'GU' was the designation of Allied military ocean convoys (together with a numerical and sometimes a literal suffix) plying the route from North-West Africa to the USA (November 1942/June 1945).
These convoys were started after the implementation of 'Torch', and were divided into 'GUF' fast and 'GUS' slow convoys. The 'GUF' convoys plied the route from Oran, Algeria (later Naples, Italy) to Chesapeake Bay on the east coast of the USA. The first of these 25 convoys was GUF.1 which departed Casablanca on 29 November 1942 with five US merchant vessels in the form of the 7,864-ton Elizabeth C. Stanton, 10,221-ton Kennebec, 6,509-ton Thurston, 8,428-ton Charles Carroll and 10,210-ton Thomas Jefferson. The last was GUF.22 of 16/28 April 1945 with four US merchant vessels in the form of the 6,214-ton Archer, 12,600-ton Delta, 6,507-ton Santa Maria and 6,963-ton Tarazed, escorted by four US warships in the form of the Cowie, McLanahan, Mervine and Ordronaux.
The 'GUS' convoys plied the route from Port Said, Egypt or Oran, Algeria (later Naples, Italy) to Chesapeake Bay on the east coast of the USA. The first of these 98 convoys was GUS.2 of 22 December 1942/13 January 1943 with 44 merchant vessels and no escorts, and the last was GUS.92 of 27 May/11 June 1945 with 34 merchant vessels and no escorts.