Did i teleport or do something wrong?

Coming back from my first ever patrol - 17k tons, not the best but im happy with my first mission - very low on fuel after trying to get to AM54 round the top of UK and heading back to Kiel thru the Channel - made it to 28km short of Heligoland and ran out of fuel - pressed escape thinking i would be able to refuel at Heligo and chose return to base - magically appeared in Kiel (350km away) with a load of medals and and promotions to give out - what happened.

BTW, i have a list of qualifications to choose from, is Radio the one for my Sonar man because i cant see one that says Sonar or Sound?

My next mission is the same patrol grid, which i dont actually mind but does this change - its the 19/9/39

thanks for any help