'OT' (iii) was the designation of US convoys (together with a numerical suffix) plying the route from New York to the Caribbean (Aruba or Curaçao in the Netherlands West Indies) and thence via Trinidad to North-West or West Africa, and inaugurated in February 1943 as a means of sending fast tankers to North Africa for the support of the armies involved in 'Torch' and its exploitation (February 1943/June 1944).

There were 19 such 'Outbound from Trinidad' convoys starting with OT.1 of 5/18 February 1943 from Aruba to Dakar, and ending with OT.15 of 16/27 June 1944 from Curaçao to Gibraltar. The OT.1 convoy comprised four US tankers in the form of the 11,355-ton American Sun, 10,172-ton Cherry Valley, 10,169-ton Esso Norfolk and 10,172-ton Esso Washington. The OT.15 convoy comprised 10 US ships in the form of the 10,195-ton Crown Point, Duquesne, 9,887-ton Esso Hartford, 10,317-ton Esso Portland, 10,169-ton Esso Wilmington, 10,296-ton Lyons Creek, 10,195-ton Perryville, 10,195-ton Spotsylvania, 10,317-ton White Horse and 10,172-ton Wood Lake.