Poly hull - dent/loss of shape - repair?

I have a poly boat that I left sitting on its bottom on my garage floor for a couple of weeks in cold weather. I discovered today that there is a bit of a wave/dent in the bottom under the cockpit. I brought the boat indoors today to warm it up. Is there anything I can do to restore the original shape? Or will it return on its own?

I bought a boat that had been sitting on a garage floor and was misshapen. I put it on sawhorses, placed some 2x4’2 and used a scissors jack to return it to the correct (such as it was) shape. Left it for a week and it retained it’s shape after that.

if you can wait for a sunny day
One thing i’ve done is tape a black plastic bag over the dent and leave it in the sun for a few hours. The heated, softened plastic will remember its original shape. If needed, apply a little force with something wedged in place (piece of wood, stiff foam, etc.) to push out the dent.

If its just too cold out there i’d wait until spring rather than try to apply heat. Too easy to ruin the boat, and a dent can wait.

have a friend who uses hot water to get the shape back

heat gun
I fixed an oilcanned whitewater boat with a combination of a heat gun on low setting and a wet hand towel, microwaved to get it steaming hot. I used a hand to press on the inside of the hull as I warmed up the outside.

Probably not worth worrying about
Plastic does that. If it’s a minor one, it’ll pop out a bit come warm weather again. In any case it is not likely to affect the performance. Just don’t store it on its bottom - that’s the weakest part of a poly boat - side or deck are better. And go down and change the position once in a while over the winter.

One thing that deformity does affect over time is how tightly the bulkheads hold. It is typical maintenance to grab something like Lexel from the local hardware store and renew the seals around the bulkheads once or twice a year. Assuming you have the minicell foam bulkheads, they don’t tend to expand when the plastic hull moves so the edges will open up just a little.

It’s very easy to do - more messy than difficult.

Use Blocks to store boat
Find something, rubber, foam, wood, etc. to store

boat off the ground and prevent the condition.

  • Support boat under the bulkheads when possible.

Yea, I know

– Last Updated: Oct-30-11 1:25 PM EST –

This was not my typical storage situation. Two things conspired against me - new boat arrived before I had my storage system set up and I left on a 2 week business trip the next day. This won't happen again - especially now that I see how quickly these boats can lose their shape if not stored carefully. I have a hoist and strap system in place now with the straps wrapping around the boat on its side right at the bulkhead locations.

After I have a few years under my belt I'll probably switch to composite.

Good news is that after about 20 applications of a good hot (microwaved) wet towel the hull is back in shape. Phew - disaster averted.

Thanks for all the input.

Store on the side, carry on J-cradles
If you store your poly boat on its side it will not deform. Also, carrying your poly boat on saddles is another way to deform the hull (especially in hot weather). It’s another reason I feel that J-cradles are the best way to cartop. If you have to use saddles, carry the boat upside down on the deck, which is much more structurally rigid.