The SDV program dates back to World War II. Initiated by the Office of Strategic Services Maritime Unit (OSS MU). A “submersible canoe” was invented by the Italians during World War I. The idea was successfully applied by the Italian Navy ("Regia Marina") also early in World War II. The official Italian name for their craft was "Siluro a Lenta Corsa" (SLC or "Slow-running torpedo"). The vehicle was then copied by the British when they discovered the Italian operations and called it the "Sleeping Beauty" or Motorised Submersible Canoe. It was employed by OSS MU during extensive training and exercises, but was never actually deployed for combat operations.