I always enjoy reading first hand accounts of technical minutia from ex-submariners on this board. There used to be a blog called The Stupid Shall Be Punished that was operated by an ex submariner but he stopped updating it some time ago. The best part was reading the comments from former and active submariners.

Not to sound rude, but that means what exactly? Ultra-Quiet is a machinery line-up, but the machinery used in torpedo loading is always on... hydraulics cannot be shut off because too many critical systems use it. I've been in several 'shoot-outs' with other boats (and believe me, the bragging rights stakes are always high between crews in the same ports...), and we certainly were moving torpedos around in the room during them. Heck, Sonar Division is the primary author of a ship's Ultra-Quiet lineup, so I can say with some small amount of authority that on most ships, torpedo movement and reloads will still be permitted during that line-up... especially in a combat or expected combat situation. It simply doesn't add enough noise (barring a dropped weapon, which is extremely rare) to bother restricting it.

I'm sure you can do that in reality, but in terms of gameplay, if you can rig for ultra-quiet and still load weapons and conduct repairs, what's to stop players from just keeping the ultra-quiet mode on all the time? As we implemented it, it's an additional layer of stealth that comes at a cost, similar to how it is modelled in Silent Hunter.

How about this? If we reload torpedoes during ultra-quiet, it'll take a "realistic" 15 minutes per torpedo and if we switch off the ultra-quiet we'll get the more gamey 4-5 minutes / torpedo.

Or we leave out damage control and the pumps aren't as effective at controlling flooding?

In actual operations, up North, we would rig for ultra quiet for hours on end. This would be dependent on what we were doing of course. As Shadriss stated, its an equipment lineup. Some equipment would be shut down during the rig... Sometimes the CO would modify this on the fly: "Rig for ultra-quiet with the exception of XXX".

That makes sense, but to Julhelm's point, the game needs a trade off that players are impacted by. It sounds to me like making things realistic would mean removing the command entirely and assuming that we're always rigged for ultra quiet during combat, maybe with a call out from the XO at the start of the encounter.