Submarines

The submarine is moving ship below the water surface, is generally used for military purposes and interests. Most of the Navy owns and operates a submarine although the number and population of each country is different. Besides being used for military purposes, the submarine also used for science sea and fresh water and to serve in depth is not suitable for human divers. 

German submarines were popularly known as the U-Boat is a summary for Unterseeboot, ranging commissioned in World War I as a lethal weapon systems for the Navy's opponents all the more so in World War II. So known as U-Class. In addition to Germany, a country that uses the popular submarine as a major force navy was the Soviet Union / Russia 

One of the other aircraft is diving diving bell.