My son, who knows little about knives, thought my SRK in SK5 steel was a dive knife and took it spear fishing. Naturally he didn't rinse it so the blade got rust spots in the week or so before I noticed it. When I called him out on it, he pointed out: 1 It has a rubber handle great for wet grip, 2 the sheath's strap is exactly the right size for a diving belt, 3 he found it in the garage with the snorkeling gear. Hard to argue with all that so I let it go. But it made me think. He's right about the sheath and handle, they are good for water. We could use a dive knife for my kayak and spear fishing. For spear fishing it has to do light duty fish cleaning and dispatching. Also psychological shark protection. For Kayak usage it just has to hang out in the emergency bag. It should be as stainless as possible and not too expensive. It looks like the AUS8 OSS or OSI would be a good choice. I hate ordinary dive knives because they're typically 440A and ridiculously thick behind the edge. But AUS8 is one of my favorite steels. Salt water will probably get under the handle and rust the tang, but I'm inclined to use it anyway just rinsing it well. Any suggestions on which one to get? From descriptions, the OSS is hollow ground and the OSI is flat ground. Can anyone confirm?