Teacher's Guide: Midget Submarines

Swimmer Delivery Vehicle (SDV)

Swimmer Delivery Vehicle (SDV): Since World War II submarines have worked together with Underwater Demolition Teams (UDTs), commonly known as "SEALsí" (Sea-Air-Land), in a variety of clandestine operations. Carried in a special watertight tank "piggybacked" to a submarine, the SDV gave SEAL teams a greater range of stealth, mobility, and endurance.


X-1: This experimental boat was the first midget sub built for the Navy. X-1 served in a research capacity in extensive tests designed to allow the navy to evaluate its ability to defend harbors against very small submarines. Further tests conducted with X-1 helped to determine the offensive capabilities and limitations of this type of submersible. Because she was never commissioned, the use of "USS" (United States Ship) before her name would be incorrect.

Japanese Type A

Japanese Type A: During World War II these two-man boats, code-named "Mato," were piggybacked to mother ships, usually larger submarines, which carried them to their areas of operation. Matos were used throughout the war and were present at the attack on Pearl Harbor. (Research conducted after the war indicates that one Mato successfully hit USS WEST VIRGINIA (BB-48) with one of its torpedoes.) The two protrusions on the bow, or front, are torpedoes. Contrary to popular belief, Matos were not meant to be "kamikaze," or suicide, subs. This particular boat was part of a 1944 war-bond fundraising effort.

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