Now there you go screwing up a good, heated, irrational debate with your entailekshual facts! Actually good to hear from you. To be clear, I'm not lobbying for anyone to wear a hockey helmet. The only hockey helmets I'm familiar with were in the mid-1980's and if I remember correctly they were exclusively closed cell foam in a hard plastic shell. From what Greg (GH) said, it appears that some are more like a Bell biking helmet that is designed to self-destruct to absorb impact. That's not practical or recommended for boating.
There's an interesting discussion on helmet testing on:
It appears that kayak helmet certification, in terms of impact absorption, is even less than any of the standards for biking helmets. The CE 1385 certification for water helmets goes further to state that they are designed for up to Class 4 and not for extreme whitewater.
I only jumped into this debate because it seems that a lot of people have bought the marketing pitch from kayak helmet manufacturers without doing any research on the subject. Given the minimal coverage of many top dollar helmets, I actually think most would be far safer with a cheapo Protec that offers protection for the temples and nape of the neck. A helmet the size of a baseball cap, no matter the materials used, offers less than ideal protection.
You may remember Gannon, when we paddle the Gorge last year, a buddy of mine got a pretty good gash on the back of his head that day. I can't remember what brand of helmet his was (he's on a multi-day trip right now) but it was a newer kayaking helmet.