Water intrusion from trim tab mounting?

R

ripple

New member
I have a 2006 22 cruiser, and while I have had no major problems with it, I have noticed some of the workmanship issues that are discussed here frequently such as the cabinet L-brackets being fastened into the balsa core (no oversize holes/epoxy filling).

I am planning on painting my boat bottom soon and storing it in the water this season. This got me thinking about the screws that attache the trim tabs to the bottom of the transom. Does anybody know how the factory attaches the tabs? It looks to me like simple sheet metal screws into the bottom of the transom. Has anyone heard of any issues with these screws being fastened directly into the core with no epoxy filler? Any other potential issues with water intrusion at the trim tab attachement points?

Thanks for any feedback...

Dougal
 
I also have the same questions about other factory work -- like the thru-hull for the cockpit washdown and the factory mounted engine.

Regards to all, Greg
 
Hi all - I posted this question a few months ago when I was going to paint my bottom and didn't get any replies so I thought I would try again. I am now finally ready to paint my bottom and I still have the same concerns regarding the trim tab installation.

Does anyone know if there have been water intrusion problems from the area where the mounting screws penetrate the transom below the water line.

Is it possible that these screws go directly into the core without the holes having been properly drilled out and filled with epoxy?

Thanks in advance for any insight.

Dougal
 
Pull the screws and see if there is water in there. If not, just coat them with sealant (I use 3M 4200 Fast Cure) and reinstall.

I pulled all the screws that are below the water line on my boat when we bought it...now I know for sure they are sealed.

Rick
 
Dougal,
I could almost guarantee that your tabs were not installed with oversize epoxy plugs unless they were installed by an owner. There would be hours of labor involved and very high cost to to it that way. Careful installation and attention to good sealing with 4200 should give many years of reliable sealing. However I agree with Rick that at some point you should pull all the screws, clean, inspect and reseal or overdrill and epoxy fill. My experience with filling large holes on a vertical surface with epoxy was a little challenging trying to keep the filler from sagging out of the hole. I think it may not have been mixed thick enough.
 
Yes, Frequent Sea, had water intrustion into the trim tab screws area. The wet wood was entirely routed out, the area reglassed and and faired. The screws were put back in with 5200, and the area bottom painted again.

This is why I keep harping on doing the installation of screws below the water line properly. As for the scuppers, there was not problem, but I did pull them, then cut back the core, epoxy filled, and filled the screw holes (after undercutting) and then re-installed using a sealant.
 
You really should drill, cut the core back a bit, fill with epoxy and then
drill and install the screws. I don't know for certain what Bob did,
but I would bet a lot that this is what he did.

There are longer explanations in the archives should you need more
info.

Mike
 
I pulled the trim tabs off this morning and indeed the screws were installed directly into the balsa wood core with 5200 sealing the threads from water intrusion.

I bored oversize holes and routed out some core material, fortunately it was all dry. I have only ever had the boat in the water for a few days at a time, however, and I feel a lot more comfortable leaving the boat in the water full time now that I have filled the screw areas with epoxy.
 
In the case of smaller screwholes (NOT below the waterline) where oversized drilling may not be desireable cosmetically I'm wondering whether squirting in some "Git-Rot" (assuming it's still on the market) might be helpful. It wouldn't penetrate as well as if the balsa were presenting its endgrain but should penetrate some, hopefully well enough to seal off the surrounding core from water. Then followed, of course, with 4200 or similar. Not nearly the fix that overdrilling, undercutting and filling with epoxy is, but might be of help?

(Getting antsy up here in Maine with the new boat 1750 miles away!)
 
Actually, there may be balsa in the way of the trim tab screws--it depends on how the boat is made. If the balsa core (1" thick) is laid in before the plywood transom, it will reach to the back of the boat--or near it. There is also the possibility of a void there--where neither the balsa or plywood reaches this back area.

I had some wet core, plus some void. I cut out the superficial outer glass, re/laminated the glass to be solid to the depth of the screws, plus 1/4", with glass and epoxy--some fairing compound of high density was also use. But we were doing some transom repairs, so which might seem like a "big job" was only a minor part of it. Just under cutting with a dremel or an allan key etc, then filling with thickened epoxy would be proper.

Get Rot is too thin, on a vertical surface--it will not give adequate sealing, or enough material to allow the screw to bite into for safe long term holding.
 
On my 07 model I recently installed a new transducer and in that location it was balsa cored. I overdrilled and put in Marine Tex then mounted in the Marine Tex with screws and 5200. I regret not using a mounting block rather than screwing directly to the transom.
 
I just got our transom put back together after trim tab re-mounting.

If you wonder in the back of your mind whether something on your transom was installed properly, stop wondering right now and just pull some screws. Our boat had tabs purchased roughly 3 years ago based on a receipt I found but I do not know who did the actual installation or when it took place. They looked really clean and I could see a bit of sealant around the edge of the tab so I figured it was good. Well, some moisture nearby tipped me off enough to just remove the tabs and check.

The sealant around the edge was applied after mounting (for looks?) and there was in fact NO SEALANT behind the tabs or in the screw holes. Needless to say some of them were pretty soggy.

I did lots of hole enlarging/drilling and routing of wet core from outside and inside (bent nail really works well!) and jacked the boat up at an angle to drain remaining water out most effectively. After 3 weeks of fans and heat lamps followed by thin epoxy filling from the inside (just for good measure) and thick Six10 from the outside, I think we have addressed the moisture and small voids I created by removing some core material along primarily the bottom rows of mounting screws. It was actually a little surprising that most of the holes were not very wet and I count us lucky for that. They are re-installed into epoxy plugs now.

I also added a stern saver transducer block to eliminate three more holes so Ari is more water tight than ever.

Lesson.......don't just trust an unknown install... take a look!

Greg
 
None of the boats have these tab screws set in properly--and that goes for almost all boats built in production lines. In some of the hulls, there is a void/or area filled mostly with solid glass right where the transom core and the bottom core meet--and thus there is little core in the area of the tab screws.

Fortunately the moisture does not spread a long distance--as it can from screws or bolt holes which are higher up--or even worse a non sealed cap. (For example many of the 80's era Grady Whites didn't have proper sealing of the top of the transom, which in many boats is where the hull to deck joint is. Consequently there is a very high percent of these boats which have rot in the entire transom.

Good on the repair, and the transom saver! Great reminder for all of us.
 
Aurelia":310b2kzf said:
If you wonder in the back of your mind whether something on your transom was installed properly, stop wondering right now and just pull some screws.
Click to expand...

I couldn't have said it better. Sounds like you did the right thing and now you know what's in there :thup No more wondering!

I was surprised to see that, for example, the Bennett trim tab instructions said something like "dip the [tapping] screws in epoxy and then screw them into the transom." I think Bennett is a great company, with a good product and stellar customer service, but that is just not cool as a way to install something below the waterline on a cored transom, in my opinion. I did contact them and say something, as I didn't think it was up to the rest of their "fantasticness."

To be fair though, they are not alone and it's just one example, which I used because I read those instructions prior to installing my trim tabs (I ignored that part and did it a different way).. In fact, I have found that most things on most production boats (including dealer prep items and aftermarket installations) are installed with a range of treatments that goes from nothing to a glob of caulk. I'm not comfortable with that level of protection on a cored part of the boat (especially beneath the waterline).

I probably sound like a broken record on this topic, but I hate fixing wet core (and I hate seeing boats get past the "viable" point when it's a case of folks paying someone else to make repairs and the labor is just too much so they get put out to pasture - this is something I've seen more on larger sailboats, not C-Dorys).
 
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