sea cocks

windrose · Post by **windrose** » Wed Mar 02, 2005 8:51 am

What are the thoughts on nylon (Marelon) vs. bronze for inland (Chesapeake Bay) and coastal sailing?

Post by **Tim** » Wed Mar 02, 2005 10:40 am

Choose whichever you like, and which suit your needs best. Many people are under the wrong impression that Marelon is plastic and somehow chintzy; well, it is plastic...in the same sense that our boats are plastic. They are glass-reinforced nylon, while our boats are glass-reinforced polyester.

One thing I found was that some of the larger sizes (1-1/2") were huge and didn't fit well in the tight spaces of a Triton. I originally planned to use Marelon, but switched to bronze because I could make the slightly smaller sizes work better.

Be sure to use only Marelon with Marelon, bronze with bronze. This means through hull, seacock, and tailpiece should all the the same material.

JonnyBoats · Post by **JonnyBoats** » Wed Mar 02, 2005 11:36 am

One thing to keep in mind is that no matter which type of seacock you choose, they require periodic servicing. Marelon (as well as bronze) seacocks should be taken apart, inspected and lubricated periodically.

When selecting your seacocks, you can look for a label stating they are ANSI/UL 1121 approved. This standard includes material and performance requirements as well as thermal, shock, vibration and rough usage tests and operational and leakage tests. You can find both Marelon and bronze seacocks that meet the standard.

I am getting ready to replace all the seacocks (6) on a Dreadnought 32, and my current thinking is that the best I can find are by Blakes http://www.blakes-lavac-taylors.co.uk/b ... acocks.htm. You can order these from Defender http://www.defender.com/product.jsp?pat ... 675&id=137

Whatever you choose, don't forget to bed and thru-bolt the seacock.

jhenson · Post by **jhenson** » Wed Mar 02, 2005 12:17 pm

Can you take apart a marelon or bronze ball-valve seacock? I am familiar with tapered bronze seacocks and how to service them, but not ball valve seacocks. I'm just wondering how you service the newer type of seacocks. I guessing that you can grease them with you finger from above through the tail piece, but maybe they have a fitting that I can't see from the catalogs.

Joe

Peter · Post by **Peter** » Wed Mar 02, 2005 1:13 pm

I found a little squirt of olive oil (extra virgin, of course) lubricates the Marelon seacocks nicely.

Post by **Tim** » Wed Mar 02, 2005 1:25 pm

I second the olive oil lube--easy to do, and safe for the fishies (delicious, even...)

Joe, you're right that the ball valves do not easily disassemble like traditional tapered plugs. They are maintenance free, except for the occational lubrication of the ball.

JonnyBoats · Post by **JonnyBoats** » Wed Mar 02, 2005 8:01 pm

For what it is worth, Boat US http://www.boatus.com/seaworthy/swmbs.asp states:

Marelon thru-hulls, which are made of glass-reinforced plastic and are acceptable for thru-hull installations below the waterline. Marelon seacocks have been tested (most sizes) and approved by Underwriters Laboratories. While probably not as prone to mechanical freezing as their bronze counterparts, Marelon seacocks must also be taken apart, inspected, and lubricated periodically.

Figment · Post by **Figment** » Wed Mar 02, 2005 10:51 pm

I'm a card-carrying Bronzeaholic, but I dig Marelon thru-hulls and seacocks. I dig anything that reduces electrolytic problems onboard.

As for strength.... When I replaced my thruhulls before my first launch, I took one of the leftover marelon nuts over to the boatyard's anvil and swung for the fences a few times with the 3pound sledge. A bronze nut might have fared better, but it would've been a judgement call.

Dan · Post by **Dan** » Wed Mar 02, 2005 10:51 pm

http://www.forespar.com/catalog/plumbing/integrated.htm

I'm going to use these and see how they work out. Forespar advertises these as OEM only, but they sold me whatever I wanted. These can be disassembled for inspection and lubrication with the boat in the water. There are provisions to drill and install four through bolts. I opted to do this and bolt the king nut through the hull as well. This way, if the mushroom head gets sheared off the side of the boat, the valve will stay put.
We'll see.
Dan

bcooke · Post by **bcooke** » Sat Apr 09, 2005 9:26 pm

I am going to be installing seacocks next week and I have this nagging question that I haven't been able to answer from all my readings and I don't trust the local "experts" as to the best way to install seacocks.

Are the threads from the through hull "pipe" threads, that is do they taper thus ensuring a seal when tightened? If so then is the thickness of the backing plate critical so that the through hull fitting and seacock tighten up just as the parts come flush with the hull/backing plate? This sounds like an overly tight tolerance to me.

Or are the threads straight and thus need something else to seal the threads from leakage. I noticed Tim used 5200 on the mounting screws for the seacock making the seacock a permanent part of the boat (short of drilling out the bolts.) Is 5200 also applied to the through hull fitting threads?

The answer is surely obvious but I keep missing this little piece somehow.

-Britton

bcooke · Post by **bcooke** » Sat Apr 09, 2005 9:30 pm

Bedding compound on the through hull threads?...

-Britton

bcooke · Post by **bcooke** » Sat Apr 09, 2005 9:31 pm

Silicon?....

hehe, okay I know that isn't it. It appears the PO didn't though :-)

-Britton

JonnyBoats · Post by **JonnyBoats** » Sat Apr 09, 2005 10:00 pm

The threads on the thruhull fittings that go into the seacock are straight (NPS) while the ones on the other side (inboard) of the seacock are tapered.

JonnyBoats · Post by **JonnyBoats** » Sat Apr 09, 2005 10:05 pm

Here is a link which details how one boat owner replaced his seacocks in a boat with a cored hull (amoung other things) http://www.wbryant.com/StellaBoat/hauls/0307/haul.htm

Post by **Tim** » Sun Apr 10, 2005 7:14 am

Yes, the through hull fitting should have straight, non-tapered threads. A true seacock valve will also have straight threads on the bottom, to allow it to be tightened properly no matter the hull thickness. The inside of the seacock accepts tapered threads, as do most regular ball valves.

This is one reason why straight ball valves (as opposed to flanged seacocks, whether ball or other type) should not be screwed onto an existing threaded through hull fitting in lieu of the proper seacock. Straight ball valves have tapered threads, which limits how far you could tighten them onto the straight threads.

Is there any reason why, short of ultimate replacement in 30 years (or more...), one would conceivably want a seacock and through hull to be anything but essentially permanent? 5200 is my choice because of its strength and relative permanence. However strong and "permanent" it is, though, it can be dealt with and removed should the need arise. If you use quality fittings and properly install and maintain them, however, there should be no need to remove those again in your lifetime. To me, seacocks are a structural element and don't fall into the same category as most hardware.

You can also seal successfully with the less agressive versions of 5200 (4200) or polysulfide. Whatever you use, use lots of it.

Ne'er shalt thou utter thy dark word "silicone", lest the devil's ill be cast upon thee.

bcooke · Post by **bcooke** » Sun Apr 10, 2005 8:31 pm

I don't plan on removing these seacocks but I have changed plans before...

So then, one could mount the seacock on a suitable backing block (using 5200 or whatever sealant on the bolts that suited one's fancy) and then screw in the through hull until the face of the through hull seats to the outside of the hull. No other sealing is required? I just had this vision of water going up the through hull fitting and then weeping back around between the straight male threads of the through hull and the female threads of the seacock. I guess those threads are tight enough without needing any sealant. I just didn't want to learn that I needed additional sealant after "welding" in the seacock. Am I thinking too much again?

-Britton

Figment · Post by **Figment** » Sun Apr 10, 2005 8:49 pm

With bronze fittings, any small amount of seepage would eventually heal itself via copper oxide, aka "green fuzz". Still, its common to lay a small bead of sealant on the inner face of the thru-hull's flange.

Post by **Tim** » Mon Apr 11, 2005 6:45 am

Well, of course you goop the heck out of the through hull flange and lower threads too (the area where they penetrate the hull). Most mushroom fittings even have a slightly dished-out underside (the side against the hull) to accommodate a plentiful bead of sealant and ensure that it is not all squeezed out when tightened.

Bill A · Post by **Bill A** » Fri Apr 15, 2005 3:04 pm

I plan on replacing my through-hulls and seacocks next week on my New 77 Catalina 27. I was reading This Old Boat, and in the Seacock installation section, one of Don Casey's steps doesn't make sense to me. Pehaps someone on this board could tell me the reason for it.

Don writes that after tightening the seacock on the through-hull, so that the bolt holes line up, then tighten the attach bolts. "Tightening the flange bolts tends to push the through-hull out of the hull as the wooden backer conforms and compresses." His next instruction is to use the wedge tool to check the through-hull for tightness. Does this mean to tighten the t-h to close up the gap that was previousely formed when the flange bolts were tightened.

Thanks
-Bill

bcooke · Post by **bcooke** » Mon Apr 18, 2005 7:28 pm

Who knows what lurks in the dark mind of Mssr. Casey... Not anyone here I guess. I have never heard that instruction before but I guess I could see it happening. How would one tighten the thru-hull after the backing nut has been tightened down though?... I wonder if backing nuts were common practice when Don wrote that. I have found some of his info to be a bit dated and the old thru-hulls on my boat were all just gooped in without backing nuts (or backing pads, or real seacocks or...)

Last trivial question and I will shut up... for a little while.

Think hard here... flush or mushroom head on the thru-hull. Does it make a lick of difference? Inquiring minds want to know.

-Britton

Post by **dasein668** » Mon Apr 18, 2005 9:48 pm

bcooke wrote:Think hard here... flush or mushroom head on the thru-hull. Does it make a lick of difference? Inquiring minds want to know.

How fair is your bottom? How burnished is your bottom paint? How many other things are sticking out through your hull?

Yes, it makes a difference. Does it make enough of a difference that your average Triton will see any noticable degredation in performance? Absolutely not.

Mushrooms are much easier to install, though.

Post by **Tim** » Tue Apr 19, 2005 6:44 am

Go mushroom. You're cruising.

bcooke · Post by **bcooke** » Tue Apr 19, 2005 8:29 am

How would one tighten the thru-hull after the backing nut has been tightened down though?...

Duh... there are no backing nuts used when the seacock is screwed on... Less grinding/more sleep.

Mushroom it is (which is good because I already bought them.) I don't want to go fast. I just want to go faster than you!

-Britton

Post by **dasein668** » Tue Apr 19, 2005 9:40 am

bcooke wrote:Mushroom it is (which is good because I already bought them.) I don't want to go fast. I just want to go faster than you!

Faster than Tim? Oh, that's easy. Faster than me? Weeeelllllll. We'll just see about that! hehe

Post by **Tim** » Tue Apr 19, 2005 11:11 am

dasein668 wrote:Faster than Tim? Oh, that's easy.

Easy, killer!

Post by **dasein668** » Tue Apr 19, 2005 11:21 am

Tim wrote:
dasein668 wrote:Faster than Tim? Oh, that's easy.
Easy, killer!

Just getting you fired up for summer, is all!

bcooke · Post by **bcooke** » Fri Apr 29, 2005 8:17 pm

Here is a trivial question to beat them all.

When installing those cupped and screened thru-hulls as used on engine raw water intakes. Do you place the screen forward or aft?

A survey of the boat yard shows a pretty even mix of installations. My boat originally had the screen facing forward but after a lengthy discussion I am on the verge of deciding that an aft facing screen would be better.

Somehow I had it in my head that the boat's forward movement and the forward facing screen would help scoop water up into the engine cooling system. I thought this was a good thing. Now I have come to believe that an Atomic 4 doesn't need help drawing the 3-4 gallons a minute that cools it and the forward facing screen is actually more likely to plug than an aft facing one.

Is there a definitive answer here?

-Britton

Post by **dasein668** » Fri Apr 29, 2005 9:37 pm

Mine faces forward. How much more definitive do you need?

hehe

Post by **Tim** » Sat Apr 30, 2005 6:55 am

I don't have one at all. They are kind of unnecessary if you have a good internal raw water strainer. It's amazing how many external strainers are clogged with bottom paint and marine growth.

However, you are right in that the so-called "scoop" strainers on sailboats tend to be evenly split between forward-and aft-facing. I actually believe the correct way, on a slow-speed boat with small engine, is to face the screen aft. High-speed boats that draw lots of cooling water do need the screens facing forward to force additional water into the intake.

bcooke · Post by **bcooke** » Sun May 01, 2005 8:34 am

We had a tie. Then I checked out Figment. It faces forward.

-Britton

Figment · Post by **Figment** » Sun May 01, 2005 5:30 pm

My powerboat roots showing through.

Actually, I'm pretty sure that the screen was facing forward when I bought the boat, and I just put it back on the same way without thinking twice.

bcooke · Post by **bcooke** » Fri May 13, 2005 7:35 pm

Just to add to the trivial data here:

The nifty Groco thru-hull installation tool doesn't work with Forespar's Marelon thru-hull. One could resort to a pair of pliers opened up to pin against the "ears" (ridges?) in the tube. Marelon isn't as tough as bronze and the "ears" will get damaged a bit though.

Thru-hull tubes are rediculously long for attaching to a seacock. According to a Marelon techie, it is okay to cut down the tube to a suitable length as long as 5-6 threads are left to engage in the seacock.

Definitely, tighten the attaching bolts, then tighten the thru-hull then tighten the bolts then tighten the thru-hull... Keep going until everything seats up nice. Took two rounds for me.

My screen faces aft.

-Britton

bcooke · Post by **bcooke** » Fri May 13, 2005 7:39 pm

One more detail.

Can you take apart a marelon or bronze ball-valve seacock?

. The Marelon unit looks like a single unit but the lower end actually screws off if you get curious enough. It allows access to the seal that fits against the ball. There is also an O-ring to seal the housing parts. I imagine the top will separate too if you wanted to try.

-Britton

bcooke · Post by **bcooke** » Sat Sep 24, 2005 11:22 am

Well, I meant to install the external strainer aft but in the rush I listened to the wise sage's advice

I don't have one at all. They are kind of unnecessary if you have a good internal raw water strainer. It's amazing how many external strainers are clogged with bottom paint and marine growth.

For me this was bad advice. The only maintenance issue I had all summer was the raw water strainer getting clogged often. When this happened the inlet hoses collapsed and the raw water pump belt started squeaking. After a while I learned the tell tale signs of squeaking pump belts and slowly rising temperatures.

I also learned to clean out my strainer every couple of hours of engine use. At one point the 90 degree fitting from the raw water seacock got jammed up. Even with the hoses removed and the seacock opened, only a dribble of water came in. I had to dive over the side to fix that problem. Next time I launch I will definitely have an external strainer. Maybe others have a better internal strainer (though I think I have a more than adequate one) or their pumps can ingest more foreign material without issues.

-Britton

Post by **Tim** » Mon Sep 26, 2005 6:40 am

That's strange...I've never had a problem at all. In fact, this season I never even had to clean my internal strainer. I check it daily when cruising. The diesels suck far more water through than an Atomic Four, so it seems doubly strange that you'd have so much trouble with external fouling.

bcooke wrote:At one point the 90 degree fitting from the raw water seacock got jammed up.

You should have a straight fitting here, and no sharp bends anywhere if you can avoid it.

bcooke wrote:When this happened the inlet hoses collapsed...

This is an application where you definitely need the stiffness of wire-reinforced hose to avoid potential collapse.

I stand by my earlier recommendation, but am sorry that it didn't turn out that way for you.

bcooke · Post by **bcooke** » Mon Sep 26, 2005 7:07 pm

I agree it is very strange. The strainer was honestly chock full several times after only a couple of hours of use.

As for straight tailpieces out of the seacocks, you are definitely right there. I have learned my lesson and it will be a better system when I re-launch. Wire reinforced hose would help too. So much to learn...

-Britton

Figment · Post by **Figment** » Mon Sep 26, 2005 7:20 pm

Doing a little bit of swamp-romping during your cruise? That's some pretty remarkable stuff.

I have what I believe to be the smallest strainer available on the market today. It holds about 6 or 8 ounces of water. At the end of the season I clean it out, but only as part of a routine. It doesn't really need to be cleaned out.

How fine is the mesh on your strainer? Mine is coarse enough to pass fine silt through, but not actual sand. If your mesh is more fine than that, I could kinda see how a little bit of slime could cause a big problem.

Water pump belt squeaking on an atomic-4? I infer that you have the raw water heat exchanger and all of that bric-a-brac. How the heck is there room in a Triton engine compartment for all of that? I'm still trying to find a decent spot for the Fireboy bottle!

I have a 90-degree tailpiece on my seacock and haven't had a problem there either. I went with the bent tailpiece because I was thinking that this would allow an easier time fitting the hose to the raw water pump, which is only about 7" away. Then I got the bright idea of using a 5' hose so I could suck antifreeze from a bucket in the cockpit during fall decomissioning, so the bent tailpiece is actually kinda in the way now. Boats are fun.

A30_John · Post by **A30_John** » Mon Sep 26, 2005 8:46 pm

That's strange...I've never had a problem at all. In fact, this season I never even had to clean my internal strainer.

Same here. And, I've motored through some serious weed piles this year. I wonder if this problem (or the lack of it) has anything to do with the location of the seawater intake on the hull. On more than one occasion I've looked back after zig zagging through a wall of seaweed, shook my head as the crud passed behind the boat, and wondered if the "hydrodynamics" of the water rushing past the hull has been what kept those weeds from being sucked into the seawater intake and clogging the strainer. Could it be that the water passing by the hull is drawing the weeds away from the hull in that area?

bcooke · Post by **bcooke** » Tue Sep 27, 2005 9:03 am

Well here is a picture I had close at hand showing my installation.

The boat came to me with freshwater cooling using the original pump (on the output side of the engine) for the freshwater and a Sherwood pump shown in the picture for pumping the raw water. The Sherwood doesn't line up well with the drive pulley (something I need to rectify someday) so that may be adding to the squeaking problem. As you can see, what used to be the battery box is now the engine service point. The raw water strainer is there on the left. The screening is pretty course and what is plugging up the strainer is rockweed and seagrass (and the occasional sea creature).

As I sit here though I am thinking that perhaps the unreinforced hose is my biggest problem. Maybe with only a little back pressure, caused by the strainer filling up- though not completely blocking, the hose is collapsing causing the real problem.

Perhaps too the inlet location is more critical than I thought. I moved my inlet forward and it is about where the Triton sink drain tube used to be. If anything it is slightly lower on the waterline but maybe not tucked up so much in the curvature in the hull.

The strainer does really fill up though. Packed full with rockweed and grass.

Maybe my pump just really sucks. Get it? Sucks. Hehe

-Britton

Figment · Post by **Figment** » Tue Sep 27, 2005 11:38 am

O

My

God

That photo gives me new appreciation for the hordes of folks ditching their A4s in favor of diesel replacements.
Note the date and time. I'm officially going to stop bitching about what a pain in the a$$ it is to work on my atomic 4. Mine is a picture of ease and simplicity by comparison.

So Britton, I think it's time that you and I put our heads together and developed some details for constructing an icebox that can slide forward out of the way (kinda like the "galley module" does, but easier) for engine work. Can you imagine what it must be like for A4-Triton owners who still have that icebox in place??????

bcooke · Post by **bcooke** » Tue Sep 27, 2005 4:48 pm

Can you imagine what it must be like for A4-Triton owners who still have that icebox in place??????

It was while I was contemplating engine work that I happened to have a big hammer in my hand. It was the coincidence of these two things that led to the removal of the icebox and galley area. The whole operation took about ten seconds to conceive and commence with the execution.

By trade I am an aircraft mechanic so working in tight spaces is something I am familiar with. It is also something I try desperately to avoid if I am not getting paid for it. Believe it or not what you see is a big improvement IMHO. The 2x4's on either side of the engine are part of my temporary galley so they will be coming back out and repositioned (and lightened, they are a bit of an overkill unless one plans on dancing on the galley). With the 2x4 supports out of the way it might not be so cramped in there.

The icebox was on my mind quite a bit this summer. One idea was simply to go without an icebox. After several days of enjoying Tim's and Nathan's hospitality and more importantly their ice for the rum and tonics, and multitude of fine cheeses for the crackers of course, I think going without would be a poor decision.

Another idea was to make the icebox shorter than what Time and Nathan came up with so that it was several inches away from the engine so I would at least have access with my hands if not my eyes to the carburetor and oil pressure switch. The fuel pump was electrified and moved forward on the bulkhead just visible in the photo to make maintenance easier. I am not sure how that would work as the edge nearest the engine is also the deepest so a lot of storage space would be lost. While smaller it would have the benefit of putting more distance between the hottest and coldest thing in the boat.

A third option would be to locate the icebox somewhere else, the hanging locker or V-berth for example. Dan Spurr shortened his settee as you know but I like full sized settees myself.

Now, a removable icebox is something I hadn't thought of... I am not sure it could be made big enough to be useful but I need to think about this. I like to tinker with the engine and I think it likes me the better for it so it would have to be pretty easy to remove. Then again with reasonable preventative maintenance the carburetor and everything else on that side should be a set and forget kinda thing.

It is a dilemma.

Of course one could always choose to only cruise in the company of fine gentlemen with diesels and iceboxes installed too. It worked once.

O

My

God

That photo gives me new appreciation for the hordes of folks ditching their A4s in favor of diesel replacements.
Note the date and time. I'm officially going to stop bitching about what a pain in the a$$ it is to work on my atomic 4. Mine is a picture of ease and simplicity by comparison.

Oh, it isn't so bad really.

And as for ditching the A4, Never!, 6.3 kts (after several speed trials) and purrs like a kitten. Okay, purrs like a BIG kitten but the boat churns up water like nobody's business. Standing over that engine while making hull speed makes me feel like a supreme example of my gender.

-Britton

Post by **Tim** » Tue Sep 27, 2005 5:21 pm

bcooke wrote:Standing over that engine while making hull speed makes me feel like a supreme example of my gender.

At least there's something! hehe

Next you'll be wearing gold chains and straight-piping your exhaust out the transom. I can see it now.

bcooke · Post by **bcooke** » Tue Sep 27, 2005 7:28 pm

Next you'll be wearing gold chains and straight-piping your exhaust out the transom. I can see it now.

God, why didn't I think of that!

grampianman · Post by **grampianman** » Wed Sep 28, 2005 8:31 am

Presenting on the PCRB Forum, for the first time ever!

Pimp my Triton!

Cheers,
Ian

Post by **dasein668** » Wed Sep 28, 2005 9:05 am

bcooke wrote:Another idea was to make the icebox shorter than what Time and Nathan came up with so that it was several inches away from the engine so I would at least have access with my hands if not my eyes to the carburetor and oil pressure switch.

Is your A4 bigger than the diesel? I narrowed my icebox about an inch or so from the original box and found that I have pretty good clearance on that side of the engine now?whereas before it was really shoe-horned in there... I have enough space there now to fit my raw water strainer and fuel filter...

Figment · Post by **Figment** » Wed Sep 28, 2005 11:05 am

The thing is that the A4 is all about side-access. Nothing that's adjustable about the A4 is accesible from the front or top. Were it not for that missing panel on the port side, I don't see how Britton would even get a hand in there to adjust carburator jets or oil pressure.

I don't have the current issue of Boatworks at hand with that table of data on small diesels, but IIRC only the Yanmar and Beta had the same or less width than the A4.

Post by **dasein668** » Wed Sep 28, 2005 11:30 am

Ah. And there's probably more adjustment required too.

Pretty much the only thing that really needs to be accessed from the side on my Yanmar is the oil dipstick. Or at least, regularly accessed. Manual fuel lift pump is over there too...

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