I overspent on my Kershaw Amphibian (should've known better than to buy it at a mall store, and also to buy Kershaw in the first place since I just don't like their other stuff at all). I think I paid around 70 bucks for it!
I used the attachment on the sheath to put it fast to my PFD for kayaking. It held there well with the round finger screw.
I made the mistake of not thoroughly drying the (crappy) plastic sheath out after rinsing with fresh water one day. Left the vest with the sheathed knife in my trunk for a few weeks or months. Went back and took it out and there were spots of rust all over, and with all the choils and stuff on the knife cut with ridges, there was plenty of space for rust to get a foothold. It had even rusted in the serrations on both sides of the blade. And I had gotten the SALT water off of it!
Anyway, that was my bad. But beyond that, the knife had rusted along the edges of the rubberized grip insert. I investigated it to see if one could take the grip out or off in some way (a la OceanMaster's titanium dive knives which can be disassembled to parts). No go. So I thought about it (NOT enough, as you will read) and decided to remove the grip insert permanently, making this essentially a skeleton-handled knife.
WELL... I used a straight-edged razor to cut off one side of the insert and the other came away easily. THEN I went to put the knife into the sheath and realized... THE GRIP INSERT IS WHAT THE SHEATH CATCH HOLDS ONTO. In other words, the knife will absolutely no longer stay fast in the sheath! It's useless. And I'm a little pissed off at the design of a "dive" knife that cannot really be adequately cleaned, and if not cleaned, de-rusted thoroughly. I feel that Kershaw's design led me to the desperate point of what I did. Didn't force me there, but still sorta led me.
On a related note: I was using Flitz metal polish (which someone somewhere had sworn by) to try to remove the rust from the knife. I could not honestly tell that it was the Flitz or just the green scrubby pad that was doing the rust removing. The couple of times I've used Flitz to remove rust, it didn't work like "magic" like I thought it would. Is there something else, something better, to recommend for rust removal, that won't necessitate using an abrasive pad which will completely ruin the finish of any knife you use it on? I had thought that it was supposed to be so good at rust removal that I could use a paper towel and give a good rubdown and voila! But no such luck.
By the way, the Amphibian never took a very good edge for me, and I can shave with the rest of my Spydercos and Benchmades... A lesson is in there for me somewhere.
And when is Spyderco gonna make a serious dive knife??!