Repair of Wet Wood In Transom

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Repair of Wet Wood In Transom

Postby quickenberger » Mon Feb 20, 2017 10:44 am

The air temperature here is starting to warm up enough to melt the ice away, and I started looking at the transom [of a Boston Whaler SENTRY 19 boat]. I found the through hull fittings were leaking. Also, the engine mount bolts weren't sealed very well, and water got into the wood there. The U-bolts (for the tie-down straps) also have had water intrusion. Basically, all the wood in the transom is all wet wherever I drill an inspection hole.
Luckily the wood is not rotten. It is wet, but no rot.

I am leaning towards removing all of the wood through the top transom cap with a chainsaw and filling with SEACAST. That way I do not have to worry about the wood not being completely dry and rotting five years from now. I could drill lots of little holes and use a vacuum pump and boil the water out, but I am not convinced that will completely dry out all of the wood. I could cut the outer skin away, grind out the wood, relaminate new transom core material and laminate a new skin on it, but it seems the SEACAST method may be less work.

What are your thoughts on [repair of wet wood in a Boston Whaler boat transom]? Thank you.

jimh
Posts: 11672
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Repair of Wet Wood In Transom

Postby jimh » Tue Feb 21, 2017 1:10 pm

Was the boat used in saltwater? Or freshwater?

Is the water in the transom from seawater or rain?

User avatar
Don McIntyre - MI
Posts: 126
Joined: Fri Oct 09, 2015 4:33 pm

Re: Repair of Wet Wood In Transom

Postby Don McIntyre - MI » Tue Feb 21, 2017 1:45 pm

Wet wood will eventually rot.

We had the transom replaced on our [1973], 21 Outrage, by ripping open the stern, replacing the rotted wood with actually a thicker-than-factory plywood laminate, re-glassing the stern and repainting. Your job would actually be a bit easier, as the 21-footer stern is notched in about one foot, while yours is straight, or slightly curved.

I've heard about the chainsaw method, but never talked to anyone who did it. Might need a long chainsaw? And what would the Seacast cost?

Regards - Don
Port Huron, MI

quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Re: Repair of Wet Wood In Transom

Postby quickenberger » Tue Feb 21, 2017 4:23 pm

jimh wrote:Was the boat used in saltwater? Or freshwater?

Is the water in the transom from seawater or rain?


The boat was used in salt water but then sat out in the rain for over a year. I haven't tasted the wood yet to see if it was salty. :)

quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Re: Repair of Wet Wood In Transom

Postby quickenberger » Tue Feb 21, 2017 4:30 pm

Don McIntyre - MI wrote:Wet wood will eventually rot.

We had the transom replaced on our [1973], 21 Outrage, by ripping open the stern, replacing the rotted wood with actually a thicker-than-factory plywood laminate, re-glassing the stern and repainting. Your job would actually be a bit easier, as the 21-footer stern is notched in about one foot, while yours is straight, or slightly curved.

I've heard about the chainsaw method, but never talked to anyone who did it. Might need a long chainsaw? And what would the Seacast cost?

Regards - Don
Port Huron, MI


That is my thought too. Some that I have talked to say to just run it and enjoy the boat, but I know wet wood will eventually rot. Watching how Metan Marine on youtube replaces the wood on the transom of whalers by cutting out the outer skin, removing rotten wood, re-laminating a new core and vacuum infusing glass and resin looks very doable. I do not have a chainsaw capable of at least a 25" bar so maybe cutting out the outer skin and following Metan's approach may be most feasible. Either way I want to do it right and not wait till the wood becomes truly rotten.

jimh
Posts: 11672
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Repair of Wet Wood In Transom

Postby jimh » Wed Feb 22, 2017 9:58 am

I have heard that wood only rots with freshwater. Saltwater is supposed to suppress wood rot.

quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Re: Repair of Wet Wood In Transom

Postby quickenberger » Wed Feb 22, 2017 1:49 pm

jimh wrote:I have heard that wood only rots with freshwater. Saltwater is supposed to suppress wood rot.


That is what I have heard as well. I hate to find out that it is not salt water in there and in a few years the transom gets rotten.

underbone
Posts: 12
Joined: Mon Feb 13, 2017 9:48 pm
Contact:

Re: Repair of Wet Wood In Transom

Postby underbone » Wed Feb 22, 2017 9:05 pm

I remember this site about rot repair and thought to share their article. Wonder if they have something that can keep the wood from rotting.

http://www.rotdoctor.com/glass/GLrotrepair.html

mrfipp
Posts: 5
Joined: Tue Feb 21, 2017 6:18 pm

Re: Repair of Wet Wood In Transom

Postby mrfipp » Thu Feb 23, 2017 6:31 am

jimh wrote:I have heard that wood only rots with freshwater. Saltwater is supposed to suppress wood rot.


This is true. Wooden sailing vessels scrub their decks with saltwater, never freshwater for this reason.

User avatar
andygere
Posts: 37
Joined: Sat Oct 17, 2015 2:13 pm

Re: Repair of Wet Wood In Transom

Postby andygere » Tue Feb 28, 2017 4:36 pm

When you drill inspection holes, is the wood wet all the way through, or just at the wood/glass interface?
1989 Outrage 22 Cuddy

quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Re: Repair of Wet Wood In Transom

Postby quickenberger » Sat Mar 04, 2017 8:01 am

andygere wrote:When you drill inspection holes, is the wood wet all the way through, or just at the wood/glass interface?


Its wet all the way through. I used a Harbor Freight 25" long 3/8" drill and drilled from the top cap down to about an inch of the bottom of the transom and the shavings were wet. When clearing out shavings sometimes there was foamy wet wood. I pulled vacuum on it and got a lot of water out of that one hole, but may end up needing to cut off the outer skin and grinding out the wet wood. I would like to eliminate any wood on the transom and either vacuum bag a new core in place of the wood, or replace the skin and pour seacast.

Which would be stronger?
Vacuum bagging Coosa Board as the core wood replacement, or pouring seacast in the cavity left by the removed wood?

quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Re: Repair of Wet Wood In Transom

Postby quickenberger » Mon Mar 13, 2017 12:04 pm

I decided to remove the outer skin and it is finally starting to dry out. It may be a good time to just pull all the wood out and replace with something that won't absorb water at all.
Attachments
photo (14).JPG
photo (14).JPG (41.24 KiB) Viewed 10244 times

User avatar
Don McIntyre - MI
Posts: 126
Joined: Fri Oct 09, 2015 4:33 pm

Re: Repair of Wet Wood In Transom

Postby Don McIntyre - MI » Mon Mar 13, 2017 5:35 pm

Wet or rotted wood in the transom occurs when either no, or improper bedding of _any_ penetration occurs in the transom area. This actually can and does occur in the decking area with wood underneath.

When our 21' Outrage was renovated, the shop found transom dry rot. Repaired via opening up the stern. I've witness other repairs to cruisers from the inside; the engines (in this case stern drives) removed and work progressed from the inside. The shop owner used the West Epoxy concept of oversize drilling of, say the engine bolt holes, sealing one side with tape, and pouring in neet epoxy into the hole after creating a "U" shaped dam with tape. Let harden overnight then redrill to the proper size. What you end up with is what the West engineers call an annulus that will not allow water to penetrate into the wood substructure.

If you just replace with wood, and do the above procedure, I'd bet the transom will last for at least as long as you own her, and probably longer.

Regards - Don

quickenberger
Posts: 90
Joined: Sun Feb 05, 2017 8:48 pm

Re: Repair of Wet Wood In Transom

Postby quickenberger » Tue Mar 14, 2017 1:12 pm

Don McIntyre - MI wrote:Wet or rotted wood in the transom occurs when either no, or improper bedding of _any_ penetration occurs in the transom area. This actually can and does occur in the decking area with wood underneath.

When our 21' Outrage was renovated, the shop found transom dry rot. Repaired via opening up the stern. I've witness other repairs to cruisers from the inside; the engines (in this case stern drives) removed and work progressed from the inside. The shop owner used the West Epoxy concept of oversize drilling of, say the engine bolt holes, sealing one side with tape, and pouring in neet epoxy into the hole after creating a "U" shaped dam with tape. Let harden overnight then redrill to the proper size. What you end up with is what the West engineers call an annulus that will not allow water to penetrate into the wood substructure.

If you just replace with wood, and do the above procedure, I'd bet the transom will last for at least as long as you own her, and probably longer.

Regards - Don



This is a common practice in the aerospace industry. Whenever a bolt passes through a composite skin there is a "hard point" created by coring out the foam, honeycomb, or core material and filling with an epoxy and cabosil mix. When cured, the hole is then re-drilled and that allows loads to be transferred through the inner and outer skins and not the core material.
I plan on counterboring the engine bolt holes, drain holes, screw holes for transducers and filling with the epoxy and cabosil mix, then re-drilling like you said above.

Repairing from the outside looked to be less work than going in from the splash well. I left large flange around the perimeter of the cut to taper when reglassing over the dried core.

Someone needs to invent an expanding counterbore so you can drill a small hole on one side of the composite skin, insert counterbore, ream out core material, collapse counterbore and remove particles. Then that pocket can be filled with an epoxy filler that bonds to the inner and outer skin and creates the hard anchor points.

See picture of the deck lid. I removed the chop fiberglass from the hatch and counterbored the holes in the wood where screws or bolts will pass through. Those counterbores will be filled with the epoxy cabosil mix and then the whole underside will be glassed with biaxial cloth trapping the filler in between.
Attachments
photo (6).JPG
photo (6).JPG (43.78 KiB) Viewed 10192 times