In my HUMBLE opinion, "realistic" is a sonarman that hears contacts, a navigator that plots them and a weapons officer who sets the torps up for you. I doubt many submarines see the commander running back and forth from the periscope to the hydrophone to the torpedo station to the map table, etc...
More likely, people are doing all these things as he calls out the orders. Im pretty sure its been said before, but after reading a few things on here, I thought id say it again. It just FEELS realistic for me to click the "fire" button on the Weapons officer commands as if im yelling "Los"... and he fires the torps. When I look at the map, I see a contact drawn on there by a sailor taking cues from the sonar contacts...
Much less multitasking for this captain!
Though sometimes I DO like to jump on the hydrophone and listen. I just wish there were key commands for telling weapons officer how I want my toprs set... That would be nice.