My question is: what good does 3 hours in freezing water do if you cant survive for 30 minutes in freezing water??
Any time you end up in the water floating is better than sinking. Effort and energy not spent struggling to keep your head above water can be used to self rescue. The idea is to get out of the water as fast as possible, open water or if you’ve gone through the ice. Manufacturers provide info about how long the clothing will keep someone floating to provide confidence that the clothing will do that job of keeping you floating long enough to get out of the water. If you stick around to test the 3 hour claim…you’re a popcicle.