Before Christmas I upgraded my basic SOT kayak to an RTM Disco, again a plastic SOT. What with life stuff and the winter weather, I have not used it; it has been on its side on a rack in the garden. A while ago, while the weather was still cold, I went past it and noticed the plastic was deformed (see attached).

It is a hatchless design so I wondered if the cold air reduced pressure and sucked it in? However we're now in warmer weather and it was still like it. I removed the drain plug as the instructions say to use that to manage pressure; again it hasn't fixed it.

Have I ruined it by not releasing the drain plug before the winter? Is it fixable? If you think it won't affect the handling that'd be a good outcome too.

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  • 2
    You've got oil canning follow the procedure I describe here, you may be able to fix it. Stick the bung back in and leave it in the sun for a while and let the pressure build up put pressure on the affected area.
    – Separatrix
    Commented Apr 22, 2021 at 14:51
  • Brilliant, looks exactly like that. Make it an answer and I'll accept it :) Commented Apr 23, 2021 at 11:35
  • Just to follow this up, we had a really warm weekend, the drain plug was in, and most of the deformation has gone, so thankyou! Commented Apr 26, 2021 at 8:52

1 Answer 1


Known as "oil canning" this is a common problem with plastic kayaks caused by long term storage or tight loading straps on roof bars.

Luckily you have a minor case and since this isn't a performance boat, the effect is entirely cosmetic. However it can be restored with the application of heat and pressure.

The best heat source is a hot sunny day. It's possibly to use a hair dryer or heat gun, but that brings the risk of overheating the plastic and further damaging the boat. With luck the heat alone will be enough to allow the hull to restore itself, but you may need to add some pressure from the inside.

Since you say this is a SOT without a hatch, keeping the bung in place while it's out in the sun will increase the internal pressure likely to a sufficient extent to do the job.

With larger traditional kayaks often weights or a Heath Robinson-esque construction may be required to apply the pressure while keeping the affected area in direct sunlight.

Storing and loading the kayak on edge is advised to prevent the problem recurring.

  • It was stored on it's edge, I wonder if the air from it's factory in the South of France was just too different to the -5 of our recent UK winter! Would you suggest releasing the drain plug for winter storage? Commented Apr 26, 2021 at 11:03
  • @Whelkaholism given it's an otherwise sealed hull, always store it with the bung out so it can breathe.
    – Separatrix
    Commented Apr 26, 2021 at 11:09
  • Okay! I'll wait until it's fully warmed up and reshaped then de-bung it :) Commented Apr 26, 2021 at 12:29

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