Protect yourself from the sun.
Marshall Islanders invented this fine sun hood from a t-shirt. They call it "ninja style".
Here seen on the skipper of the chase boat of the 2000 national sailing canoe race at Majuro, Marshall Islands.
Just look out through the neck hole and tie the sleeves behind your head.
You're all set for a day on the water.
Works equally well covering mouth and nose or exposing them.
2nd picture is me with my own sailing canoe on an outer islet of Majuro Atoll.
A small or child's t-shirt is all you need, but any t-shirt will do.