Ko-hyoteki class submarine

Type A Ko-hyoteki-class submarine, No.19, grounded in the surf on Oahu after the attack on Pearl Harbor, December 1941
Class overview
Operators:	Empire of Japan
Completed:	101 1 × First prototype 2 × Second prototype 46 × Type 'A' 5 × Type 'B' 47 × Type 'C'
General characteristics
Type:	Kō-hyōteki kō-gata (甲標的甲型?, Target 'A', Type 'A') class midget submarine
Displacement:	46 long tons (47 t) submerged
Length:	23.9 m (78 ft 5 in)
Beam:	1.8 m (5 ft 11 in)
Height:	3 m (9 ft 10 in)
Propulsion:	192 trays of two two-volt cells each,  136 trays forward  56 trays aft 1 × electric motor, 600 hp (447 kW) at 1800 rpm 2 × screws counter-rotating on single shaft  leading prop 1.35 m diameter, right-handed;  trailing prop 1.25 m diameter, left-handed
Speed:	23 knots (43 km/h; 26 mph) surfaced 19 knots (35 km/h; 22 mph) submerged
Range:	100 nmi (190 km) at 2 kn (3.7 km/h; 2.3 mph) 80 nmi (150 km) at 6 kn (11 km/h; 6.9 mph) 18 nmi (33 km) at 19 kn (35 km/h; 22 mph)
Test depth:	30 m (98 ft)
Complement:	2
Armament:	2 × 450 mm (17.7 in) torpedoes, muzzle-loaded into tubes 1 × 300 lb (140 kg) scuttling charge
Notes:	Ballast: 2,670 kg (5,890 lb) in 534 × 5 kg lead bars

The Type A Ko-hyoteki (甲標的甲型, Kō-hyōteki kō-gata^?, Target 'A', Type 'A') class was a class of Japanese midget submarines (Ko-hyoteki) used during World War II. They had hull numbers but no names. For simplicity, they are most often referred to by the hull number of the mother submarine. Thus, the midget carried by I-16-class submarine was known as I-16's boat, or "I-16tou."

This class was followed by: Type B (甲標的乙型, Kō-hyōteki otsu-gata^?), Type C (甲標的丙型, Kō-hyōteki hei-gata^?), and Type D (甲標的丁型, Kō-hyōteki tei-gata^?), the last one better known as (蛟龍^?).