Water sail : A small sail sometimes set under a studding sail or under a driver boom, and reaching nearly to the water.

Example:


Taxonomy
Blue Water, Water Sailing, boat, cruisers, sail, sailors, Compass, Florida, yacht, State Farm, sailing, Rally, boaters, Yacht Club, gear, cruising boats, Sailing magazine, around the world.

Defination from the web:
Newsletter of gear and seamanship for offshore sailors.