Submarine No.71 (Number 71) was an experimental submarine of the Japanese Imperial Navy completed in 1938. The submarine was capable of a submerged speed of 21 knots, five years before the famous German type XXI

German Type XXI submarine

Type XXI U-boats, also known as "Elektroboote", were the first submarines designed to operate primarily submerged, rather than as surface ships that could submerge as a means to escape detection or launch an attack.-Description:...

 U-boats achieved speeds of around 18 knots. After extensive evaluations the submarine was scrapped in 1941, however the lessons learned lead to the development of the Sen Taka- and the Sen Taka Sho

Ha-201 class submarine

The was a small size-high underwater speed submarine of the Imperial Japanese Navy , serving during 1945. The official designation of the submarine was .-Construction:...

-classes.