The ornamental design for a ship, as shown and described.
FIG. 1 is a right side view of a ship according to the design. The left side view of the ship according to the design is a mirror image of the right side view;
FIG. 2 is a top view of the ship;
FIG. 3 is a bottom view of the ship;
FIG. 4 is a back view of the ship; and,
FIG. 5 is a front view of the ship.
The broken lines illustrate portions of the article that form no part of the claimed design.