Designed in 1938 it is a Type-A midget submarine 80 feet in length, 6 feet in diameter. The displacement is 46 tons and the hull is made to break down into separate three sections.
The craft is propelled by a 600-horsepower electric motor, driving a pair of contra-rotating propellers. Batteries supply the power but a mother ship is required to recharge.
Range is between 25 to 100 miles based on battery use. The sub carries two torpedoes, each armed with 1000 lbs of explosive.