'OT' (i) was the designation of Allied convoys (together with a numerical and sometimes a literal suffix) plying the route from Curaçao, Netherlands West Indies, to Trinidad, and as such reciprocals of the 'TO' (ii) series (May/July 1942).

There were 14 such 'Outbound to Trinidad' convoys starting with OT.1 of 18/22 May 1942 with the 2,696-ton Norwegian freighter Betancuria, 8,017-ton British tanker Rapana and 7,797-ton Panamanian tanker Sylvan Arrow, and ending with OT.14 of 16/19 July with an unknown number of ships.

Sylvan Arrow was torpedoed and sunk by Kapitänleutnant Adolf Cornelius Piening’s U-155 on 20 May 1942.