1986 Thompson 240 Hard Top - possible floor rebuild

Hello all:

Been around boating for a long time, but never had "older' boats that I needed to do extensive fix up...until now.

I purchased a 1986 240 Hard Top in very good condition. Has a brand new transom put in just last year. The previous owner was very proud of his rock solid floors (especially with all the known Thompson issues). So with previous rotten transom in mind, I look and look and don't find a thing wrong with the floor. That is until I buy it and a three day rain moves in (lots of water in that system) and I am cleaning the water out of the removable carpet....and discover a spot just starting to get soft on the very side to the rear of the front seats. That is exactly the spot where water leaks in on the Thompson's causing all their problems. I really have to press on it to feel it give even slightly, but it IS there. :facepalm:

Boat is in excellent shape for its age, teak looks new and was always well maintained. Last owner was nuts about keeping the bilges as bone dry as possible. Motor has less than 900 hours, everything works and there is $4,500 into the transom by the other guy....so a few questions I need your help with.

1) How long can I get away with it in this condition? I mean does it start to deteriorate quickly once it starts?
2) Is is possible to cut out that section (floors are glassed over, I'll try to post pic tomorrow), replace and glass over, or am I dreaming...and I know to worry about stringers too....
3) Obviously the motor was pulled for the transom repair and now there is a very slight sheen in the bilge water and when its been running high RPM for a while you can get a slight whiff of burnt oil, like if you spilled a little oil during a change. I kinda thought that may have been what happened but I've put about 15 hours on the boat and got the engine nice and toasty...still an oil odor from the engine, but no noticeable leaks and no noticeable oil from the exhaust.

On another note, I also bought a dirt cheap 1990 240 HT primarily for its near perfect trailer, with the intention to pull the motor/out drive, scavenge for parts and junk the hull. However with a hull even nicer than the '86 and all the good info on this site I am thinking of pulling the floor/transom and trying a long resto...What have I got to loose but a little time and burn some favor credits with my buddies?? I have seen many others on this site separate the hull from the top. I assume that's not possible with a hard top so what would you do? Since the hard top is present does that offer enough hull stability so that you don't have to hold the sides together when you yank the floor?

Any pics or first hand knowledge of whats below a Thompson hard top is much appreciated!!

Thanks in advance for all the help

Re: 1986 Thompson 240 Hard Top - possible floor rebuild

I also bought a very clean boat from previous owner that kept it stored inside his shop when not on the water. However, I can tell from some light "staining" below the waterline that it has spent some time in the water. I just found two small spots near the cabin floor where the carpeting is delaminating from what I believe is a stringer running bow to stern. Tapping on these areas indicatea there is definite softness. Made me sick when I found it. There is as of yet no noticeable structural problems, but if I see it spreading I'll have to deal with it.

I had a motor home where I found a little dry rot under the rubber roof where the previous own let a tear go un-repaired. I patched the tear and just kept an eye on it. I did not see much if any degradation over 4 or 5 years of use. Dry rot is a fungus as I understand it and it will spread if not killed, but I think the rate of spread is minimal if you can keep the area dry. I'm in the Pacific NW, so not a lot of humidity to deal with.

If the rest of the floor is solid it doesn't sound like a big deal to me. I would make sure there is no further leaking in that area and go have some fun with the boat this season. Over the Winter pull up that area of floor and see what you've got. Good chance you've caught this early enough you'll be able to do a simple repair. If the area is small check out products that kill the fungus followed by a hardener to bring back the structural integrity. Any of that would be WAY easier and cheaper than completely gutting the hull.

That's my 2-cents anyway...

Re: 1986 Thompson 240 Hard Top - possible floor rebuild

Thanks!