I find that against a skilled opponent, most subs come home damaged before they are empty. the forward sub base theory works well if an ARD is available. otherwise I look for a level 7 port closest to the patrol zone. That can take care of 5 points major damage, which is quite likely.
The key in sub opps is to have a strategy, keep records, and adjust as success varies
i generally remember (say, 2 out of 3 turns) to look at the Ships display (hotkey S) at the beginning of my Orders phase. I sort the list for highest flotation damage, & examine any TF that shows bad hurt. they get set to Cruise, patrol-zone canceled, and sent to disband in a base whose facilities are equal to the needed repairs (some might be better off going to an intermediate base to repair sys damage, before moving on).
another useful thing, look at the Task Force screen (hotkey T), filter for Sub Ops, & sort by Torp. any SS w/ 33% or less torps is best sent back to base for refuel/rearm.
3rd, grab every upgrade you can. subs can upgrade at any (supplied) friendly port, shipyards aren't needed. ya can't do anything about the torp-abilities but wait 'til 9/43, meanwhile they need the radar, the AA, & something a bit more fearsome than a 3" deck gun!
< Message edited by jmalter -- 4/10/2013 5:33:18 PM >