Many thanks to all. I enjoy being able to have some measure of immersive experience (submersive, in this sim

) and so it's fun to know what some of the equipment is supposed to be for, even if there's no interaction with them.
In the case of the fuse rack, I actually have a similar arrangement in my Chrysler minivan for power distribution. I've got 6 two-way radios, chargers for a couple of handheld radios, and a scanner mounted, with separate fused power terminals for each. There's a 60-amp fuse mounted 4 inches from the battery terminal in case of a catastrophic short to the cable between the fuse panel and the battery. Yes, the van looks like a porcupine, and yes, my smarter half disapproves..... <sigh>
Makes me wonder if there's some sort of main breaker on the buss from the fuse panels to the battery banks in the subs. I learned early in my radio career how much smoke they put into the "big red" wires at the factory. Presumably one of the first switches or breakers that sub non-quals learn on the boat is where that one is, but it's just a guess, as I've never been aboard a sub that was still in service.
Again, many thanks for all the help. What a great community we've got here.
-- Zygoma --