Bertram 25. Help me evaluate transom now that keyholes are open

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
ttownthomas
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Bertram 25. Help me evaluate transom now that keyholes are open

Post by ttownthomas »

About a year an a half ago I started refreshing a Bertram 25. I got down to the outdrives after doing a bunch of mechanical work and decided the transom assemblies needed to be replaced. I have removed the transom assemblies and the keyholes are exposed now. The plywood seems ok, but not totally dry. How do I tell if I can proceed without a full transom redo. Here are the pictures:

ImageKeyholes - 1 by ttownthomas, on Flickr

ImageKeyholes - 4 by ttownthomas, on Flickr

ImageKeyholes - 1 (1) by ttownthomas, on Flickr

ImageKeyholes - 2 by ttownthomas, on Flickr

ImageKeyholes - 5 by ttownthomas, on Flickr

ImageKeyholes - 3 by ttownthomas, on Flickr

Fuzz
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by Fuzz »

A few years ago I pulled an I/O out of a Seasport and installed a bracket on it. I was pretty sure I would need to rebuild the transom but to my surprise it was all good. I really wanted to be sure of the transom so I used a hole saw to cut half a dozen plugs out and look at them. If you cut plugs make sure to set the pilot bit short enough not to drill through the outside skin. I would want to know for sure what I had before moving forward.

ttownthomas
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by ttownthomas »

What am I looking for?

fallguy1000
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by fallguy1000 »

ttownthomas wrote: Sun Nov 15, 2020 9:15 pm About a year an a half ago I started refreshing a Bertram 25. I got down to the outdrives after doing a bunch of mechanical work and decided the transom assemblies needed to be replaced. I have removed the transom assemblies and the keyholes are exposed now. The plywood seems ok, but not totally dry. How do I tell if I can proceed without a full transom redo. Here are the pictures:

ImageKeyholes - 1 by ttownthomas, on Flickr

ImageKeyholes - 4 by ttownthomas, on Flickr

ImageKeyholes - 1 (1) by ttownthomas, on Flickr

ImageKeyholes - 2 by ttownthomas, on Flickr

ImageKeyholes - 5 by ttownthomas, on Flickr

ImageKeyholes - 3 by ttownthomas, on Flickr
Awl test. Mushy wood is a redo.
My boat build is here -------->

viewtopic.php?f=12&t=62495

ttownthomas
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by ttownthomas »

Ok...here is more information: I had a survey done on the boat prior to purchasing it. for what its worth the transom passed his tests. It sounds decent when you tap on it but I am a little concerned about the wood at the bottom of the keyholes. it may be a little wet. I guess what I'm asking for is suggestions on how to start the evaluation. What progressive steps should I take so I don't peel back the onion too far. I was thinking I'd start with Forstner bits to expose the wood in various places?

fallguy1000
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by fallguy1000 »

ttownthomas wrote: Mon Nov 16, 2020 8:00 am Ok...here is more information: I had a survey done on the boat prior to purchasing it. for what its worth the transom passed his tests. It sounds decent when you tap on it but I am a little concerned about the wood at the bottom of the keyholes. it may be a little wet. I guess what I'm asking for is suggestions on how to start the evaluation. What progressive steps should I take so I don't peel back the onion too far. I was thinking I'd start with Forstner bits to expose the wood in various places?
Just run a halogen or two about 2 feet away from the hull and feel/watch for steam to rise up out of the keyholes. CAUTION! Do not walk away! Once the system starts to heat up and the water is all gone; it will heat past 212F and catch fire.

Put a couple steam escape holes on the insides of transom on the port n star edges so steam does not migrate to the hull or it can create a blistering environment.

You have to monitor the entire process. Adjust light dostance locations, etc. I did this on a Whaler and got bored and walked away tp do something for like a minute and scorched the boat. Fortunately, I was close enough and smelled it starting to burn. Anyhow, setup a project inside or read or something.
My boat build is here -------->

viewtopic.php?f=12&t=62495

ttownthomas
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by ttownthomas »

is this process used to dry the transom or to evaluate for the presence of steam and therefore water?

fallguy1000
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by fallguy1000 »

ttownthomas wrote: Mon Nov 16, 2020 10:17 am is this process used to dry the transom or to evaluate for the presence of steam and therefore water?
Both. If it stops steaming; you'll know you are dry. You might need to do both sides for a thicker transom. But like I said; you must monitor all the way and too hot to touch means it will catch fire.
My boat build is here -------->

viewtopic.php?f=12&t=62495

fallguy1000
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by fallguy1000 »

Also, the gelcoat will cook faster than the glass side, You don't need to steam it out. By increasing the temperature to above ambient; the water will want to exit by nature. The process should be slow. It took me about 8 hours to get the Whaler dried enough to stop seeing the steam/water vapor exiting.
My boat build is here -------->

viewtopic.php?f=12&t=62495

ttownthomas
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Re: Bertram 25. Help me evaluate transom now that keyholes are open

Post by ttownthomas »

I like the heat idea. Why not sand off the whole inside layer of glass and if it is in moderately good condition use your heat technique to dry it out. Then epoxy over the bare wood and let it soak up the resin? Or does the fact that it is pretty buttoned up allow it to heat up in a way that an opened transom wont allow?

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