Torpedo Attack Likeliest Cause of Shipwreck Military authorities believe that a strong external shock was the reason for the sinking of the Navy corvette Cheonan, on March 26, with a torpedo, mine or depth charge the most likely to generate enough impact. The most likely suspect is a torpedo. â—† Torpedo, Mine or Depth Charge? Torpedoes and mines attack from under the surface of the ocean, while depth charges are thrown into the water from airplanes or ships to hit submarines. Torpedoes travel between 60 km/h to 70 km/h powered by propellers and can hit targets that are between hundreds...