Japanese Type L submarine

The L type submarine (L型潜水艦) submarines were medium sized submarines of the Imperial Japanese Navy (IJN), serving during the 1920s and World War II. The L type submarines were built with Vickers naval technical guidance. All boats were built in the Mitsubishi Heavy Industries-Kobe Shipyard by the contract with Vickers.

Class variants
The L types were divided into four types; L1 - L4

L1 type (Ro-51 class)
In 1916, the Mitsubishi Shipbuilding Corporation got the Vickers L class submarine informations. Mitsubishi which lost competition to the Kawasaki's F type submarines (Fiat-Laurenti type, Ro-1 class and Ro-3 class), bought the license for the L class submarine from Vickers. The IJN hoped an improvement of submarine technologies will be achieved and ordered this submarine from Mitsubishi. Mitsubishi bought 6 submarine kits, and built 2 boats by semi-knock down. The submarine crews were satisfied with the Vickers diesels because they proved to be reliable. The IJN studied the diesel engines and made many variants of similar design, for example: Kampon Mk.24 diesel for the Ro-100'' class.


 * Boats in class

L2 type (Ro-53 class)
The L2 type had minor changes from the L1 type. The changes were:
 * The ship's side torpedo tubes were removed.
 * Changed the batteries. (The L1 was equipped 3 groups, 336 small-sized batteries. The L2 was equipped 2 groups, 224 medium-sized batteries.)


 * Boats in class

L3 type (Ro-57 class)
The L3 type is a license production model of the British L class submarine Group 2.
 * Boats in class

L4 type (Ro-60 class)
The L4 type is a license production model of the British L class submarine Group 3. Their performance was good. The IJN was satisfied with them and stopped the development of Kaichū type submarines for a long time. Later the IJN was not able to regain the technical delay in development of the medium-sized submarines until the end of the Pacific War.
 * Boats in class