Alright, this might sound awful silly to some of the hardcore realism players (and let me state, I play at 90% realism - only having map contacts and external views on).
But my question is this, given the move away from short-range coastal defense submarines like the S-boats to the idea of a true fleet boat culminating in the successful Gato and Balao subs, would it have been FEASIBLE to upgrade the older, larger Narwhal-class boats into more capable fleet boats - specifically, with upgraded engines giving them a max speed of 19-20 knots (as opposed to their almost never actually reached, 17kt top speed) and extending their range significantly?
I know that we DIDN'T do that because the there were only two ships in the class and they were used often for special ops missions, and they represented a time in US sub development when we were truly confused about what subs should be. The Narwhal was developed to be a "submarine cruiser" that sure looked intimidating but was never really great as a sub or a surface ship. It certainly had potential, but by the outbreak of the war, I believe that ship had literally sailed.
But, I really love the boat and wish to use it in a true fleet boat role, and to do so am seeking some sense of historical feasibility (basically an excuse lol) in somewhat boosting some stats of this boat (most notably increasing its truly awful range) as a not wholly unrealistic representation of a fictional "upgraded Narwhal-class V-boat."
Many of you know these boats inside and out better than I. My question is really, if we had wished to go through the effort to upgrade an obsolete boat, could it have been done in a way that would make it comparable in range and speed to the Gatos and Balaos (I know they could do little about the bad handling, slow dives and shallow test depth)?
I'm not looking to make an uber boat. I just want my stylized fictional captain to command a unique fictional boat that at least COULD have feasibly existed given the technological capabilities of the time (mid 1942 campaign).