wet spongy wood in transom-ick!!

L

lbarrett

New member
While working on adding a bilge pump on my beloved '85 classic (drilling a 1/4" hole for a screw about 4" above the floor on the transom) I struck water where one doesn't want to. Apparently a previous owner had decided the original transom drains weren't good enough and installed 1/2" brass screw-in type plugs, which necessitated drilling 3 additional holes around each one. These were either not sealed properly at the time they were installed or deteriorated subsequently, but water has definitely invaded my beautiful boat. After removing the original brass tubes I found a bunch of wet spongy wood around both drain holes. Using a screwdriver I removed an index-finger length radius of pulp around each drain and it seems there's some softness left. I believe the majority of the transom is still good and dry, as last year when I bought the boat I changed the motor out and the wood around the motor mount bolt holes were dry. I also installed an auxiliary motor bracket for which I had to drill 6 holes and they were all good.

After reading what I could find on this site and a couple of others, my plan is to let things dry out as good as I can, put some epoxy in, and re-install new drain plugs. I guess I'd like to hear if anyone else has had a similar problem, to solicit some opinions about any other options there might be, and maybe get an electronic hug from someone who's been there. It's amazing how attached to this little boat I've become-my world will be a bit out of kilter until I get this resolved-LTB.
 
ibarrett-

Sorry to hear about your water intrusion problem. It's not that uncommon!

The big thing you have to do is to get the area fully dry and remove the seriously damaged wood if possible. You might use a small fan to circulate air more effectively into the affected area to speed up the drying.

There's a product called Git Rot, which is a two part thin epoxy fluid which will saturate dried wood that has been water saturated and restore much of the original strength as well as seal out further moisture exposure once its hardened. It's very important to get as much of it as possible into the damaged wood.

You can fill the remaining voids with a mixture of epoxy and either sawdust, cabosil, or microballons, or, alternately, you could use a ready-made filler like MarineTex for the strongest possible filler. I'd use the latter myself.

Depending on how much of the original strength you think that you've restored, you could also glass over the weakened area with cloth and epoxy before re-drilling your holes for the drains.

Many folks have made successful repairs of this type. I'm sure you'll be OK if you take your time and do the job throughly.

Good Luck!

Joe. :teeth :thup
 
While looking through a Jamestown Distributors catalog tonight I noticed a product by Boatlife called "Git" ROT. It supposedly according to the add "Git rot pours into the finest openings, penetrates and saturates rotten wood. Cures into a resilent adhesive which arrests dry rot by bonding wood membranes together with a mass stronger than the original wood." I've never used it and hope I never need it but it may be something to consider if your problem isn't to extensive.
 
Having dealt with decks and transoms which were wet/rot more than I like to think, I would advise the hole saw method. Cut only the outer glass. Use big enough a hole saw that you think you are beyond the wet area. Then either epoxy in a wooden plug (which you can cut with the hole saw--and then epoxy/glass the outer transom glass plug in place after getting all wet wood out. In the CD 25, where there was wet wood at the bottom and transducer screws, we just filled these areas with glass and epoxy. If there is a huge area, it is best to cut out the entire outer glass, and rebuild the transom--but in this case that does not seem to be the case.

Unfortunately the "get rot" does not really resolve the problem in a case where it is wet like this. Yes, the epoxy goes off, but it traps moisture in the wood.--and eventually there can be further break down (this is from personal experience a number of years ago, where I must have used a gallon of it on a large boat's deck. Eventually had to "bite the bullet" and remove the area, and fix it correctly.

If you catch it now--the boat should be good for another 50 years. if you have a moisture meter available, it would be a good idea to check the rest of the transom--but the MM near metal will read high.

This is the reasons I keep harping on sealing any holes you put in a cored structure--even a screw in a transom or boat's bottom!
 
Well I got a chance this afternoon to get in the boat and drill some exploratory holes in the transom and finally got some good news-the wet wood is contained to a small area around both drains-about 12" long by 4" high on the starboard side and about 6" long by 3" high on the port side. I think there was more area on the starboard side because of some past shoddy sealing of a transducer. I also (very carefully!!) drilled a couple of test holes in the floor near the leaks to check if any water had gotten into the boat bottom and they were dry! So, my plan now is to let everything dry out for a while, apply some Git Rot or equivalent to the affected area, epoxy the holes and the areas around the drains (with Marine Tex or equivalent), and re-drill and install new transom drains. I've got 75 days to get this all done before our Port Hardy trip! Again-thanks to everyone who responded!!
 
Other than Git-Rot, you might investigate CPES (Clear Penetrating Expoxy Sealer). Or, if you are confident in your mixing skills, you could just thin out common epoxy resin.
 
I would suggest against thining epoxy or even using the penetrating sealers. The best results, are after the wood has dried, that any bad wood be removed, then replaced with either wood or glass and epoxy. In irregular areas, one can cut an approximate plug of wood, then coat both the void and back of the wood with thickened epoxy with short fibers, and clamp in place. The other way is to build the entire area back up with biaxial cloth, regular cloth and epoxy--using the various thickening agents as necessary. The final fairing using microlite and fumed silica. This will be stronger and fairer than using the penetrating epoxies.

From "Epoxyworks" by West Systems, Fall 1999.

"Is thinning necessary?
There is a perception that epoxy needs to penetrate deeply into wood to be effective. Sometimes this is true, but most of the time it is not. Some common misconceptions are that deep penetration of epoxy 1) makes rotted wood as strong as new, 2) increases adhesion, and 3) makes wood more waterproof. The following is a brief discussion of these points.

1) Rotted wood impregnated with epoxy does not make the damaged wood as good as new. Deep penetration of epoxy into rotted wood will make the wood hard but it will not restore its original strength. This is not important if the rotted material is non-load bearing. A rotted door threshold does not need to be strong, just hard. However, when the wood fiber is damaged, wood loses its ability to carry loads and unless the fiber is replaced, it will not regain its full strength. A rotted deck beam or sailboat mast needs more than epoxy consolidation to return the wood to its original load carrying capacity.

2) Adhesion in all but the highest density wood is not enhanced by deep penetration of the glue into the wood. Research performed at the Forest Products Laboratory showed that adhesion to birch was increased slightly by using thinned epoxy. In lower density wood species like Sitka spruce or Douglas fir, the weak link is the cross grain strength of the wood. It does not matter if the epoxy penetrates l/4" into the wood or 0.005". The strength of the wood, the amount of surface area and the adhesive ability of the glue determine the strength of a glue joint. Most types of wood glue do not penetrate deeply, yet, if used properly, they can exceed the grain strength. Epoxy is no exception.

3) Water resistance of a piece of wood is not enhanced by deep penetration. Wrapping wood in plastic makes a pretty good waterproof seal without any penetration at all. Likewise, an epoxy coating on the surface is more water-resistant than a thinned epoxy coating that has penetrated deeply into the wood because, in most instances, the epoxy thinned with solvent is porous."

My personal experience bears this out.
 
A good reference for such work is Sailboat Hull & Deck Repair. By Don Casey. Bet your local Library has it or can get it for you. I found it very very helpful for such matters.

Careful when you apply the epoxy into a void. It likes to heat up. Made me pretty nervous when my hull was smoking. :roll: A little at a time prevents this.

Good Luck

Chris Bulovsky
 
The other way to avoid overheating epoxy is to use the appropiate hardner. There are hardners which are for cold, temporate and hot weather. If mixing a large batch, then consider using the high temp hardner. Also having the filler in the epoxy will help to control the heat. You do not want the batch to become superheated. As Chris says, using smaller batches will help. Also use a less concentrated container (like a roller pan, instead of a tin can), and cool the mixture (put the container in a cooler area or in water cooled with ice if necessary.)
 
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