spongy backing plate on intake seacock

[Mike Davis]

The backing plate made of plywood on the intake seawater seacock has a spongy feeling on the outside. Underneath the surface, the wood appears to be solid. Is it necessary to replace immediately in your opinion or can I get away with this condition for another season? Thank you

[Duncan]

Given the consequences of failure, I think you're going to have a hard time finding anyone to say "No, just leave it".
I think it's like taking a reef, i.e. the time to do it is when the idea first comes to you.

[Carl Thunberg]

I completely agree with Duncan, and you won't find anyone who will go on record saying you can get by for the season. However, you can buy some time by restoring some structural integrity to the backing plate by painting on some non-thickened slow-setting epoxy and allowing it to soak into the wood. You can brush on several thin coats until it won't take any more. That will buy you some time, but it's impossible to say how much time. The real question is, why is the backing plate getting wet? Is it from condensation, or does the seacock need to be re-bedded?

[Bill Goldsmith]

I agree that no one is likely going to say "chance it" for this season. The black box of John Vigor comes to mind. I had this happen and took the opportunity to make GRP backing plates to replace the punky wooden backing plates. It's a bit of work, and requires good tools, but it is doable DIY.

Also, can you define your "season?" If this means occasional daysails within sight of land, a 24 hour travelift available if things get worse, a really strong bilge pump and access to shore power and a spare pump if the through-hull fails, and you'll be there to monitor things, then maybe chance it for the season. If your season entails being on a mooring with no shore power, offshore or near coastal voyages or extended periods away from the boat while in the water, or any combination of these, I would just fix it now.

I have some leftover GRP backing plate material and the tooling--I can make you a GRP plate if you want--just PM me for more details.

[Mike Davis]

The seawater intake thru hull fitting needs to come off. However, it is frozen on. I tried the spud wrench to no avail. Does anyone have any other ideas? Thanks,
Mike Davis

[Bill Goldsmith]

Mike, I just e-mailed you about the backing plates, and then saw this posting. Did you use something like the tool in the picture below? If it would not budge, then apply some heat and see what happens. If you want to try the tool combo shown below, just e-mail me, we're not that far apart.

[Jim Cornwell]

Mike: Where is this through-hull located? On Yankee, raw water for engine cooling and raw water for the head are separate through-hulls with 3/4" seacocks located next to one another under the sink in the head. I can't picture where yours is, though it looks like it's in a spot where water could pool around it under certain circumstances. If that's the case the FRP backing plate suggested above sounds like a great idea.

[Steve_M]

It's the underside of the backing plate, the part you can't inspect, that should worry you. I'd go with the FRP replacement.

[Mike Davis]

This is a photo of my new intake backing plate. Thanks for all the advice and thanks Bill Goldsmith for making the plates.

[Steve Laume]

That is looking really good! That is one less thing you have to worry about.

Don't forget the bonding wire, Steve.

[Sea Hunt Video]

Bill G. and Mike D.

What is the backing plate material

Also, Mike, what sealant/caulk did you use

Thanks.

[Mike Davis]

I used grp as a backing plate and 3m 4200 as a sealant. That and hours of getting off the old sealant and backing plate resulted in a good outcome. Taking off the old plate and sealant was difficult.

[Ron M.]

Nice job. A fine wire brush in a drill or grinder and a little solvent will clean up the old caulk fast once the bulk is removed with a sharp scraper. Scotchbrite rolocs work well for final cleanup. If silicon was used get it all removed and scrub with solvent to be sure.
FRP board is available from Manhattan Supply and McMasters/Carr.

[Bill Goldsmith]

Sea Hunt (Robert),

I made the plate for Mike using 3/8" GRP I got from McMaster-Carr several years ago. (What I bought: http://www.mcmaster.com/#8537K47) It's a greenish tinted vinylester layup that is very water resistant. So far I've made five backing plates for Loonsong and the one for Mike, leaving still enough material in the sheet to make my last backing plate when the time comes (Loonsong's original factory wooden engine intake seacock plate is still solid as a rock--the head and galley seacock backing plates were punky). I make two identical 3/8" plates and glue them together for a 3/4" plate.

Bill

[marka]

I did the same throughout Linda Jean about 9 years ago. I did not double the thickness and all is still well. This stuff is expensive but worth it.