Definition of meaning / use of "One M.C." and the like
 

Anyone?

I'm confuddled...seems to be a permanent state atm.

I assume you mean on a submarine.

Well the One M.C is a speaker system for the control room, maybe it means which circuit to connect the sound to?

I think it goes from 1MC to 4MC...1MC is the whole boat, and the others are various compartmental areas. So a 2MC might be able to transmit from Conn to Engine room, or Torpedo room to Engine Room. Although I'm not 100% sure on that...I'll look it up.

The MCs are also known as 'Kashtans' on Russkie boats due to the 'walnut' shape of them IIRC.

EDIT: Correction, I've just seen a reference to 27MC (Sonar Room) so I'm guessing it's a department/compartment reference.

EDIT:EDIT: More material here and here

To the best of my knowledge, the "MC" stands for "Mass Communication".
The 1MC is considered the "root" because it uses every single speaker hooked up to the MC bus.

After that, I don't know how it breaks down. I was never ship's company -- didn't even *look* at a Blue Jacket's manual.:rotfl:
I do know that the total number of subsystems depends on the size and complexity of the boat. Aircraft carriers probably have about 100, subs probably have 20.