I have repaired a blown gasket with aquaseal. If your going to try it, put a bead all the way down the gasket and fold it over. I used clothes-pins to hold it in place until it dried, then applied another layer over the top. I think it lasted 4-5 trips.
I would suggest coming up with the 25-30 bucks it costs to buy a new gasket, and replacing it yourself. You will have to replace it eventually anyway, and a good seal is important in super cold water conditions (fall and winter boating).