Preventing or identifying rotten floors

wahlejim

Master Chief Petty Officer
Joined
Jul 23, 2015
Messages
884
Back to the OP, moisture meters are fantastic. If you don't have one or don't want to find one, do the test holes. If those are good, button it all up, but you don't want to be doing that every year.

The one good thing about water is it is relatively heavy. Weigh the boat after you have tested it. Take it to a truck scale as empty as possible, note your fuel level, and get a baseline weight. Make sure it is reasonably close to the dry weight that the manufacturer spec'd. After that, weigh it with the same load periodically and see if it gains weight. When the foam starts to saturate, it will be easy to see.
 

kpg7121

Petty Officer 2nd Class
Joined
Aug 25, 2018
Messages
174
Another culprit in the rot game is carpeted decks. The stuff soaks up & holds water like a sponge. Most boat builders in the 80's were using cheap indoor/outdoor crap which added to the problem. And doing a half a$$ed job sealing decks didn't help either. If you have carpeted decks keep them as dry as you can or rip out the glued down stuff & install snap in carpets.
 

Arronh

Petty Officer 3rd Class
Joined
May 31, 2019
Messages
87
Just updating this. I haven’t done a completely exhaustive test of the stringers, floor, and transom, but I took some core samples up by the steering wheel. On the starboard side, the stringer I could access through the ski locker and flooring above that area were both dry.

On the port side, the stringer was damp and smelly(like dirty socks..gross), but the wood wasn’t rotten at all. I’ve seen rot before, and this definitely ain’t it. The floor above this area was dry.

Also, I bought one of those moisture sensors. I just got it today and haven’t used it.

Since this boat is old, I don’t want to put much, if any, money into it, but this is what I’m considering. 1 Tearing up carpet(I wanted to remove or replace anyway), 2 poking some holes in the floor to, hopefully, dry it out. 3 glassing the holes and putting new resin on entire floor. I have some glass and resin from a different project.

This sound good or is it a lost cause? I’m still trying to figure out how to upload pictures. But maybe I can link a YouTube video.

Thanks.
 

wahlejim

Master Chief Petty Officer
Joined
Jul 23, 2015
Messages
884
I would be hesitant to drill holes and 'dry out' for a couple of reasons.

1) The rot is starting, damp stringers are the beginning, I would put money that the foam is wet. The foam will NEVER dry out no matter how many holes you put in it.

2) Water by itself doesn't cause the wood to rot. Water then exposed to oxygen is what causes it to go. You would be accelerating this process, not slowing it.

Bottom line, you have moisture trapped under the floor and it needs to come out if you want to keep the boat. It will never dry out on its own. The foam is like a sponge. Build a wooden box, fill it with wet sponges, enclose it, and drill some holes in the top. How long will it take to dry out? Will it dry out? What will happen to the wood if exposed to water for that long?

The good news: You seem to have caught it early. You may be able to isolate the areas affected by the water and a small rehab project MIGHT work. The only way to find out is to do small sections of demo until you reach dry, solid wood and dry foam.
 

Arronh

Petty Officer 3rd Class
Joined
May 31, 2019
Messages
87
Thanks. I didn’t pay much for this boat. It’s my first one, so I needed something to learn the ropes. As such, I hope to just get a couple summers out of it. I think I’ll coat the deck, fill the holes, and keep an eye on the transom. I can’t imagine it’s worth my time and money to dig into the floor as I’ve seen what that entails in multiple videos. When done, I think it’ll be time for the junkyard and an upgrade. The boat is over 40 yo, after all.
 

wahlejim

Master Chief Petty Officer
Joined
Jul 23, 2015
Messages
884
The first time out I would plan on a short cruise with just you on the boat staying as close to the launch as possible. See how the boat behaves and handles. One major issue with saturated foam is hundreds of pounds of water weight.

Before you do that, get the thing weighed. Drop the trailer right on a truck scale. It will cost less than $20, probably closer to $10. Compare it to the dry weight spec'd for the boat and see if it is in the ball park after accounting for the extra weight. Weighing it 2-3 times per year will let you know if it is taking on more water in the foam.
 
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