Why cannot I refuel

[Von Tonner]

Patrolling the South China Sea we lose our base in Surabaya and are moved to Freemantle as part of the Asiatic Fleet. The first time I played this particular career when this happened I just squeeked into Freemantle on the smell of an oil rag! This time, already having used more fuel than I would have liked I knew I would not make Freemantle. So I plot a course for Darwin, coming through the Sulu Sea, Celebes Sea and Banda Sea. I run out of diesel about 50 miles off Darwin and run in submerged and surface right in the harbour. But I cannot for the life of me figure out how to refuel so I can continue down to Freemantle to refit and reload.

If the game does not allow for refuelling at Darwin, then I do not see any point in playing the "realistic fuel" option which makes this game then more arcade in nature which will be a pity. Am I perhaps missing something? There was no little anchor in the right top corner to click on.