I've found ships that call at Queenstown, as it was then called, en route to North America but also Australia (Liverpool departing ships used Kingstown, now Dun Laoghaire). I don't expect there was a hard and fast rule, but I've found them calling at Gibraltar, Malta, Port Said, Aden then either Bombay or Colombo. Some of these stops would be necessary for refuelling, I think.