IIRC, a LCDR who commanded a boat was referred to as Commander, even as an O-4 rather than an O-5. I could be wrong there.
He had no braid on his visor, so LCDR unless he was promoted after that picture was taken above.
umm, incorrect, the officer in charge of a ship is referred to as Captain regardless of rank. I had just misremembered reading his/Harder’s remarkable exploits decades ago.
Also, though I didn’t recall many/most US Pacific subs with a full CDR as Captain his citations answers my ques