Surfboards are very sensitive to heat. Most polyester resin begins to noticeably soften at only 150 degrees. Foam becomes very unstable at about the same temperature. There are surfboards that get amazing twists from improper storage or exposure to heat. The fin and surfboard can be exposed to excessive heat; usually in a car while it is resting on the fin. This fin is not ruined! Heat a large pot of water to 160 degrees. Using tongs, immerse it for about 30 seconds. Pull it out and, using potholders, bend it straight (it should be as soft as salt-water taffy). After it cools it is as good as new.
A heat twisted board can be fixed with offset weights clamped outside the rail on the two high ends of the surfboard. On a warm day, put the board inside of a car. Ad the weights to the appropriate ends and clamp with the screws. Close the car and wait till it gets about 160 degrees inside. Take the board out with clamps and weights still in place. Put it on a set of level saw horses and lower the temperature with cool water. Check the twist. You may have to repeat this process or, if luck is with you, that is it.