When war broke out the Germans had 29 U-boats. For the Germans the U-boats were very significant as the German U-boats became within 6 weeks of winning the war for the Germans. For a long time the Germans main strategy of the U-boats was indeed to wage a war of attrition against British warships either by direct attack or by using the surface fleet into a submarine trap. One of the main significances was that the Germans had one piece of technology that was not yet completely to the British. The German U-Boats exposed the fact that most of Britain’s industry was obsolete, and that the prosperity of the country depended heavily on overseas investments. Their new submarines proved to be well designed and thought through. The German U-boat force was now primarily based at in Belgium, giving the submarines better access to the sea lanes around England. By 1915, Germany was attempting to use submarines to maintain a naval blockade of Britain by sinking cargo ships, including many passenger vessels. The Germans made use of their advantage, sending out about 20 U-boats to begin the naval blockade. In January, before the declaration of "unrestricted submarine warfare" 43,550 tones of shipping had been sunk by U-boats. The number of sinking’s then steadily increased, with 168,200 tones going down in August. This is very significant as Britain, an island nation, was heavily dependent on foreign trade and imported resources. Britain came within six week of running out of grain.
Unrestricted submarine warfare was first introduced in World War I in early 1915, when Germany declared the area around the British Isles a war zone, in which all-merchant ships, including those from neutral countries, would be attacked by the German navy. Unrestricted warfare caused a bitter argument between the leaders. Bethmann Hollweg argued the danger of alienating neutral countries, particularly the Netherlands and America. He was frightened and persuaded to override the use of submarines this caused annoyance to the conservatives. On the 1st February 1917, unrestricted submarine warfare commenced. It was a desperate gamble with only a slender chance of success. As Bethmann Hollweg had predicted, technical advances enabled Britain to win the Battle against the submarines. Unrestricted submarine warfare, 600,000 tons of Allied vessels could be sunk per month, bringing Britain to starvation within six months
The Germans biggest mistake was to sink the American Cruise-liner, the Lusitania, which was one reason why the USA decided to enter the war in 1917. Without the enrolment of America, Germany may have won the war. On May 7, 1915, a British Cunard Line Steamship, the Lusitania, was sunk off the Coast of Old Head of Kinsale near the South Eastern point of Ireland, killing more than 1,100 people In the United States people responded with a high intensity of resentment toward the German nation. . There were 197 Americans on board when the U-20 sank the Lusitania. The loss of 127 lives was reason enough for a little bitterness. President Wilson objected to the German government. This is of great significance as the attack on the Lusitania was caused so much anger from Americans that they were now willing to join the war. The Americans joining the allies side was a massive blow to Germany as with America on side they had the advantage. America was able to provide support for the allied countries including plenty of soldiers and the design of a new super boat.
At the beginning of the war, the Allies decided to blockade Germany. The blockade of German ports had a huge impact on Germany itself. Food prices rose sharply and food shortages were common. The role of the submarines in this blockade was crucial. The British navy hindered the German fleet from leaving the port while high seas any vessel making for Germany was intercepted and searched. The blockade had great significance as the blockade eventually won the war for the British. During the blockade, 300,000 German people died through starvation caused by the blockade. Germany had no choice but to surrender the war at this point.
British submarines played a significant role in the Baltic and to winning the war. The most important result of the campaign against merchant shipping was the virtual ending of the transport of iron ore from Sweden to Germany. German soldiers were forced to requisition iron ore in much greater quantities from other European countries under their control such as Russia. As the expanding German war machine needed more and more iron, so the need to gain it became more and more difficult. As long as this difficulty occurred, the German army could never be at its most functional and efficient. If the German military hierarchy was putting some of its efforts into such a basic issue as the acquisition of iron ore as opposed to other more military-based problems, then the latter had to suffer accordingly. German best chances of winning the war was through their U-boats, without iron to help build more U-boats, it made it a lot harder for Germany to continue such a strong blockade against Britain.
In my opinion, the most significance caused by the submarine was the entering of USA. The U-boats nearly won the Germans the war as they were able to nearly starve Britain of all food supplies however; in the end, it was indirectly the u-boats that lost them the war. The Germans were within weeks of winning the war however because of the sinking of Lusitania, America decided to get in involved on the allies side. This is very significant as if the submarines hadn’t angered the Americas which lead to them deciding to join the war, Germany may have won the war. If Germany had won them, the war the history that we know today may have been completely different.