as they can absorb moisture. Make sure you’re using either an epoxy based fairing compound or a vinyl ester fairing compound to minimize moisture intrusion.

So why do I use Sikaflex sealants or bedding compounds rather than 3M products? That’s an easy one for me to answer. In my experience I’ve found it less aggressive in it’s adhering properties than 5200, something I really like for future repairs. I’ve had vast amounts of experience, over 30+ years, with many marine sealants and have really grown to like the Sikaflex products.

If there is one thing I’ve learned, in 30+ years of boating, it’s that almost nothing on a boat is permanent, not even a keel joint. There really is little to no need for a sealant as permanent as 3M 5200. I suspect 3M 5200 was invented to ensure future boatyard revenue. (grin)

Now don’t get me wrong I’m not saying, in any way, that Sikaflex comes apart like butter, it does not, but it comes apart easier than 5200. Try Sikaflex 291 & you’ll like it’s adhesion, flexibility and long life.

Exterior View of Installed Thru-Hull

As you can see in this photo the silicon bronze bolt heads are countersunk and most of the excess Skiaflex sealant has been wiped away.

IMPORTANT: If your vessel lacks the skin-thickness for through-bolting and countersinking the heads do not through bolt! Some boats do not have thick enough hulls for this!

The next step is to fair over the bolt heads with 3M Marine Premium Filler to get a nice smooth hull with no visible bolts.

After the fairing step I also did a complete barrier coat of the area for added moisture protection using Interlux Interprotect 2000 series barrier coat. This step is not 100% necessary but I wanted to protect and prevent any water intrusion into the recessed bolt holes as I could and also protect the hull where I had sanded thin the original gel coat..

A Few Words of Caution

WARNING: If you are one of the thrifty types who think marine rated products are a bogus marketing ploy please don’t stop reading here.

This is a photo of a one year old yellow brass Home Depot ball valve installed by the previous owner. When I asked this seasoned boating veteran why he used a ball valve from Home Depot he said;

“It was only in a pinch while coming up the ICW but after it was installed I forgot to replace it with bronze.”

This Home Depot valve was in use for about 8 months, of total in-water time, and the ball, inside the valve, was completely gone, not there, corroded away.. This valve was literally weeks away from catastrophic failure of the boat sinking type.

BE SURE WHAT YOU ARE BUYING IS MARKED UL MARINE

This is What the Exterior Looked Like

This is after only eight months of use. Again please do not cheap out on your below water metals.

Gelcoat Applied

Once the seacocks have been installed you can add a nice touch by re-gelcoating the area.

It is not too difficult to get a decent color match, this one I did by eye, and it was just about spot on. Be sure to use “waxed” gelcoat, or an air inhibitor, for the final coat or it will remain tacky. Always stir waxed gelcoat before you dip your brush or roller in. This will keep the wax thoroughly mixed.

Personally, I am not a fan of paint in a bilge area, but if you are, you can use that too. I simply prefer the durability and bonding of gelcoat over paint in damp areas.

The Finished Product

This is the finished product after a few seasons use. These seacocks are for; head sink, macerator pump & head intake. I prefer to use heavy duty mandrel formed marine hose, such as Trident or Shields, for all below waterline connections. I also prefer to use AWAB non-perforated hose clamps & I always double clamp below water applications.

Remember to close your seacocks when you leave the boat. The best way to ensure your seacocks will last and work as they should, for years and years, is to simply use & exercise them.

Good luck and happy boating!

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