This is a wargame rule system to recreate simple, fast playing World War Two era submarine actions with miniatures on the tabletop. The rules are for solo or co-op play where the players command the U-boats and the game handles the convoy of allied merchants ships.
Players will roll command dice against their submarine's crew skill in order to take actions. Failed actions will allow the convoy to move for each fail. The U-boats will be in a race to sink or damage as many ships as possible before the convoy makes it safely off the board. It takes skill and luck to maneuver and line up your shots.
The game can also add hazards to the U-boats in the form of escorts and aircraft that will attempt to sink them by bombing, ramming or depth charges if they are detected during play.
Victory is determined by the number of ships sunk, if any, before the convoy exits the board. Submarine players loose if they do poorly or are sunk during the contact.
—description from the designer