Like submarines, Attack Submarines are stealthed while moving or standing still and invisible to enemy units except for detectors. They are also detectors themselves, capable of detecting hidden enemy units, including enemy subs and land units like Spies. Attack Submarines reveal themselves only when attacking. They become stealthed again when not attacking for a while (roughly 20 seconds). Light Ships and Helicopters have the ability to detect Submarines and are very effective in destroying them.