Similar to Battleship, but with more complicated rules. Each player deploys ships in secret on their copy of the mapsheet. Then they try to find all of the enemy ships and destroy them. The basic rules allow for simple movement and firing. The advanced rules cover submerging of submarines, reload time, torpedoes, and depth charges. Ship movement is always announced in terms of direction but not location. Two different mapsheets are included. One for basic play and another for advanced.