Glas Ply transom repair

Arne K · 05-01-2009, 05:22 PM

I'm getting ready to re-power with a 5.7 Mercruiser engine/outdrive setup so I tore out the old setup a couple of weeks ago and decided I'd clean up the transom while I'm at it. There were holes left over from a kicker bracket, nails left in from old lettering, plus the various other items commonly fastened to the transom of a boat. So I ground the nails down below the surface of the glass, drilled out the soft wood in the old screw holes, and feathered the gel coat around the old bolt holes. This is all in preparation to fill and fair with epoxy putty. There was one crack in the gel coat I found when I removed the bottom paint. So, concerned that that there may have been some water penetrating there, I went ahead and ground through the glass to the wood. It was nice, bright, dry plywood. Good news! So I went on with touching up minor cosmetics. Then I looked at the drain fitting, saw that it had screws holding on, and figured I should go ahead and remove that and re-seal it. That's when things took a turn for the worse. When I removed it, I found damp, rotten wood. I decided to investigate and cut the glass away. All the wood within 1" of the drain tube was rotted and the wood was wet for 6" all around it. I'm sure the drain had been leaking for years but always had a chance to dry out so the rot wasn't as bad as it could have been. When I pulled the motor I washed out the bilge thoroughly and the wood soaked up water then. I did some research and decided to try products from Rotdoctor. They make a penetrating epoxy solution designed to saturate and harden rotted wood as well as moisture proof good wood. I bought their penetrating solution (CPES), filler putty, and laminating resin. The plan is to dry out the transom wood, chip out the soft stuff, treat all the exposed wood with CPES, fill the chipped out area and bolt holes with epoxy filler putty, laminate a fiberglass patch, and then fair out all the areas I ground with epoxy putty. As of today, what I have accomplished is drying out the wood (soaked it with acetone, warm shop, halogen light, and fan), chipped out the wood, and applied the CPES. The CPES will need a couple of days to cure so the next step will start on Sunday. I haven't done anything like this before but I've read about it quite a bit so I think it'll work out ok. I'm going to post pictures with updates and welcome any advice offered.

This is after I discovered wet wood and did some prospecting.

After drying and grinding.

All the patching to be done.

After applying CPES.

Arne K · 05-02-2009, 09:05 PM

Did some of the patching today. I ran out of putty but got the most important part done: the bare wood on the transom where I have to laminate fiberglass. I'll need to sand the patched areas and probably do a little touch up also. Sorry about the angle of the pics. I only have a few feet between the transom and the back wall of my shop.

cutbait · 05-03-2009, 01:38 PM

to check for wet or rotten areas in a glass boat the tool used by surveyors is a hammer(small).Use it to tap around.dry areas will give a sharp report while wet or rotten will be dull.for repairs remove wood from inside and relaminate to hull.
the area around drain plug when you go to reglass you should grind off the gel-coat so you are glassing directly to the glass with out any gel-coat under the lamination.No strength to gel-coat.

Waterfish · 05-04-2009, 07:18 AM

Have you seen the book "Runabout Renovation" by Jim Anderson? The book has a whole chapter devoted to transom restoration. Some very good advice there. The book was written in 1992, back when most people were still using polyester resin for boat repair; so anywhere the book recommendes polyester resin, ignore that and use epoxy resin instead. I like the West System epoxy resin with their metered pumps.

If you Google "Runabout Renovation" you'll find many sources (including Amazon) that sell it used and new ($5.00 to $11.00). Even though you have already started the repairs of your transom, if you are not finished yet, it would be worth it to get this book.

shorthair · 05-04-2009, 11:00 AM

There's an epoxy repair product called CPES that is supposed to be real good. Also saw a product that after you got the wood out you poured this in & they claimed it was strong enough to hang an outboard on, just can't find the old bookmark sorry.

Silver Eagle · 05-07-2009, 07:56 AM

I have a 19 foot Seaswirl setting in the shop with the whole back plywood out of it, will have to re-cut new plywood and glass it in, its a big Job for sure, but new boats cost a lot and don't think they are built quite a strong, this was cause by the top of the plywood not being sealed at top, Need to get on it, I see you have addressed yours properly I wish I was that far along......Ray

tomictime · 05-07-2009, 07:01 PM

check your stringers and floors..while U are in there

Arne K · 05-07-2009, 07:55 PM

I checked everything. The only other trouble spot was where the engine cover hinges screwed down. The screw holes were stripped and I was worried about the possibility that water got in and migrated. I cut out a 4"x6" piece of plywood around these holes. Everything is dry and solid. I epoxied and glassed new plywood patches in place.

tomictime · 05-08-2009, 07:30 PM

and the limber holes?

Quote:

Originally Posted by Arne K

I checked everything. The only other trouble spot was where the engine cover hinges screwed down. The screw holes were stripped and I was worried about the possibility that water got in and migrated. I cut out a 4"x6" piece of plywood around these holes. Everything is dry and solid. I epoxied and glassed new plywood patches in place.

Arne K · 05-10-2009, 05:31 PM

This was before I applied fiberglass.

These are after fiberglassing and fairing with epoxy putty. I still have to sand and do just a little more touch-up.

Sorry I didn't get any pics of fiberglass in progress. I stayed up on work nights doing it and just wanted to hit the shower and go to bed afterward instead of getting the camera and going back outside.
I still have to drill the hole for, and install, the new drain. Then it'll be time to start prep for new paint, interior, and power plant.