Hull bottom "oil canning"

[Jackrabbit]

Hi all,

Just hauled out "Restless" today and noticed that the hull bottom in the way of the trailer bunks have developed concave "dents" , both port and stbd.   I don't think it has anything to do with any impingement on the bunks during haulout, as thre are no indications of scrapes or anything like that on the bottom paint. I've never experienced this before - believe its called "oil canning" (?) - is this something others have seen with their 19s, and will the hull eventually regain its shape? Hull seems very flimsy at this point and flexes a bit when I push with my hand.   I wanted to push the "dents" out from the inside, but unfortunately they occur about at the aft end of the quarter berths, the inside of which is not readily accessible.

Burton

[BobK]

Is your boat sitting on the keel?  The keel should support the boat's weight and the bunks are there for stabilization.

BobK

[Jackrabbit]

Yes it is.   It's been quite cold here, with frost the last few nights.  I was wondering if it is somehow a temperature reaction, or perhaps the bunks impinged on the hull at those points while I was hauling out, though I didn't do it any differently than in previous years. 

If it doesn't eventually pop back on its own I'll have to do some surgery in the Spring, i.e., cut open an access in the bunk tops, remove the buoyancy foam, and try to push it back into shape.  Then I'll fiberglass tab in a semi bulkhead to stiffen the area, as it seems very flimsy.

[Damsel19]

You want to lower the bunks so the weight is bearing more on the keel. The longer the fiberglass is deflected the more likely it is to take a set.  You might build some tempoary supports so yo can drop the bunks free of the hull and observe what happens.