Wow I didn't realize so much could go wrong while on the water. What tools would anyone recommend to keep on hand while out in the water to be able to make emergency repairs so one doesn't get stranded or forced to use just the paddle so far from shore? I usually keep a toolbox in my truck for emergencies and I would like to do the same with my Hobie.
I'm a noob in general, but so far the only on-the-water problem I've had needed only a good needle-nose pliers, which I had in my fishing kit. The brass nut that I had to loosen was tight enough that I might not have been able to do it with just my bare fingers. The rest - pulling the fin down so it would go back on the mast - was just a matter of muscles.
Overall, it doesn't seem like there's a lot that can go wrong on a kayak, mechanically. Rudder or drive damage is about it, and so long as you've got your paddle you should be at worst inconvenienced.