Thom,
First of all, use the tool you are most comfortable working with as a rescue knife. If you understand the Hawkbill, it actually has built in safety capabilities. If you need to cut rope, webbing, etc. from an entangled limb, and you don't have a free peice to cut, by placing the blade spine against the victim (edge and point up), you can easily and safely make the cut - any slip will push the edge and point away from the victim because of the curved shape. Whitwater is not a stable platform and there will be slips. Also in the case of a broken limb, or any time the clothing must be removed from the victim, same blade position (spine against victim) and the clothes zip right off safely. If you've been on the whitewater boards, you probably know about the incident on the Ocoee a few years back, where an unconcious paddler had to be cut out of his sprayskirt because the grab loop was inside. A fixed blade was used, an unfortunately cut the boater's femoral artery (legs won't be where you expect them in such a situation). Choke up on handle, cap the spine of a hawkbill with your thumb, and you can make a controled cut around the cockpit rim with only an eigth to a quarter inch of the blade inside the boat. Ever get a splinter from a well used graphite bladed paddle? You'll want a point for splinter removal. Have to unpin a wrapped raft and can't access the valve to deflate one of the tubes - a sheepsfoot blade will make a slice; a pointy knife a smal puncture - less to repair afterwards. Again, use the tools you are most comfortable with, but I've been in some rescue situations and I'm very, very comfortable with a Hawk.