Spyderco Atlantic Salt (Dive Knife)
There are many knife manufacturers claiming they have a corrosion proof model. Despite this, in my experience most knives turn out to rust in a short time anyway. My first dive knife was supposed to be rust-proof in saltwater. It was the Benchmade Dive Knife X15 Steel Blade with a yellow handle. Unfortunately, it showed some rust after just one day in UK waters.
As I investigated options for a backup knife ("two is one and one is none"), I came across the Spyderco Atlantic Salt with "H1 steel".
According to smarter websites than this one, H1 steel is "a variation of Martensitic Streel (low carbon tool steel) with only 0.15% carbon, up to 16% Chromium (for corrosion resistance) and various small amounts of Magnesium, Nickel, Cilicon, Molybdenum, Phosphor, Sulfur and Nitrogen and is what is called a precipitation-hardened steel" What all that means in the end, at least as far as I can say after diving with it extensively in all sorts of oceans, is that is just does not rust. At all. Amazing.
It comes with a super-sharp serrated edge ("SpyderEdge" - SpiderPig? sorry...), this makes it ideal for cutting everything from fishing nets (only if you do become entangled!), ropes and even rubber. To sharpen, you can either use a diamond hand file or Spyderco's own tools.
The handle is rather long and easy to grip with dive gloves on. It is made out of Fiberglass Reinforced Nylon (FRN), which, according to Spyderco, is "A nylon polymer mixed with glass fiber that is then injected into a mold for making lightweight knife handles." There you have it. In real life, it appears to be extremely sturdy and grips well with both gloves and bare hands when wet or dry. The metal clip has never come off my harness unless I wanted to, still I use a safety leash of about 90 cm (3 feet) to secure it to my harness.
If you are in the US, you might want to check the prices of Knifecenter.com, I have bought from them a few times and so far had no negative experience. Link to the Spyderco Atlantic Dive/Rescue knife at Knifecenter.com
