Interesting info about your friend, BUT I find the above information about spinal injury lacking any sound basis in research or analysis. Either your friend and his buddies defied the laws of physics (according to you) or the information is incorrect about water ditchings.

Jeff,

 

I agree with you on this. I tooks some coursework in biomechanics during my undergraduate degree and did quite a bit of research on lap belt and lap belt/ shoulder harness injuries as well as acceleration tolerance of various parts of the human anademy. I recall internal organ damage reports from improperly installed lap belts and sternum/rib joint damage from double shoulder harness use without an H strap. But, I didn't find even one report of a "snapped spine" resulting from use of a seat belt. That's not to say this has never happened, but I think it is rare at most. I think other life terminating injuries are very likely to occur prior a snapping of the spine in this scenario.

 

Rob