If it is leaking at the laps there is glue or something in there, Take a heat gun and heat it a little it will help seal some of the leaks. Then coat the inside. I used bed liner because it was easy for me to get and it was all under the floor so it wouldnt get walked on. Mine had some leaks on the seams and thats what I did and ended up one leak at the very front of the boat at the V and got it sealed finally.
Steve