This 2013 calendar honors the World War II U.S. submariners and their
> boats. In World War II American submarines spent 31,571 days on patrol in
> the Pacific, attacking 4,112 Japanese controlled merchant ships with
> 14,748 torpedoes, which resulted in the sinking of 1,152.5 vessels,
> totaling 4,859,634 gross tons, or an average of 329.5 tons for every
> torpedo expended. The loss dates for all U.S. submarines sunk or destroyed
> are listed in addition to other historic dates in both U.S. Submarine
> Veteran and U.S. Navy submarine history.