Deep Blue Death

Deep Blue Death is a simple "beer & pretzels" wargame for two players. Each player controls a fleet of submarines and decoys by issuing a limited number of orders each turn. Players must manage their resources carefully to win. Victory conditions depend on the scenario.

The PDF includes rules, counters, scenarios and a map.

From the publisher's website:
In the year 2020 mankind finds themselves with little but submarines after a terrorist attack. Use your sonar to distinguish between subs and decoys. Fire rocket powered torpedoes through the water at 200 miles per hour! Dodge enemy torpedoes with noisemakers or evasive maneuvers. But manage your resources carefully; when you’re out of torpedoes, you’re just a target.