Submarine Warfare

During WWI, the control of the seas was a vital key to victory.  The two ships of the greatest importance were the dreadnaught, a steel behemoth that made all other ships obsolete, and the submarine, the result of new technology and a ship that can attack while remaining submerged under the water.  The submarine was intended to be used an effective counter against dreadnaught, and was used primarily by the Germans.  Other countries had functional submarines, but did not effectively use them as the Germans did.  The biggest problem was the use of torpedoes.  When fired, the torpedo was a very unreliable weapon.  While it allowed the submarine to stay submerged and still attack, the torpedo couldn't maintain a straight course, swerving away from the target into the ground or even the submarine that it was fired from.  The Germans fixed this problem by building a gyroscope inside the torpedoes, helping the projectile keep straight; this technology would later be stolen by other countries through the inspection of German torpedoes.

Thanks to these, Chancellor Bethmann Hollweg called for unrestricted submarine warfare, a "shoot everything that moves" tactic that allowed for the Germans to sink any ship that comes into their field of view, sans their own.  At this time, America was still rooted in neutrality.  Germany, not wanting to provoke another country into the war against them, issued warnings in American newspaper to come to the war zone on boat, otherwise they might die.  Despite warnings, 128 unfortunate Americans of the 1198 other victims pay any mind when German U-boats sunk the Lusitania, a cruise liner bearing weapons for Britain.  President Wilson reacted to matter by ordering Germans to stop unrestricted submarine warfare, or otherwise incur the wrath of the Americans.  German subs then had to surface, radio the target's passengers to abandon ship, then sink the boat.

During the last stretch of the war, Germany was getting desperate and in need of a new plan.  A plan did come, and it involved an aggressive offense on land, with the use of quick moving storm troopers, coupled with unrestricted submarine warfare to cripple the flow of supplies to the opposing countries.  Germany hesitated on this plan because if they used unrestricted submarine warfare, they would drag America into the war against them.  However, they reasoned that the submarines would prevent any ships from crossing the Pacific, the new plan would win the war effectively, and the Americans were a sod bunch who wouldn't take much to deal with.  Respectively, wrong, wrong, and wrong.  The British employed to use of escorting ships with a small fleet of dreadnaught ships, severely reducing the damage done by submarines.  The plan did work, but it was so ineffectively used by Ludendorff that all of his victories made no lasting impression on the enemies.  The arrival of the Americans served more for morale purposes, but the morale was enough to push the lines all the way to the German border.