After her extensive conversion from a passenger steamer to a minelayer, "Massachusetts" was renamed USS "Shawmut" (ID 1255) on 7 January 1918 and departed the Navy Yard at Boston on 11 June 1918. She completed her sea trials in Presidents Roads, Massachusetts before steaming to Naval Base 17 at Inverness, Scotland, where she anchored on 30 June 1918. The sea trials had revealed that she and "Aroostook" – the new name for SS "Bunker Hill" – consumed fuel at a higher rate than expected, raising concerns that they would be unable to make a non-stop trans-Atlantic voyage. Cluverius and Commander Roscoe Bulmer devised a plan to refuel both ships while underway with hoses from the destroyer tender . Although this technique was uncommon at the time, and was done during a gale, both ships successfully refueled.