There are a few different types of glue that can be used on kayaks, depending on the material of the kayak and what you are trying to attach. For example, if you are trying to attach two pieces of plastic together, you can use a plastic welding adhesive. If you are trying to attach something like neoprene or rubber to the kayak, then you would want to use a contact cement. And finally, if you are just looking for something to hold things in place temporarily, then any type of general purpose adhesive will work fine.