I have had a Spyderco knife that has miraculously endured 13 years of salty sea kayaking in my life jacket pocket with just a quick rinse after every (most) paddles. It flips out easily with one hand so you can keep your other hand on the paddle. Well worth whatever I payed for it back then.
For multi-day excursions I keep a leatherman in a dry sack. The number of times it has gotten me out of a jam is too much to mention. With a combination of a Leatherman, duct tape and marine goop tp waterproof the tape, there is very little you can't fix.
With great power comes Awesome irresponsibility.