A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to six or nine, with little or no on-board living accommodation. They normally work with mother ships, from which they are launched and recovered and which provide living accommodation for the crew and support staff.
Some 80 Japanese Type D ("Koryu") Midget Submarines in a dry dock at Kure, 19 October 1945
Crew of a British X-class midget submarine, part of the British Pacific Submarine Fleet
German midget submarine Seehund, with a torpedo
An Italian CB-class submarine in the Nikola Tesla Technical Museum in Zagreb, Croatia
A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as boats rather than ships irrespective of their size.
US Virginia-class submarine underway in Groton, Connecticut, July 2004
Russian Akula-class submarine of the Northern Fleet, in 2008
An early submersible craft, built by Cornelis Drebbel, propelled by oars
1806 illustration by Robert Fulton showing a "plunging boat"
