USS Harder: Rack Patrol is a solitaire, tactical-level, card-driven submarine war game. You take on the the command role of a single Gato-class submarine during WWII, on the hunt for Japanese targets in the Pacific.
The game is entirely card-driven. The operation cards are held in your hand or set on the table as a draw deck. You will be instructed frequently to draw a card from the operation deck in order to determine the outcome of a given action or to gain other information. You earn victory points at the end of a patrol based on the ships you have sunk during that patrol.
A single patrol (round) only takes about 10 minutes to play. However, due to the round/patrol-based structure, and because every patrol is an independent session of play, you can easily play longer, campaign-style games across multiple sittings. The game can be entirely packed up and put away between patrols. Simply record your running score at the end of any patrol and resume the game later.
—description from the publisher