19. The US Coast Guard would not allow ships to sail singly
Coast Guard Rear Admiral Adolphus Andrews commanded the area from Maine to North Carolina. In April, in response to the massive losses and his own shortage of vessels to protect shipping, he restricted movement to daylight hours. He also restricted ships from moving alone, and established convoys which worked up and down the coast. They moved from one protected anchorage to another, paused for the night, and proceeded the following day. The preceding month, March 1942, the Royal Navy transferred several escort vessels to the waters off the United States. They also established a Naval Air Station in Rhode Island, which was transferred later in the year to Trinidad.
American naval officers viewed British protection as humiliating and blamed Roosevelt for having given away the large contingent of destroyers earlier in the war. His supporters argued that the destroyers were obsolete as anti-submarine weapons. By August, increased patrols by the British and American Navies and the US Coast Guard reduced the number of lost ships and inflicted casualties on the U-boats. US and British shipbuilding began to produce more ships than were lost by the end of 1942, and improved sonar and anti-submarine warfare capabilities reduced German effectiveness.
