Corrosion resistance is probably the number one priority for a dive knife. More important than edge holding. They haven't yet come up with "the one perfect steel" for every knife use. That's why we have so many to choose from. Each one is a compromise. The steel, the blade shape, the blade length, the handle ... everything is a compromise - and you choose which one fits your primary need the best. For working in the yard and around the house, my choice is a Mora Companion Heavy Duty made of high carbon steel. I wouldn't dive with it though.