During World War I, Lowestoft was bombarded by the German Navy on 24 April 1916 in conjunction with the Easter Rising. The port was a major naval base during the war, including for armed trawlers such as "Ethel &amp; Millie" and "Nelson" used to combat German U-boat actions in the North Sea such as that of 15 August 1917. In World War II the town was heavily bombed by the Luftwaffe for its engineering industry and role as a naval base. It is sometimes claimed as one of the UK's most heavily bombed towns per head of population. The Royal Naval Patrol Service, formed mainly by trawlermen and fishermen of the Royal Naval Reserve, was mobilised in August 1939. Its central depot "HMS Europa", was also known locally as the "Sparrow's Nest".