CIA Semi-Submersible

CIA designed and manufactured a two-man semi-submersible in the 1950s. It carried no weapons, was cramped, had limited endurance, and required a "mother ship" for transport and recovery. However, the vessel could approach areas ships could not.

The semi-submersible was small and quiet. The craft was made of wood and aluminum, with plywood sheathing on bottom, sides, and deck. This construction made sonar or radar detection unlikely. The semi-submersible could be sunk - without personnel - in depths of up to 30 feet. After sinking, it could be left underwater for periods of up to three-to-four weeks. When running in the "deck awash" position, it was almost impossible to see.

Its speed semi-submerged was up to 4.7 knots; its cruising speed was 4.1 knots, and its slow speed was 2.5 knots. With a range of about 110 miles, it could carry 2-to-3 men and 120 pounds of their equipment.