The first modern submarine was powered in 1800 by John Holland. Current design follows this initial invention with empty tanks around them to enable them to submerge. When these empty tanks are flooded with sea water by the captain, they make the ship to sink. In order to bring the ship to the surface, compressed air is used to force the water out of the tank making the vessel rise to the surface. The initial design (such as utilized in the World War I) were powered using diesel fuel which need oxygen for combustion. To increase the speed of the vessel, it had to travel over water and once submerged, it utilized battery power to turn propellers.
Due to the limited power of batteries, the submarine would stay under water for a relatively short time. The ability to be unseen made the ship unstoppable and could sink any ship. It was this power that almost made the ships to win the war by themselves. One shortcoming associated with early submarines was the poor living conditions of the sailors on board who woke up with oil heads. Torpedo’s were well known for sinking large ships such as the Lusitania in 1915. It was such action that angered and fueled the war.