I will own up to making that comment, and accept correction.
I will edit that comment now.
Thanks

I looked at the Cold Water Boot Camp page and it is well done.

A person might not legally be dead at 3 minutes but they will likely be beyond the ability to self rescue.

You might like this page.
http://www.ussartf.org/cold_water_survival.htm

They have a good index of articles on their home page too.
http://www.ussartf.org/index.html

Edit:
Notice also that we are still talking about survival times of less than an hour for a lot of people.