thompsondockside.com

I'm writing this as a result of answers I got on a previous post in the Engines forum about motor shaft length. Turns out the problem is a hooked or hogged bottom.

Some people have suggested jacking the keel down, against a strong I-beam or something. This will likely straighten the keel, but I'm sure the ribs are out of whack too. Thus I will perhaps end up with a straight keel but the rest of the bottom still hooked or rippled, possibly more on one side than the other. Any tips would be GREATLY appreciated.

Would it be possible to fill any remaining ripples, or a small hook, with something? It's not exactly classic boat technique, but perhaps auto body filler? I've done car body work before and know I can get it flat and straight with filler, but filler is rigid and the boat flexes: would it just crack out? Can it handle submersion? Is there a product specifically for this purpose?

I am again cross-posting this thread to the Woodenboat.com forum.

You could replace the stringers with stif and straight material, or simply use metal c channel to straighten the present stringers. Strings would be easier to replace than the inner keel. This in addition to the inner keel.

Then use bondo the finish the job.

Or you could do what I did. http://www.aerialimaging.net/john

John, that's a pretty impressive makeover! Beyond what I'm capable of doing, I'm afraid. What kind of boat is it?
Stiffening the stringers might be all that is required. I put on my mask and snorkel and dove under the boat yesterday, and the keel looks straight. The trailer does not have rollers, but rather two carpeted planks on which the hull rests, flanking the keel about 20" on either side. The transom hung off the end, and it looks like the hooks are only in the hull, not in the keel. The left side is worse, hence the veer to the right while underway.
Right now it's soaking nicely-- I turn on the bilge pump every 2-3 days. When I pull it out, I'll block it up and weight the stringers from the inside with concrete blocks, above the hooked area. I'll keep it wet with rags. Is there any worry about rot while doing this? If needs be I can brace & jack the stringers down. When the stringers have straightened, will they need to be stiffened or will they retain their new shape?
Finally, I can finish it off with bondo, but will it stay put or flex and crack out?

Concrete block properly will not do it. Jacks and poles to ceiling might, over correct and let spring back. I've read 2 or 3 months??????

If you are worried about rot, I've read about antifreeze killing rot????

The need for bracing after it's back, don't know, depends on how much is left of old wood.

I would definitely not use auto Bondo for counteracting your hull shape. I believe that it is polyester based, and you should use an epoxy based product, if you choose not to remove and replace the wood.

I have used Petite Protect Fairing compound 7000-7001, (which was very hard to mix).... you could use Smith's Fill-it.... or Smith's lamininating and layup epoxy with some Cabosil filler mixed in.

I have had trouble with auto epoxies on cars, because it hardens so fast... it has gotten brittle and chunked off... or it has not adhered well in the first place. Not only that, it is hard to guess exactly how much of a squirt of hardener is needed, and if you don't get enough, it may be sticky for several days.

Smith's epoxies are mixed 50/50, are very aggressive (stick to), sand well, and will work below the waterline.

Whatever you use, I recommend that you take the surface as close to the wood as possible, and then treat generously with CPES.... Then put one more application of CPES 24 hrs prior to your fairing compound... and then sand with a long board type surface to make sure you stay flat.

Good luck.

I used a 18" or so air powered auto body file to smooth the bottom of my 1960 Cruisers Inc. 202 16'.