[KaleunMarco]

Originally Posted by Mios 4Me

Assigned to hourly diving practice off southern Honshu, I've instead gone hunting off Hokkaido, where the cold seems to keep most of the mosquitoes away, and encountered a wealth of targets. Faced with another five day stint of daily CO2 headaches off Tokyo, I went south instead, intent on tanker convoys out of the Makassar Straits and on the route north to Halmahera. Other than expending a great deal of torpedoes at one particular anchorage along the way, though, I didn't encounter a single ship between Japan and Midway via Darwin. There were planes though, oh yes.

Is this a major difference from stock or did I have remarkably bad luck?

incredibly bad luck.
convoy college is a major passage area for all types on convoys.
makassar strait is another major route to/from Dutch East Indies.
as you headed north from Darwin, you would have crossed a couple of routes going to Palau and then Rabaul and then Truk/Eniwetok.
that patrol must have hit snake eyes on all of the convoy spawn percentages.
too bad for you-ooo.