U-boats played an extremely significant role in World War I and were the primary reason the Americans entered the war. German U-boats were a more advanced form of submarine. The U-boats allowed Germany to gain ground, but ultimately caused its fall. The u-boat became the primary weapon because it could easily spot its enemies and fire, but remained undetected. This powerful weapon led Germany to numerous naval victories that would otherwise have been impossible because the British navy was the strongest in the world. On 4 February 1915 the Germans declared unrestricted submarine warfare around the British Isles. Therefore, any ship was vulnerable to U-boat attack. Merchant ships were now the main targets. By attacking merchants, the Germans were able to cut off much of the supplies imported into Britain. Additionally, some passenger ships were hit, including one carrying Americans. President Woodrow Wilson found this unacceptable and asked the Germans to stop the war without restrictions. At first they agreed, but soon they continued the campaign and the Americans were forced to join the war. The Americans helped aid the depleting British supplies and fight Germany. Not only did this cause the Americans to enter the war, but Mexico was called upon for help by Germany (because their army was not strong enough to even take on America). In exchange Germany offered to help recover New Mexico and Texas. Because of this, the war became much larger than expected and rightly earned the name World War I. Although the Germans lost the war, they were almost successful with their submarine campaign and destroyed 11 million tons of shipping. Because of this success, submarine warfare was reintroduced to the world after previously thought to be...half of paper...lightly built merchant ships in one fell swoop. This weapon made the U-boat an even more intimidating adversary, with an unexpected deadly attack at any moment. Works Cited “United States Ultimatum to Germany Concerning Unrestricted U-Boat Warfare, April 18, 1916.” 2009. First World War. March 18, 2014, 6:14 am http://www.firstworldwar.com/source /uboat1916_usultimatum.html“Submarine warfare in World War I” Cityofart.Net. March 21, 2014, 10:23 am. http://www.cityofart.net/bship/u_boat.html“U-boat warfare in World War I.” Lowrey, Michael, Dufeil, Yves, Johan, Ryheul and Helgason, Guðmundur. Uboat.Net. March 17, 7:24 am. http://www.uboat.net/history/wwi/index.html“Germans unleash U-boats.” 2014. The History Channel website. March 18, 2014, 6:07am. http://www.history.com/this-day-in-history/germans-unleash-u-boats. Dooly, William G. Great Weapons of World War I. New York: Bonanza Books. Press.