Recommend me a corrosion resistant dive knife

Well, I don’t really need a dive knife, but I do need a corrosion resistant knife for taking out in the ocean. I’ve got a sailboat and an ocean kayak that I use for lobster fishing. The lobster nets in particular has a ton of lines that could get tangled. After my Leatherman Wave got rusty due to less than meticulous care, I’m thinking that I’d like to get a titanium or ceramic knife.

Is it dangerous to have a pointy knife strapped to your arm or thigh? It would be cool to have the quick release mechanism should I get attacked by an agent from KAOS or have to wrestle a shark. Do the quick release mechanisms work reliably over time, or do they get worn out? Would the sheath stay in place even while moving about on a small catamaran? Is it a good idea to get one with a blunt tip, as to not impale oneself? It would be nice to have a line cutter built in. The knife should be big enough to chop up a frozen mackerel for bait. Cheaper would be better, as I have a tendency to misplace such items and also there is a reasonably good chance of dropping it into the water.

Any of the Spyderco Salt series knives, made with H-1 steel. they use Nitrogen instead of Carbon in the steel, and they do not rust, period

I torture tested one in a hypersaturated rock salt solution, a 2.5 gallon aquarium filled with rock salt infused water, and with an ultrasonic fogger in place to create highly corrosive salt fog

a conventional cheapo “stainless steel” Sheffield knife from Home Depot showed rust spots in a half hour, actual rust in an hour…

the Spyderco Salt 1 I was testing withstood TWO WEEKS in the same chamber before I got bored with it and stopped the test, not a single speck of rust, completely undamaged

Check out . They make fixed and folding knives (both pointy and not) out of dendritic cobalt, which is both non-magnetic and rust-free. I’ve carried one of their folding pocket knives for 10 years and I think it’s great. Right size, no rust, cuts very nicely when sharp and surprisingly well when dull. They also have marlin spikes on the folding ones now, which may be of interest with all the line handling you do.

Before we do any thing else, remember that knives used on boats have not infrequently been known to be lost overboard. Don’t spend more than you would be willing to lose to the briney deep without losing too much sleep.

Check out the Gerber River Series. They are inexpensive enough that their loss is no heartbreaker, they have the kind of “coolth” you mentioned, and will not corrode excessively with just minimal care.

For the record, you are my new hero.

Thanks for the responses.

Pretty cool, but kind of spendy. Owning a knife made out of dendritic cobalt is bound to impress any boat geek.

MacTech, that’s awesome.

Scumpup, those look pretty cool, but like I said, the stainless steel in my experience tends to rust, and even minimal care is usually outside of my capabilities. It looks like they are pretty popular for river rafting, which tends to be a less harsh environment than salt water.

I’m probably going to get this one. It’s titanium, not very expensive, has a linecutter, and folds so I’m less likely to stab myself.

I do a bit of diving, though more freshwater than saltwater. One thing that you might want to consider having for the purposes of cutting lines is a pair of EMT shears. They are generally under $20, and will make quick work of the lines.

I am a scuba diver, and this one is the one I have (and is very popular among divers):
(sorry for the long link)

I don’t know that there is such a thing (within reasonable budgets) that is “corrosion resistant”. I was taught to treat my knife with silicon gel after each use, and it has lasted well for 6+ years. So given proper care, I can vouch for the knife to last probably 120+ dives and counting.

One of the all-time coolest diving knives was the Tekna knife. I still have an original 80’s-production example that I couldn’t bear to part with when I liquidated my collection. Apparently they are back in production, at least sporadically. Made in Italy now too, it seems.
WRT titanium blades knives: they generally aren’t worth a hoot as knives. Titanium doesn’t hold an edge at all. The titanium bladed knives I’ve seen were made either as gimmicks or for people for whom a tool with no magnetic signature was important (e.g. bomb disposal). I’m guessing that inexpensive folder you linked to has ferrous rivets and a ferrous backspring that will corrode without proper care, though the blade may not. Since the knife is going to require care anyway, you might as well get one with a blade that can be made sharp and that will hold that edge through a reasonable amount of use.

The only advice I have to give is get a serrated blade. I have always carried a knife when I sail just in case I need to cut a sheet in an emergency, but it wasn’t until a few years ago that I realized I was always carrying the wrong kind of knife. A non-serrated blade can cut a sheet but a serrated blade will cut it much faster.

We once got an old bouy line wrapped around our prop so I dove over with my knife and tried to cut it loose. I probably could have done it after a dozen or so tries, but after my fifth re-surface for air, one of the crew called out and handed me his serrated knife. It cut through with one try.

Concurred. The only titanium tools I’ve used are for non-sparking environments (it is Not A Good Thing to spark around solid propellant rocket motors) and they’re definitely softer and more flexible than even mild steel much less the tooling grade steels used for knives.

I like the Benchmade River Rescue Knife, which is half-serrated and high carbon stainless (I think it’s still 440C). I carry one for kayaking and small boat sailing, so it gets dunked a lot and doesn’t have any major rust spots; just a bit of discoloration in a couple of places.

Better yet, don’t carry a knife at all. A pair of serrated emergency shears is what I normally carry unless I’m doing wreck diving in which case I’ll go with high chromium tool steel cutting pliers. Serrated is good when it comes to cutting stuff like line or webbing, but I think that having a free edge in the water near BCDs is a bad safety move.


The very best (but not cheap) is a Puma SeaHunter. I do not think they are made any longer but you can find them on ebay, etc. The combo of different edges, extreme quality, and absolute imperviousness to rust* make this a winner.

There’s a collectible quality one now on ebay, I see:

but it will likely go for $300 or so. Note that it is NIB, etc, used ones go for less.

  • I once took mine out snorkling but we had an emergency so I had to throw it in my bag instead of cleaning it. Next season, I was going through my bag and thought “Oh shit!” but there it was, with just a few marks that polished off in a few minutes.