If you have only been using stainless screws and bolts to attach accessories to your kayak, you are missing out on the easiest solution, a plastic rivet. The tri-grip rivets are the best.
Using plastic tri-grip rivets make it much easier to attach almost anything to your kayak. Simply drill a 3/16″ hole, insert the rivet through and use the rivet gun to tighten and ‘pop’ the rivet.
The tri-grip design will provide ample backing behind the plastic kayak hull for support. Unlike typical aluminum or steel rivets, the tri-grip spreads out further away from the hole.
Here are a few videos to get the idea across.
Rivets can be found at your local kayak shop and they work with almost any rivet gun. If you need rivets you can buy them online too and save yourself the gas money.