I just heard about a story that a kiter had trouble with his kite and alomost got killed. A knife rescued his knife. His kite came down and he was dragged towards a reef. Somehow his line got tangled around him and he was dragged under water. Luckily he had a knife in his harness and he grabbed it and cut the lines around him.
This puts uo the questions about knives again. I heard that almost every kiter in Hawaii is using a knife?
I think in big waves it is even more important. If a wave hits you and the lines get all over you, I don't want to be in it!
Some have the knives at the leg, some in the back of their harness and other at the side of the harness.
What is the best position to have it?
I think at the legs it is not great since imagine being dragged, the last thing to reach are your legs! the back isn't that great neither, but the side of the harness sounds to me like the best solution.
I have carried a hook knife since I started kitesurfing and for ten years before that while diving. I have never had to use a hook knife in an emergency while kitesurfing yet. If I had to cut my leader lines I would need a knife. Aside from that, I don't favor regular knife use for kitesurfing. They can be easy to drop, if they have a point can injure the kitesurfer or damage something else and are often not as easily accessible as a hook knife. I strongly encourage riders to carry a hook knife. Unfortunately, the hook knife provided in Dakine harnesses is near useless given its placement and means of securing it to the back of the harness. In an emergency I doubt that most riders would be able to get it out in time. I wear mine on my seat harness leg strap.
I've been using the Da Kine Seat Harness for about a year. I've had no problems except access to the hook knife in back. So I took a length of nylon strap and tied it to the knive handle. Then I attached the other end to a ring on the front of the harness. One good yank and the knife is in my hand. Plus, if I drop the tiny bugger it isn't lost in the ocean. To make the strap easier to find, I tied tight knots in it every few inches. I can find it easily and I do give it the yank test periodically. It seems to work great. If you ride in salt water, be sure to take the knife out and fresh water rinse it after use or it will rust out quick. At first, I left it in it's pocket and rinsed it. That wasn't thorough enough. Anyway, I think this is one of many areas the kiteboard manufacturers could improve on product safety. At least Da Kine has a knife and a good design on the snap away pocket. If they'd add a little leash it would be better.