While Crocodile Dundee may disagree, bigger isn't always better when it comes to dive knives. Regardless of what they show you on TV or in the movies, you will not be using your dive knife to battle sharks, giant squids and crazed eels that have been genetically altered by a mad scientist, or even enemy spies. With the large selection of knives on the market, it may be difficult to figure out which blade is the best. This buying guide will walk you through important dive knife elements so you can pick out the best blade for you.
Many divers carry a dive knife as a tool that can be used in many circumstances. For many people, carrying a knife simply offers peace of mind.
Knives are typically carried by divers in case they find themselves tangled in fishing line, seaweed, or kelp. They are also used to dig or pry during a dive. Interestingly, dive knives tend to be used more frequently on land than underwater. Some of the more common uses of dive knives are to tighten or loosen screws, hammer or pound items, and open scallop shells. People who spearfish also frequently use their knives to cut and prep their prey for the ride home.
A dive knife with a medium length blade 10 to 12 cm (4-5 inches) is typically sufficient for sport and recreational divers. A large blade will typically get in the way and become more of a nuisance than a help. A good guideline to keep in mind is the blade and grip should be almost equal in length. Therefore, a knife with a 10 to 12 cm inch blade should have a 10 to 12 cm inch grip or handle.
Dive knife blades are typically made of stainless steel, titanium, or an alloy. These options offer incredible strength and durability. They resist corrosion and maintain a sharp blade. It is important to note that even though these items are corrosion resistant, the knife blade still needs to be properly maintained, especially after a salt water dive. Blades must be rinsed in fresh water and allowed to completely dry outside of their sheathes (or left unfolded) once the dive is complete. For how to keep your scuba diving knives in top shape, please see Dive Knife Care.
There are two types of knife blade: serrated and straight. Serrated blades are jagged (like a bread knife or a saw) and are very good for cutting through things like fish bones, rope, and other tough materials. Serrated blades tend to stay sharp longer than do straight blades. Straight edges are ideal for finer cutting tasks, such as fishing line. If you choose a knife with a straight edge, it is recommended to find one that is slightly curved.
Some knives offer a straight blade or a serrated blade; it is also quite common for dive knives to offer both blades at the same time. Additionally, some knives have a notch or hook in the blade that makes cutting items like fish line very simple.
Your knife's grip (or handle) should be comfortable in your hand. If you wear gloves while diving, make sure you can maintain a steady and firm hold on your knife's handle. Some grips are purely metal, while others are metal coated with rubber or a synthetic material to increase the diver's ability to safely grasp the knife.
Dive knife tips are either pointed or blunt. Blunt or chisel tips tend to be the better choice for recreational and technical scuba divers, simply because the blunt area can be used as a screwdriver and pry more safely than a pointed tip can. Plus you're less likely to stick yourself.
If you spearfish, a pointed tip is the better choice because the tip can more easily butt the prey.
You have two options for knife storage — fold the knife or sheath the knife.
The first option is to use a folding knife, in which the blade folds into a groove in the handle. A folding knife is good for those who are concerned about the knife being cumbersome or a potential for snaring unwanted items (such as fish lines and kelp) because they can be stored in a BCD pocket and retrieved safely at any time. The downfall to folding knives is they aren't easy to open when wearing dive gloves or mitts.
The other option is to store your knife in a sheath. Sheathes attach to either the diver's leg, BCD pocket flap, or BCD deflator hose. Not all sheathes offer all mounting options, so make sure the sheath that comes with your knife will mount where you want it to. Some sheathes are equipped with a quick-release button; a quick-release keeps the knife secure in the sheath until the button is depressed. This keeps the knife from accidentally slipping out of the sheath at an inopportune time.
Many new scuba divers buy a BIG knife and strap it to their leg because that's what they see those spearfishing do. Then they find out that a smaller knife is more useful, and that you can't alwys reach your leg in an emergency. Leave such knives to the spearos.
A more compact knife is a better choice. While some people stash their knife in a BC pocket, strap it to their upper arm, or mount it on their inflator hose or BCD, more experienced scuba divers prefer to mount their dive knife on their harness or BCD waistband. But that's not possible with all BCDs and knife sheaths.
Divers who do lots of shore and pier dives oftwen have a dedicated separate line cutting tool to more easily cut away fishing lines and other snap hazards.
If you are traveling by air to a dive destination, do not pack your dive knife in your carry-on luggage! Airport security will confiscate your knife. Instead, pack your knife in your checked luggage.
Another option to taking a knife on vacation is taking a line cutter, which is a less ominous looking tool that can perform many of the same tasks that a knife can.
IST Proline 7 cm Tech Diving DIR Knife with Sheath - Chisel Tip
RRP: $40, Our Price: $35, You Save $5 (12%).
This is our favourite small, compact, stainless steel dive knife. It has a cutting edge and a serrated edge with line cutter combined with a chisel tip all in a webbing sheath. Everything you need!
Tusa FK-11 Blunt Tip Diving Mini-Knife
RRP: $58, Our Price: $52, You Save $6 (10%).
This is our best selling dive knife, because of its multiple mounting options. It can be fixed with a stainless steel clip on your BCD, or with the includeed hose keeper on your gauge or inflator hose.
Ocean Design Predator SQR 420 SS Dive Knife - Chisel Tip
RRP: $49.50, Our Price: $45, You Save $4.50 (9%).
Considered by some to be the ultimate compact BCD or safety knife for scuba divers. The chisel tip blade is made from super strong 420 Stainless Steel. The Secure Quick Release (SQR) locking mechanism is the most effective available today.
Trident BC Titanium Knife - 75 mm blade
RRP: $175, Our Price: $158, You Save $17 (10%).
This is our favourite small, compact, titanium dive knife. It has everything you need in a safety diving knife and is made from high quality, corrosion resistant Titanium. Both Lloyd and Peter use this divers knife.
Ocean Design Predator SQR 420 SS Dive Knife - Pointed Tip
RRP: $49.50, Our Price: $45, You Save $4.50 (9%).
The ultimate compact spear fishing kill knife. The pointed tip blade is made from super strong 420 Stainless Steel. The Secure Quick Release (SQR) locking mechanism is the most effective available today.
Ocean Design Apollo SQR 420 SS GB Dive Knife - Point Tip
Our Price: $79
A popular choice with spearos, plus commercial, military, and rescue divers. The Secure Quick Release (SQR) locking mechanism is the most effective available today. The neoprene leg harness provides comfort and automatic compensation for wetsuit compression.
Tusa X-Pert II Titanium Dive Knife - Pointed Tip
RRP: $224, Our Price: $202, You Save $22 (10%).
When only the best will do, this is the spearfishing kill knife you want. It's made from high quality, corrosion resistant Titanium. The knife has a serrated edge and a line cutter on one side with a full straight edge on the other side.
Some divers prefer a dedicated Line Cutter instead of, or in addition to, a dive knife. Most line cutters feature both a cutting hook and a serrated cutting blade. Serrations create a semi-saw on the blade that is ideal for an aggressive cutting action on cable or cord. There are numerous activities from scuba diving to parachuting that require an emergency cutting tool as a mandatory piece of equipment, to be carried on every activity specifically for self rescue, or for the assistance of others.
Mares XR Hand Line Cutter Ceramic in Pouch
RRP: $80, Our Price: $72, You Save $8 (10%).
This Line Cutter in Sheath was developed for divers, mariners, mountaineers, extreme sports adventurers and rescue service providers who demand a tool that delivers a swift, safe, efficient cut.
M-Cut HRC52 Titanium Safety Knife Line Cutter
RRP: $65, Our Price: $59, You Save $6 (9%).
This titanium line cutter is at the forefront of Emergency Cutting Tool (ECT) dynamics and design. It never rusts, keeps a sharp edge, and cuts up to 30 mm diameter rope. No maintenance required and the blades never need changing.
Reef Line Single Blade Line Cutter with Sheath
RRP: $23, Our Price: $21.50, You Save $1.50 (7%).
This line cutter is sharper than a standard dive knife and uses a marine grade stainless steel blade that can easily cut thru braided line, monofilament or any other line entanglement. The blade is easily removed for cleaning and replacement.
Some ocean divers also like to have a pair of Shears for use in cutting fishing line, fishing nets, rope or wire.
Trident Stainless Steel EMT Shears in Pouch
RRP: $46, Our Price: $42, You Save $4 (9%).
These shears easily cut through line, net, rope, kelp, and thin steel cable. This product works well in emergency situations where a knife might not. The shears have Blunt Tips, so you need not worry about accidental puncture or tearing when cutting.