There has been no shortage of debate on the subject of whether a diver really needs to carry a dive knife. Many against, argue that a dive knife serves no real purpose, other than to make the wearer feel more like an international spy. Also popular is the misconception of a dive knife being carried as protection against marine life which is very far from the truth.
What is a dive knife?
A diving knife is an emergency tool, to be used only when needed and not to be used as a weapon. Just like the airbags in your car, or for that matter the safety sausage or whistle on your BCD; you may not use them, but you’re always so much better off just having them there.
Why you need a dive knife
To aid yourself or your dive buddy in case of emergency
The primary reason for carrying a knife on a dive is to free yourself or your buddy, should you get tangled in the ever increasing amount of fishing line – such as that cast from a high end spincast reel – or net strewn around the ocean each day. A diver getting caught in fishing line is definitely not uncommon, and most who have escaped this predicament will never again consider diving without one. For those of you that dive in and around kelp forests the possibility of getting entangled in sea kelp is another very good reason for having a sharp knife handy.
To help free marine life
Several divers have used their knives not just to free themselves but to help free marine life trapped in stray fishing line or nets. A handy knife can also serve as a great anchor to the sea bed in heavy current to prevent you from drifting away when your hands cannot get a purchase on any rocks or outcrops. Lastly, even though you may never find the need to use your dive knife (and thankfully so), a knife could simply be used as a good ‘tank-knocker’ for getting your dive buddies attention underwater.
There is argument that a sawing away at rope or fishing line underwater with a knife is not the most effective way to free oneself in an emergency, which is why recently shears and line cutters have been increasingly favored over knives. Both are pretty cheap and work better than a knife on fishing line and heavy rope.
However at the end of the day, it is always better to carry along with you at least one form of cutting tool, rather than be caught up in a situation where you wished you had one.
