How many people have had to use their knife/cutting tool while diving

[Green_Manelishi]

any opinions as to if a knife is necessary or if other cutting tools (shears, etc) are sufficient?

That depends what you are most likely to encounter. In my experience, cutting 1/2" thick line is easier with a knife.

 

[danpass]

Used a big USD knife to get free of a line wedged between my tank and USD Cam EZ backpack (pre- BCD days), during a night dive in the early 70's. I couldn't see or feel it and freaked out until it could be seen. Just a couple of weeks ago I found two different hooks snagged into two different navigation lines in a quarry (Lancaster RV Park, OH). In the process of freeing the first hook the monofilament got entangled in my 1st stage. My buddy used my titanium coated trauma shears to clear the mess. I carry the shears in one BCD pocket and have a Wenoka Little Squeeze attached to the other BCD pocket. The shears had some trouble cutting through the hooks, so i'm considering some kind of stainless side cutters. The viz in the local quarries is crappy. Following a line and finding a hook via the braille method seems unpleasant.

my regular one rusts (immediately I suppose lol) so I've been considering the Blacktip wire cutters typically found at West Marine. For now it is the naval jelly treatment after the dive.