A submarine is a watercraft that can move and operate underwater. Types of submarines include civilian exploration and scientific works for depths not suited for divers and military which were extensively used during World War I. The first recorded submarine was constructed in 1620 by Dutch Cornelius Jacobszoon Drebbel under James I of England but was based on the design of its inventor, William Bourne. In 1775, the first military single-crew, a screw-propelled submarine called the Turtle was created by American David Bushnell which was unsuccessfully used to sink a British warship HMS Eagle during the American Revolutionary War. During World War I, diesel-electric propulsion and periscopes were the standard design in military submarines. Countries continuously modified their submarines which greatly influenced the nature and results of the First World War. The British submarine fleets greatly benefited from the development of the periscope and self-propelled torpedoes. On the other hand, German ships successfully utilized depth charges. In addition, the Germans widely used U-boats (from Unterboots ) which were considered to be more of submersibles than submarines since they were mostly above water with regular engines and occasionally submerged when attacking using battery power. These U-boats had a cross-section of triangular shape with a pronounced keel to prevent rolling while surfaced (Historylearningsite.co.uk; Uboats.net). The British submarine technology during World War I was characterized by submarines propelled by steam with boilers and funnels which were designed for quick deployment during battle to serve as mobile minefield against the German fleet. The failures of the K Class led to the construction of the M Class Submarine which used a diesel engine as a source of power. Its guns were incorporated on the deck while its torpedoes were notoriously unreliable. Developments in the torpedoes include oxygen-powered torpedoes which left no tell-tale traces after firing, circling torpedoes for hitting other targets after missing primary and acoustic or magnetic torpedoes which used the enemy’s noise to guide it (Historylearningsite.co.uk). The German submarine warfare during World War I was considered unrestricted. There were six types developed during the war. These were the gasoline-powered U-boats, the Mittel-U, the U-Cruisers, the UB Coastal Torpedo Attack Boats, the UC Coastal Minelayers and the UE Ocean Minelayers. Weapons installed to these boats were torpedoes, deck guns and mines (Uboat.net). The British submarines attained successful campaigns in the Baltic Sea by cutting off iron ore transport towards Germany. In Dardanelles, B Class submarines played psychological support while in the North Sea they played observation and naval blockade of German sea forces (Historylearningsite.co.uk). German submarines on the other hand were noted to attack by groups. U-boats usually patrol and then ambush passing British merchant and military ships. Their strategy is to detect and follow ships on naval routes. They wait until other U-boats have chanced upon their target and then they attack in full force. Due to the speed and power of U-boats, they can run on diesel and charge batteries and then quickly submerge to attack spied enemies. However, this strategy led to the demise of these ships due to the distance to be traveled a