Another good idea for the old fat man who flipped his old wooden Row boat.
A live preserver that will inflate by itself and keep his head and face above the water.
This poor old guy did something wrong, he flipped the boat , and as he went into the water, the oncoming Gunn'l whacked him on his head!
Just as his head went under, he was stunned. He came up under the boat.
He'd have been OK with that. But the bottom of the boat was losing air fast and the 'headroom' under the boat was sinking fast and wound up just at the surface. He was OK, rescued pretty quickly by other Fly Fisher's.
If the blow had made him unconsious, or the water might have been cold enough to stun his thinking, the 'Head's up' style of inflatable might have helped him bob to thte surface. (Maybe he would have held the boat afloat eh?)

He lost everything in the boat though.