My kayak was 15 years old and didn't realize there was a "soft spot" on the bottom until I came back from a kayak trip and found water in it. I bought the patches, followed the instructions and just applied the patch to the soft spot that had a small gap. I let it dry in the sun and just got back from a ride down the river and it was completely dry. I would highly recommend them for their affordable price, ease of use and durability.