Scuba Diving Knives are important safety tools for divers and not tools for self-defense. They are not designed for struggling against sharks or with any other marine animal. A divers knife is an essential safety tool that a diver carries just in case the need may arise to cut through an entanglement ( and not cut the corals ) .
Because these knives are always being used in underwater environment, blades are usually made of stainless steel or titanium.
Diver’s knife is usually small in size and because their main goal is to be able to cut lines or ropes.
A dive knife must have a sheath for mounting it on your scuba gear or on your body body. The sheath should keep your knife securely also it should be located in a such way which will let you to get it easily with use of one of your hands , for example on the leg ( inside of the shin ) or on the Buoyancy compensator. Many Buoyancy compensators have special holes for mounting sheath (as shown).
According to an old maritime tradition scuba diving knives must be made blunt , as it does not affects its properties as a knife, but greatly reduces the risk of injury or accidental damage to the equipment under the water.