Flying Ducthman- looking at the careerstart.upc you should be able to start a career in the far east command with a s boat and the as the bases are lost you would eventually wind up in fremantle.
also you can edit the careerstart.upc to include a s boat even in the later years of the war. just look through the cfg file to the midwar start- then the
CareerStart 3.Flotilla 2 which is based in fremantle and add a s boat to the start up list like this F2Sboat, 6
this will start you in the midwar setting, but if you want to start the war in 1941 you will need to start in manilla and go from there.
it is possible to change your starting point to fremantle with a s boat, but you would need to edit the flotilla.upc file by replacing manilla with the settings from fremantle. that would do the trick for yo since that has the correct map coord and everything else.
about looking at the harbor and if ships are there, I haven't found a file or map with that data but I will keep my eyes open for that.
good luck all