Last night on DirecTV (maybe National Geographic channel??) I saw a show that documents a fairly famous ferry boat accident where a ferry out of somewhere in Belgium took off from port without closings it car-loading door, resulting in the capsizing of the boat and the largest death count since the Titanic. Very interesting.
The real interesting part was that most of the deaths were thought to be heavily related to the cold water - just above freezing. One survivor whose story was highlighted was wearing a leather jacket. Apparently the leather jacket took on a life jacket characteristic and helped her stay afloat when others were having trouble staying above water. Many were even pulling down on her legs as they were trying to claw their way to the surface.
I suspect that the leather also had a wet suit effect in that it kept the water next to her torso warm and didn't allow it to flow away as readily as woven coats would.
More info on the event
here