Scuba diving – The dive knife
Regardless of which type of scuba diving you’re interested in from wreck diving and cave exploration to simply taking nice tropical fish pictures a dive knife is recommended as a helpful and vauluable accessory. Since humans can’t breathe underwater something as trivial as getting entangled in stray fishing gear can be a life threatening situation if you’re not carrying the right safety equipment. When taking tropical fish pictures you may for instance become so absorbed by your task that you don’t notice that large ghost net stuck on the outside of the ship wreck where the most spectacular lionfishes are playing peek-a-boo with your camera. In such a situation a good dive knife will help you free yourself from the net before things get critical.
The two most important things to think about when buying a scuba knife are:
- Make sure that you get a scuba knife that is right for you and your diving style.
- Make sure that you know how to use the kind of dive knife you choose to get. If you don’t know how to use your dive knife correctly it can cause more bad than good.
Below you will find info on how to choose a knife that suits you.
What size should the knife be
Generally speaking, dive knives can be divided into three size groups: standard size knives, mini knives, and big knives. The standard size is 4-6 inches (10-15cm) and a standard size knive can be comfortable mounted on your arm or leg. Make sure the handle is large enough for you to grip without much ado. A mini knife will have a 2-3 inch or 5-7.5 cm blade and can for instance be worn clamped onto a hose due to its petite size. They can however be hard to use wearing gloves due to their small size. Always test the handle prior to purchase. Big dive knives have blades that are 5 in / 15 cm or longer and can be a tad cumbersome to handle underwater, especially for precision work. When scuba diving, big doesn’t automatically equals better so only get a big scuba knife if you know that you will be doing things underwater that actually require a big knife.
Material
Most dive knifes are made from titanium or stainless steel. Titanium knives tend to be the most expensive choice, but are on the other hand extremely resilient to rust and other types of corrosion and a good titanium knife will stay sharp for numerous dives. A stainless steel knife will on the other hand be more susceptible to rust and corrosion, but you can counteract this by rinsing it off in freshwater after each dive and leave it to dry completely before putting it back in its sheath. It is a good idea to coat it with oil or silica.
Should the knife have a serrated edge?
A serrated edge is ideal for cutting natural fibres such as hemp ropes and kelp, while a straight edge will be more apt at cutting artificial materials like nylon ropes and monofilament fishing lines. If you decide to go for a serrated knife, ideally pick one where the serrations run almost the entire length of the blade to make it possible to get a nice sawing motion going when you need to cut something. The best choice is usually a knife with a serrated edge on one said and a straight one on the other.
Should I choose a knife with a sharp tip?
A blunt tip is better for the avarage joe diver while a sharp tip can better for divers planning to is it while spear fishing. A sharp tip will easily break if you try to use your knife to hack, chisel, pry, dig or similar. A blunt tip is a lot less likely to end up damaging your scuba gear than a sharp tipped one.
Should I chose a knife with a cutting notch?
Dive knifes should always have a cutting notch because that makes it much easier to cut small lines.
