The American naval forces had attacked at least three times during the Spanish-American War, and in May 1898 the most major of which being the Bombardment of San Juan. In March 1915 the first officer of the day was appointed to the El Morro Castle. The Odenwald (not to be confused with the German World War II war ship which carried the same name). Was an armed German supply ship, which tried to force its way out of the bay and deliver supplies to the German submarines waiting in the Atlantic Ocean. Teofilo Marxuach had given the order to open fire on the ships, and the shots were coming from the walls of the fort. That made Odenwald return and its supplies were confiscated. The U.S. came on the day war was declared, during the Scuttling of SMS Cormoran off another small American island, Guam, and this was the first actual wartime shot fired. Click Here for more Information.