For recreational boats in Canada there is a legal requirement to have:
"one Canadian approved personal flotation device or lifejacket of appropriate size for each person on board"
But they won't help if you're not wearing it!
Lifejacket's and PFD's:
http://www.tc.gc.ca/eng/marinesafety...ation-1324.htm
Videos from a wave pool. It's amazing how quick people get into trouble. See how fast you can spot the drowning victim:
https://www.youtube.com/user/LifeguardRescue11/videos