Outrigger canoe sailing off Dobu Island, D'Entrecasteaux Islands, PNG
The Melanesians have been building and sailing outrigger canoes long distances for thousands of years and this photos shows a good example of one of their double ended sailing outrigger canoes. It has a boomed lateen rig and this, combined with the double end, means it can be sailed in either direction. It is steered by using the paddle as a rudder (see the technique at large sizes). The sail is made of some kind of polypropylene.
Another view of the canoe and other Dobu Island photos can be seen here: http://goo.gl/VXOdw
Re the comments about perspective, I was standing on the deck of our ship when the outrigger sailed by.
250 mm, 1/250 sec, f 11, ISO 250