Leaking Seacocks General Forum Forums

No that is a haulout .... Holes in a boat under water and never easy to deal with, even when they are their by design. If we had a water box design you could do it I think but standard design boats are a haulout. If there is a way of doing in the water I have never heard of it.

You basically would have to build a box that seals to the outside of the hull and keeps water out with arms and gloves going to the inside so that you can remove and replace without water rushing in. just one thing wrong and your desperately trying to plug a major leak that could sink the boat in minutes.

I have gone to the groco or apollo ball valves also on ones I have replace. also took some 1/4 to 3/8 inch thick pads of fiberglass built up to about 1/2 to 3/4 inch and contoured them to shape of inside of hull. Then epoxied them over old hole and re drilled and then mounted new seacock on that built up pad. Before had wood pads that a couple had started to rot. Went from strong to tank strong 🙂

I would not try to fill gap with epoxy on backing plate. It leaves a relatively thick and brittle area between plate and hull. Some sea cocks already have a flattened area that was designed to mount the seacock so not an issue in those. check on that.

build up a thick fiberglass backing plate and then use sander to rough shape it to hull curvature with 36 grit. After it is close, not necessary to be perfectly matched then hit up hull real quick with 36 grit to scuff area backing plate will be bonded to. Now wipe down back of backing plate and hull several times with acetone. It's amazing how sanding will embed any oils into abrasions left by sanding. I actually clean before and after sanding. This allows for perfect adhesion. Then take some thickened epoxy and goop it on thick and stick backing plate on. I tend to wipe up drips and edges where epoxy squeezes out at this point, trying to leave a fillet of epoxy around the edges of plate also.

this is my best case do it right method. Even if you don't get it perfect just generally doing this will still be very very strong. Face it, what your replacing is a piece of teak plywood squeezed between the fitting and the hull that maybe has some 4200 or 5200 adhesive on it.

Now to totally mess with your minds and play devils advocate. Doing the above described method makes for a very strong but "rigid" system. If it gets hit hard enough stuff will probably crack or if it shifts break the seal of what little adhesive you use when setting the sea cock into the pad and hull. The older method using a wood backing plate will compress a bit and move back into place with a good thump. We found a drip leak around ours under the sink when I was working under there. I had grabbed the drain hose near the sea cock and the whole sea cock shifted a quarter inch in my hand and water started running around it into the boat in a small steady stream. The wood pad was rotten but hadn't been deformed and looked ok to visual inspection. I carefully moved the sea cock back to its original orientation and leak went back to a very slow drip as the rotten wood expanded back to its original shape around the sea cock. 5 minutes later I was talking to the boat yard arranging at haul out the next day.

What if that had been a solid glass fitting/pad and say I hit a rock and it moved it. Or someone decided to hit the inside fitting with a sledgehammer. There is no flexibility built up like in the wood pad to accept a little shifting with the input energy, to give and take so to say. I have even thought about a thick rubber seal between sea cock and fiberglass pad. Downside of that is that it is another maintenance item that as it gets older it degrades and could be the cause of a leak in and of itself. I just ended up using really thick 4200/5200 (cant remember which) tightened down sea cock most of the way on it. Let it cure and then tighened it down a bit more to compress adhesive. This was my sort of in between solution. Even more rigid I think is better than a material that will rot.

Lot of different methods have been used over the years and most of them have worked pretty good. If I were ruler and money unlimited I would have monel hull with welded standpipes and sea cocks in a waterbox arrangement. 🙂 Dry exhaust generator with in keel cooling and dual electric motors off the transom that could be raised or lower out of or into the water, with no drive shaft through the hull. 🙂 Huge battery bank for a 12 hour battery life power and diesel electric to pick up the slack after that. 🙂

sigh I would love to see some of my ideas tried.