Following the raids of the U-151 in early June 1918, the East Coast seemed to return to normal, and most hoped that the threat from German U-boats along the shore was over. But a June 29 telegram from Admiral William Sims in England to the Navy Department seemed ominous.

“Second cruiser submarine at sea. At present off west coast of Ireland. Her field of operations not yet known. Cannot reach longitude of Nantucket before July fifteenth. Shall keep department informed.”