Submarine WarfareIt took World War I to prove the value of submarines. Before that, submarines had only a small role in the plans of fleet commanders, mainly serving only as coastal defense units. For the most part, fleet commanders ridiculed the idea that the submarine had any place in naval strategy and tactics. They believed the submarine was just a game. It diverted time and money from other more useful and reliable branches of the service. This view suddenly changed when, on 17 September 1914, the German submarine force demonstrated the importance of submarine warfare. That day, the German submarine U-9 spotted a cloud of smoke and piercing trees on the horizon. As they approached, Otto Weddigen, commander of the U-9, could distinguish three cruisers sailing side by side at a speed of about 10 knots. Each was separated from the others by two miles. Weddigen gave the order to dive. At 6.20am he ordered the first torpedo to be launched. It hit the cruiser HMS ABOUKIR, which began to list heavily. Within 25 minutes it capsized and sank. ABOUKIR was cruising with her sisters HMS CRESSY and HMS HOUGE. When the ABOUKIR was ripped apart by an explosion and sank, the commanding officers of the CRESSY and HOUGE assumed that it had struck a mine. They approached and began rescue operations. HMS HOUGE was next to leave. Two torpedoes hit her hull, sinking her in less than 10 minutes. One look at the U-9's periscope suddenly made CRESSY's captain realize what had happened. CRESSY tried to escape. It was too late. At 7:17 Widdigen launched two more torpedoes. CRESSY rolled onto the ends of the beam. Fifteen minutes later she joined her sisters at the bottom. The news that the German submarine U-9 had attacked and sunk three British armored cruisers in the North Sea made the whole world sit up and take notice. Submarines immediately received closer consideration. Germany entered World War I with only 28 submarines.