Whether you are on land or underwater, a diving knife can be invaluable. On a dive, it is your safety tool, helping you cut through the tangles of seaweed, old fishing nets, ropes or fishing linethat can be such a danger in the water. It can help you dig out that seashell you have found on an ocean floor. Your diving knife may be even more useful out of the water, where it can be used to open seashells, fillet that fish you caught, or repair your scuba gear. When looking for a diving knife, look for:
1) Blade. Most divers find that a 4-5 inch blade is useful without being cumbersome. Beyond length, determine whether you want a serrated blade or a straight blade. A straight blade is good for finer work, such as filleting a fish or cutting fishing line. A serrated blade tends to stay sharp longer and is rugged enough to cut through rope, dense seaweed, and the like. A serrated blade will be good for many diving tasks. If you decide on a straight blade instead, make sure that it is at least curved slightly for more versatility. Or, you may want to look for a diving knife that offers both blades. As well, some serrated diving knives offer a hook or notch for cutting fish line. This can be a good alternative as well.
2) Grip. The grip should be similar in length to the blade for stability. Beyond that, look for a sturdy grip that is no-slip, even under water. Some diving knives are coated in rubber or synthetic materials to improve grip.
3) Materials. Most dive knives have titanium, alloy, or stainless steel blades. All offer stability and durability, and all resist rust and dulling. Choose the material that most appeals to you, but keep in mind that most knives that resist rust and corroding still are vulnerable to corroding if they are not rinsed and dried completely after salt water dives.
4) Knife tips. The tip of your diving knife blade can be either blunt or pointed. Divers who like to fish prefer the pointed tip for butting and fine filleting. Most divers, however, prefer the blunt tip, as it allows the knife to be used in more diverse ways – as a screwdriver, for example.
5) Knife storage. Some diving knives come with sheaths while others fold. Folded knives can fit easily into a pocket but may be harder to open if you wear dive mitts or gloves. Sheathed knives are worn in a sheath on a pocket flap, leg, or deflator hose. While easier to access, sheathed knives may also become cumbersome and can get entangled in seaweed or other underwater obstacles. If you opt for a sheathed knife, look for a sheath that will attach where you prefer. Also, look for sheath with a quick-release button. This button helps you easily access the knife but also ensures that the knife will not slip out of its sheath. When considering knife storage, also keep in mind how you will travel. If you will be traveling by plane you will need to pack your knife in checked baggage.