Scuba knife/knives

[g1138]

Prying open sea scallops on rocks and cutting the meat out is the only application I've found. Though if you know of a better way to extract scallops from their shells without taking the whole exoskeleton (there's a lot of life that grows on the shells, seems a waste to destroy that too) I'm all ears!

Ahh yes, but you don't need a big knife for that though

 

[mathauck0814]

Ahh yes, but you don't need a big knife for that though

Dunno about that. Some of the scallops we dig out can have shells the diameter of a soccer ball. My knife of choice is only about 6" total length (3.5" blade) but I have definitely found some that were too big for my tool.

In any case - you don't need to spend much on a knife and they're fairly disposable. I try not to spend more than $10 on a cutting utensil, regardless of the size or form factor (sorry for the hijack)

 

[DivemasterDennis]

After going through the "5 inch blade knife strapped to my calf" period, during which I did some kelp diving, I settled in long ago to a 3 inch blunt end knife that is retained snugly in a sheath that mounts on my bcd and is easily accessible and returnable. I have one on each the bcds I use regularly (3). It has proven adequate to cut a line, to dig in the mud, and to bang on my tank to get another diver's attention. It can cut a sausage, spread peanut butter on a sandwich, cut up an apple, and anything else I need a knife for during or between dives. Since you don't have your own bcd, you will be glad to know that knives this size will come with forearm or calf mount straps. Get a dive knife, not some other tool not designed for underwater, especially under saltwater, use. It will last a long time and in the end your save money with quality, long lasting equipment.
DivemasterDennis

 

[Doc Harry]

A knife is just a disposable tool that you will use as a hammer/knife/prybar/screwdriver and also as a bottle opener after the dive. Do not spend alot so you will not be disapointed when you loose it in Davey Jones Locker. Shop ebay and pickup something used, most are bairly used. They can be had for $10

...or rusts at the hilt and breaks.

Same with EMT shears. 10 for $10 on e-Bay, throw each one away after about 20-30 dives.

4-inch pointed knife and EMT shears is what I carry.

 

[cmburch]

Not a good idea to strap a knife to the calf. California freedivers have got entangled in kelp.

Scallops can use a flexible butter knife while in place. Jam shell open slightly (blunt tip knife, old screwdriver, etc. Check state Regs for tools allowed) Use flexible knife to scrape attachment muscle from shell.

I use a knife for spearfishing. I normally strap it to my arm. I might make a pocket on my wetsuit for it. Once I had it on my waist belt and broke the sheath on a rough rocky exit.

Rig or BCD may be best since do not have to remember to bring it since it is always attached.

I would stick with a knife meant for saltwater and a secure attachment and sheath such as a full nylon/Velcro closure so it will not get lost on the first dive.

As mentioned on this thread. A colorful lanyard. I tie some bright cord. Tuck cord between knife handle and sheath when not in use. Slip my hand through it to prevent losing it. If dropped bright color may be seen. Always put name and telephone number on gear so it can be returned if someone finds it.

 

[JamesK]

I hate big dive knives. I have no need for them. Here is what I use.

On my shoulder strap of my sidemount harness.
Eezy Cut Trilobite Line Cutter [trilobite] - $24.95 : Cave Adventurers!, We will NOT be undersold!!!

In my thigh pocket
Dive Rite Titanium Shears with Daisy Chain [AC3212] - $24.95 : Cave Adventurers!, We will NOT be undersold!!!

On my waist strap. I make my own for these, and use a mini mag light sheath for them as I had a bunch laying around.
Oxycheq Stainless Steel Line Cutter [ROT-02-03] - $20.00 : Cave Adventurers!, We will NOT be undersold!!!

I really can not think of a reason I would need anything bigger for the diving I do. Now If I was spear fishing I might want something slightly larger.

 

[divin'dog]

I agree on the short knife with blunt tip as a tool. However, I bought this Dacor knife when first starting out and not knowing better...
DACOR Japan Japanese Diving Knife Tool | eBay

I have several knives, pointed, blunt, shorter, SS, Titanium, and always come back to using the Dacor for NE diving... I don't know why? But I like it and it has served me well as a tool. Of course, I take some crap from dive buddies but that comes with the territory. I prefer it over all my other knives. I also carry shears.

One way to ensure keeping a knife around a long time is to make a wrist lanyard and use it! Obviously, it's a entanglement feature if left to dangle so I always tuck it into the sheath or loop it back over the sheath with some stretchy cord to keep it out of the way. A stretchy cord will allow me to tuck it away or quickly undo it and easily slip my hand through the loop so it is around my wrist before taking it out of the sheath. Nothing like getting tangled then pulling out your knife to watch it sink slowly out of grasp! That could ruin your whole day...

 

[oldflounder]

My first purchases after OW were a compass and a knife. We have a lot of fishing line where I dive and the compass is a no brainer unless you want to do a lot of yo-yo diving to keep track of where you are. Try night diving without one. I tried the knife-on-the-calf position but it does get caught on seaweed, etc. Also, try to resheath that knife after you have taken it out. If you dive in a bathing suit - no problem - but when I have a lot of gear on underwater I have tunnel vision with the mask and can't see most of my body. I find it impossible to put the knife back in the sheath first try by feel. Instead, I just use a standard 4" blade, short handle dive knife that I ziptie to my bcd hose near the end. This is my emergency knife. If I were to ever take it out, I would have it in front of my face when I put it back. I also carry shears on my waist and wire cutters in a pocket in my bcd - [1] ocean fishing gear many times has a length of steel leader a knife won't cut and [2] my big fear is getting one of those large lure hooks embedded in me while it's embedded in something else - this almost happened to me once so ever since I carry wire cutters. I carry a $4 lobsterman's knife in a sheath in my bcd pocket for prying/digging. This knife does a great job of cutting lobster rope if I ever needed to. At times I may have my cutting tools on a retractor so that I can pull them out where I can see them.

You will probably have several types of cutting tools before too long. It depends where you dive and what your local sites require. Luckily where I dive we don't have nets to worry about. Start off with something cheap because you will probably lose it within a few months. Save the $150 SEAL survival knives for later in your career.

 

[victorzamora]

Here are the two that I carry. The reasons why have been covered pretty well so far. Z-cutter on my left chest strap, still haven't found the perfect spot for the knife. Both have held up well to water, but have yet to be in salt. Benchmade Hook and Blunt-tip Knife.

 

[Malpaso]

I'm new to diving, but not new to bladed objects. I carry a Spyderco Salt, a Benchmade 8 reviewed here: http://www.scubaboard.com/forums/knives-cutting-tools/396636-cutting-tool-comparison-test.html and EMT shears.