Thru-hulls and seacocks on a E38....

[rwthomas1]

Hello All,
I tore into my '83 E38 in preparation for spring yesterday. I didn't care for the looks of several seacocks so I pulled them all today. Here is what I found:

7 total seacocks, ball valves/thru-hulls really, not the flanged seacock. 4 of them under the starboard/aft section of the galley counter in that almost impossible to reach cabinet next to the engine. The other three were in the head, almost as difficult to get at. 5 of the thru-hulls were PLASTIC topped with Marelon ball valves. The last 2 were bronze, with bronze Apollo/Conbraco valves. All thru-hulls have a tapered seat and are completely flush with the hull.

Here is the scary parts:
The large 1 1/2" valve that is the galley sink drain was only threaded onto the bronze thru-hull nipple TWO AND A HALF TURNS! It was barely hand tight. The 1 1/2" Marelon valve behind it that is connected to two of the cockpit drains was completely frozen open. The 1 1/2" hose that connects to the drains is dry-rotted/cracked on close inspection. The 3/4" PLASTIC thru-hull with Marelon valve that feeds the raw water pump had a 1 foot tall bronze extension sticking off the top. Perfect for putting plenty of torque on that plastic thru-hulls so it will snap off.....

Seeing that backing blocks are in excellent shape and the location of all the valves in such that it would be impossible to kick them or place much stress on them I am planning on replacing with ball valves again instead of the flanged seacocks. The Apollo/Conbraco valves are in decent shape so I may reuse them. The Marelon valves are decent too, but I don't really care for plastic below the waterline. At least the thru-hulls will be all bronze this time.

I am pretty sure the "not enough threads" issue with the sink drain valve and thru-hull is a NPS thread to NPT thread conflict. I think Groco makes a bronze thru-hull with the correct threads. I would prefer to replace the Marelon valve with Groco bronze. The plan is to replace what needs it, reuse what is good and reseat it all using the backing blocks that are there.

I have looked at the local marine stores and all the thru-hulls I find are designed to be surface mounted, that is they don't have a tapered face to allow them to sit flush like the current units do. Anyone know of a source for the tapered seat thru-hulls?

Any input at all on this stuff would be great. Its my first time around with all of it. Thanks, RT

 

[Tom Metzger]

Never, but never, thread non-metalic valves onto metal thru hulls, or vice versa.

I spent a very bad hour hand pumpng water out of a Hunter 40 out in the NY harbor because of this (the electric pumps were running also). The good news is that the valve could be screwed back onto the thru hull so no problem once the water was passed back outside of the hull and the squall had passed.

Some of the crew enjoyed it even less than I did.

 

[Loren Beach]

Old topic but a Good one

http://www.ericsonyachts.org/infoexchange/showthread.php?t=2705&referrerid=28

This is a link to a related thread on this site. It has pictures and within the individual messges are links to other pictures.
This topic never seems to go away, and that's appropriate due to its importance !

You should also use the "Search" capabilites of this site -- click on that word above this window. Put in words like thru hull, seacock, bronze vs marlon, and etc.....

Some members joke about the "religious war" of bronze vs Marlon, but I would say just to have a modern ball-valve seacock attached by its flange to a good backing plate. That's the main thing. The exact material really depends on which compromises you personally can live with -- since the perfect material, "unobtainium" seems to be in extremely short supply...


Loren

 

[NateHanson]

You can get flush mount thru hulls at WM, or other good suppliers. I get them at Hamilton Marine around me. They are online and prices are about 2/3 of WM.

Personally, if it were me I'd replace everything while you're at it. The equipment isn't that expensive.

Again, if it were me, I wouldn't use Ball valves. Perhaps there's not much chance of them getting knocked, but the consequences are huge! That's my take on it anyways.

 

[Loren Beach]

Describe "knocked." Not familiar with the term.
Loren

 

[u079721]

I have thought about this a lot, and I am going to go out on a limb here and offer the contrarian view that the way the factory rigged my 1989 E-38 wasn't all that bad.

True they did use plastic Forespar in-line ball valves in place of proper seacocks with plywood backings, but the through hulls are of the proper threads such that the ball valves are fully seated, not just resting on two or three threads. And at least on my 38 all of the through hulls are inside cabinets, and there is no way for anything or anyone to fall against them. (Galley sink cabinet has: sink drain, engine intake, sea water foot pump intake. Under the head sink: head intake, head output, and sink drain.)

If I were building the boat I would have installed proper seacocks. But the existing installation, while not ideal, seems safe enough that I cancelled my project of replacing all the ball valves with seacocks. There just isn't enough access inside those cabinets to do a lot of work.

I AM fanatical about closing EVERY through hull off before leaving the boat, however.

So for anyone out there planning to continue using in-line ball valves on your 38, no I don't think you're nuts. But do be sure the through hulls are compatable with the threads on the valves, and do not mix metal and plastic. And keep the valves closed when off the boat.

As for Loren's religous war of bronze vs Marlon fiber reinforced plastic.....I am a polymer chemist by trade and even I don't trust anything plastic. But hell's bells guys, the whole BOAT is made of fiber reinforced plastic! If you don't trust it for the through hull or seacock, why trust it for the hull?

 

[rwthomas1]

Well after reading all the posts in search range and the heeding the advice of the board members and a very experienced friend I am going to use proper seacocks.

The installation will likely be difficult due to the lack of space to work. I will have to do some grinding under the sink cabinet to flatten out the hull for the new backing plates. The one advantage of the seacocks is that they are tightened from the outside with the thru-hull fitting. (using the flange bolts through the backing plate only method) This method of installing will not require swinging a wrench/channellocks in the very cramped space. If this method is okay with Groco then its good enough for me.

I am on the fence about the bronze/Marelon arguement. Forespar claims the Marelon product meet UL and ABYC standards. The Marelon doesn't need to be bonded either. They also come with nice plugs so you can plug the thru-hull while in the water and disassemble the seacock for service while in the water. I didn't trust the plastic thru-hull with ball valve but the flanged seacocks would be a much stronger design. What it comes down to is who has what in stock when I go shopping tomorrow. Loren Beach's Marelon install looks very nice. Its either Forespar or top of the line Groco stainless.

Thanks all, RT

 

[NateHanson]

You don't have to bond bronze seacocks/through-hulls either. In fact you're just exposing yourself to dangerous electrolytic corrosion if you do.

 

[Loren Beach]

Rob,
No need to grind out the hull to "flatten" it. The backing plates are bedded on thickened epoxy. I use West System with high density filler.
Lots of good info at their site -
http://www.westsystem.com/

Remember to sand off the inside surface with 40 grit first and clean off dirt and any surfacing wax -- I use acetone.

Loren

 

[clohman]

I've replaced one "stuck" Marelon ball valve because of crustaceans. Since then, I lubricate them each season with below waterline grease, open and close them all each month, and am thankful I don't have to deal with electrolysis and galvanic corrosion. I also "separated" my prop shaft electrically by inserting a plastic flexible coupling. The prospect of digging-out the old bedded through hulls and "properly" re-bedding them seems more of a risk than whatever concerns you about the Marelon fittings. My 2 cents...

 

[Chris Miller]

Don't forget...

Steve brings up a great point about turning the seacocks off when you leave...
Also, don't forget to close the sink drain in the head when you are going to be doing any serious heeling. Some day I'm going to install a 1 way valve on that drain... but lots of things on the list first!
Chris

 

[Mike Thomas]

Did this one last year.

Jamestown Distributors has a nice selection of flush thru-hulls, priced fair. (Which means it 50% less than WM.)

If your on the hard. Replace everything (seacock and thru-hull) if you need to replace valve. If your bothering to do the job, do it right. Chances are, if the valves are cheap or installed wrong then the thru-hulls are cheap, installed wrong or old. Anyway you look at it they are the only things holding you above water. Why risk it?

Just as important is the bedding compound. Make sure that what you use is rated for underwater application. Typically Polysulfide for bronze and below waterline rated silicone for plastics

Mike Thomas
no relation, unless your rich

 

[rwthomas1]

I just finished up the seacocks/thru-hulls today. It was a major PITA.

-Four of the old plastic thru-hulls that were 1/2" and 3/4" had a different diameter "head" than any bronze units I could find. Since the bronze thru-hulls were smaller they left about a 1/4" gap all the way around. I filled the depression with West System and 404 filler and then installed the new bronze thru-hulls with grease on them to make an effective mold. This worked very well. I popped them out a day later, cleaned everything, etc.

-The aft seacocks didn't fit in the existing spaces left by the old thru-hulls as the seacock base flanges are a lot larger than the collar nut on a thru-hull. The inner hull liner/TAFG had to be cut back to the diameter of the new flanges and then ground flat. This is difficult and tedious in such a small space. I ended up having to build up the interior to make it parallel with the outer hull. Did the epoxy/filler trick with wax paper under the backer blocks and then thread the thru-hull nut down and leave it overnight. Again, this worked pretty well. I did have one move and the thru-hull is slightly angled compared to the others but this is cosmetic not structural.

-Backer blocks made from a piece of teak 1/2" ply, coated in West System. Attached to the Groco seacocks with bronze screws countersunk on the underside. The whole assemblies bedded in 3M 4200 with pipe dope on the top threads of the thru-hulls. Obviously the thru-hulls were bedded in 4200 as well from the outside.

-The only issue I had was the waste line seacock in the head. There was no possible way to get a Groco or any other brand of seacock to fit in the head cabinet location. Too close to the cabinet work. I ended up just using a 90* bronze street elbow on the thru-hull and a standard 1 1/4" Groco ballvalve. The thread engagement is 7 plus turns on the thru-hull to elbow joint, plenty of strength. There is no possibilty of this plumbing being kicked or stepped on. There is barely enough room in the cabinet for it on its own. Its not ideal but it is very solid. I have a wood plug tied to it.

-All below waterline hose is marine exhaust grade with the wire in it installed with the expensive AWAB clamps. I also replaced the cockpit drain/scupper line with the same marine hose and clamps.

I am happy with the way the project turned out. It was not cheap but it is bulletproof. If I care for the hardware this should be the last time I have to mess with seacocks.

Thanks for all the help! RT

 

[NateHanson]

I've used 4200 for thru-hull installation, as do some good yards I've been to, and figured that was pretty common.

Do many of you use Polysulfide?

 

[rwthomas1]

Here are the seacocks before and after!

Here are the seacocks installed! Pictures say a 1000 words.... RT

 

[Geoff Johnson]

Hinckleys and J Boats are currently constructed with Marelon thruhulls.

 

[rwthomas1]

I have no issue with new Marelon thru-hulls and seacocks. If I could have sourced them locally and quickly then I probably would have used them. Grocos were readily available so thats what she got.

Of course, as soon as the install was completed I found a new store hidden away www.newportnautical.com local to me, that had the damned Marelons instock. Since I had been misinformed they were a consignment shop I didn't check there.... Turns out they are a great, and much cheaper than "Tiffany by the Sea" (West Marine) for most stuff.

I posted the pics just to add variety to the existing seacock installation shots. Just another way of doing this. No one commented no the teak&holly backers, I am suprised! RT

 

[Geoff Johnson]

The preferred Marelon's are the Forespar OEM version shown in Loren's photos in the project section of this site. They can be disassembled while the boat is in the water. I insisted on having one installed on my head thru hull after the prior replacement froze (as did the original). However, my yard, even though they are installed in J Boats and my yard is a J Boat dealer, had a hard time convincing Forespar to supply one. I haven't seen them sold at retail.

 

[Stugy]

Is Nylon also marelon? is there a difference? Today I had to place an order for a new fitting to replace my bronze depth sounder transducer thru-hull and they no longer have the bronze available at least not for a few weeks, they told me they now use a reinforce nylon fitting with a very good safety record and in addition it is only $22 as oppose to $185. Would 4200 be safe to use on nylon? I am just about to replace my thru-hull so any input would be greatly appreciated.
Thanks
Michelle

 

[Geoff Johnson]

I believe that Marelon is just fiber reinforced nylon or some other plastic. I used 3M 101 on my depth sounder thruhull so that it could be removed in one piece. The trick is to not tighten the nut completely until the compound has had a chance to cure so that it is not completely squeezed out of the joint. However, I had my yard replace the head thruhull with one of the expensive Forespar OEM models and they glued it to the backing plate with 5200 or 4200. That however, gets a lot of force applied to it, so you want it to be really solid.