The ornamental design for a sail, as shown and described.
FIG. 1 is a perspective view of a sail embodying the present design.
FIG. 2 is a front view of the sail.
FIG. 3 is a rear view of the sail.
FIG. 4 is a right-side view of the sail.
FIG. 5 is a left-side view of the sail.
FIG. 6 is a top view of the sail.
FIG. 7 is a bottom view of the sail; and,
FIG. 8 is a perspective view of the sail as used with a Laser™ class type sailboat.
The batten pocket portions shown with dashed lines form no part of the claimed design. The broken lines showing the sailboat hull, mast and boom in FIG. 8 represent the environment in which the sail resides but form no part of the claim.
The article is a sail intended to be used with a sailboat.