Answer:

mainsail

Answer	Crossword Clue
MAINSAIL	Big canvas
MAINSAIL	Windjammer sheet
MAINSAIL	Canvas.

MAINSAIL	Part of a clipper.
MAINSAIL	Part of a square-rigger.
MAINSAIL	Schooner feature
MAINSAIL	Schooner propellant
MAINSAIL	What a sane male turns at sea
MAINSAIL	Kin of a topgallant
MAINSAIL	Important item on a schooner
MAINSAIL	Square-rigger's necessity

MAINSAIL	Part of a schooner
MAINSAIL	It's above a boom
MAINSAIL	It's connected to a boom
MAINSAIL	Big part of a ship's rigging
MAINSAIL	Mast canvas
MAINSAIL	Thing attached to a sloop's boom