fuel replenishment

[She-Wolf]

Hello sea-dogs, have a query. I am presently playing 1.4 version of SH4 with no mods (waiting for SH4 Gold to come so I can then use the TMO mod) and my first mission is to pester the enemy merchant shipping around Honshu.

I spent most of the journey down to that area on the surface so over half of my fuel is already gone (game set to realistic fuel use settings). I have sent one merchant to the bottom and have now been told to pick on escorts as well, so would like to meander around for a bit and use up my remaining torps if I strike lucky, but am concerned that I might not be able to get back to PH or Midway to take on more fuel if I spend too much time hunting and would then have to abort the whole mission. In SH3, once you have got rid of your torpedoes you can instantly teleport back to base if you are too low on fuel to get back in real time. Is it the same in SH4 - or (better) is there a base I can go to within reasonable distance please?