The torpedo belt was part of the armouring scheme in some warships of between the 1920s and 1940s. It consisted of a series of lightly armoured compartments, extending laterally along a narrow belt that intersected the ship's waterline. In theory, this belt would absorb the explosions from torpedoes and thus minimize internal damage to the ship itself. Torpedo belts are also known as Side Protection Systems or SPS, or Torpedo Defense System or TDS.