If you watch the average recreational diver swim over a reef, you will notice that he or she tends to stay so far away from the coral that it is a wonder he or she manages to sees anything. This is actually a good thing, though. Why? It’s because the average recreational diver’s body position is so poor, and his or her body is festooned with so much dangling crap, the closer he or she gets to the reef, the greater the risk that the coral this person does not kick to death will be clobbered by some dangling piece of gimmick gear.
This is a luxury cave divers cannot afford. Cave divers must be able to pass within inches of the bottom without their equipment stirring up sediment or becoming entangled in guidelines. This is why cave divers take a very different approach to carrying accessory equipment than recreational divers do.
Knives provide just one example. The typical recreational diver carries the equivalent of a Roman short sword strapped to his or her leg — a perfect invitation to guideline entanglement. The irony is that, despite its size, odds are this "knife" is far too dull to actually cut anything (it would be a potentially lethal weapon in a street fight, though).
Cave divers carry something much smaller in the way of a cutting tool. The “weapon” of choice will either be a ground-down pairing knife or a parachute line cutter, carried in a sheath on the left side of the waist strap (you have to look close or you may miss it). This tool will most likely do a poor job of causing entanglement. In fact, about the only thing you can rely on it for is to cut guideline — quickly and cleanly — when needed. (Who’d have thought?)
Recreational divers often clip items such as slates, surface signalling devices and game bags to the very fronts of their BCs — the spot from which these items will dangle the most and present the greatest risk of entanglement. Cave divers, in contrast, tend to put items such as slates, tables, clothespins, line arrows and guideline spools in their dry suits’ thigh pockets, where these items are not only easy to find and get to, they are also very unlikely to present any risk of entanglement.