'AB' (ii) was the designation of Allied slow convoys (together with a numerical and sometimes a literal suffix) plying the route across the Indian Ocean from Aden to Bombay, India (September 1942/October 1944).
The first of these convoys was AB.1 of 29 September/6 October 1942 with the unescorted 7,754-ton British Santhia, and the last was AB.45A of 8/19 October 1944 with the unescorted British dredger St David and the hopper barges 101 and 102.