Oil canning happens when a boat is warm and placed on its hull or smasked against something for a while. Teh remedy is fairly easy. leave it out in the sun, hull up, and the plastic memory will take over and it will usually pop out by itself. sometimes you can push around on it and it will pop out. If it keeps happening in the same spot you can actually put some foam between the hull and the seat to give it more support.
I can't say that it is a performance issue except, when you are surfing. It could do two things one cause the hull not to release properly when spinning or just make it slower. Two it represents a soft hull or an area that will not give you good bounce on a wave just because the hull is mushy. It is maily and esthetic thing unless you are surfing a really fast feature.
friend of the fork, knife, and spoon