66-68F will set in hypothermia pretty quickly, you would be surprised, it doesn't take freezing water to do it, just cold water, and water around even room temp will kill you.
I really need to see a map of Lake George were the boat went down. There are so many shallow areas and such.
Like I said in an earlier post I think the people were trapped. It was not about hypothermia or swimming to shore.
It was drowning.
Tragic.