[6][7] During the latter half of the voyage the ships radio operator had heard messages from a British cruiser which judging from the transmission strength had been keeping station with Gulflight.

The patrol vessels were not satisfied with Gulflight's papers and suspected her of refuelling the U-boat, so ordered the tanker to accompany them into port.

While under escort, Gulflight's second officer, Paul Bowers, reported sighting a submarine ahead some 28 minutes before the ship was hit.

Ralph Smith, previously first officer, was now invited to inspect the ship, which was examined by divers and had a large hole in the starboard bow.

The captain had suffered a heart attack and two crew members were reported lost when they jumped overboard after the torpedo hit.

[10] The German government apologized for attacking Gulflight, but refused to change its strategy of unrestricted submarine warfare.

A report by the British admiralty into the attack concluded that the German commander had behaved properly according to "Cruiser rules" defined in international law.

Bryan favoured reconciliation with Germany and avoidance of war, but this policy was becoming increasingly unpopular and was opposed by his subordinate Lansing.

Lansing submitted a memorandum proposing immediate and vigorous protest and coupled with the Cushing incident and the sinking of RMS Lusitania on 7 May, a British ship but carrying American passengers who drowned, president Wilson made a forceful response to Germany.

However, the US economy was already heavily committed to producing military supplies for the British, while American support for one side or the other was likely to prove decisive in choosing the eventual victor.