This year marks the 100-year anniversary of the United States Navy Submarine Force.

The first successful submarine demonstration took place off the coast of Mount Vernon, VA, in 1895 when John P. Holland showed how his internal combustion, gasoline powered submarine, Holland VI, could make submarines an effective and sustainable combat force. The navy purchased Holland VI for $160,000 on April 11, 1900 and commissioned it into the Navy, marking the birth of the United States Navy Submarine Force.

Since then, the submarine fleet of the United States Navy has grown steadily in size and efficiency, proving itself indispensable in battle. In WWII, it accounted for only 2% of the Navy, yet it was responsible for sinking over 50% of the Japanese navy ships. The submarine force now encompasses several classes of nuclear-powered Fast Attack and Ballistic Missile submarines.

DID YOU KNOW...?

• Submarines do not have windows. The only view to the outside is through a periscope, and submarines need to be relatively close to the surface for these to be effective.
  
  
• Submarines are painted black for camouflage. The color works best in the dark, deep of the ocean.
  
  
• To escape from a sinking submarine, the men get into a specially designed "trunk", wearing a life preserver that has a hood on it to provide a bubble of air to breathe. The trunk is filled with water, the outside door opens, and the men float to the surface.
  
  
• In order to submerge, submarines let air out of the top of very large ballast tanks, and let water in the bottom. To surface, air is blown into the tanks, replacing the seawater. The submarine's "wings" are also used to help ascend to the surface.
  
  
• There are two principal varieties of submarines: "Fast Attack" submarines which are smaller and faster and seek out and attack enemy vessels, and fleet ballistic missile submarines, which are designed to carry large, powerful Trident missiles.