I can guess how it happened, I had my boat in the water for a half hour before I ground mine on a bed of rocks. Aluminum doesn't take to straightening very well. They actually had to add metal to mine and regrind it. You can try carefully heating it but it will still be stressed and I don't know if that's so good on a prop. I got in the habit of carrying an extra prop and a couple of extra nuts and cotter pins in one of the compartments on my boat.