Armored citadels aboard warships have been around since the Crimean War. They barely exist these days, unless you somehow count putting a few unarmored compartments between your unamrmored CIC and the outside as 'armor' that is.
Andrew Moffat-Vallance (of HGS fame) had a website with rules for citadels. His site had an interesting take on the Interstellar Wars and a wholly new Traveller setting that involved a wormhole and one of the Magellenic Clouds.
As for combat experiences aboard OTU vessels, I'd ditch the 'Yeager Drawl' bullsh*t. Yeager himself would be the first to tell you that particular affectation is little more than b.s. put on by fighter jock wannabes. Combat comms rely on clear, precise, and quickly understandable speaking and not bad Jethro Bodine imitations(1). The Right Stuff is good for the most part, but Tom Wolfe has a lot to answer for.
Phone talkers or battle narrators are anyone's call. USN vessels in the Pacific War had no set practice as it was left up to the captain. Some COs used it, some didn't, and others used it only during certain operations. Those that used it cited the need to keep the crew below decks informed. Those that didn't citied the need to keep comm channels clear for battle and damage control reports. It shows up in the movies alot because it looks good and not because it was a normal practice. GMs hould use it for the same reason Hollywood does.
Space combat in the OTU is like all combat. It's wholly Hobbesian(2); i.e. nasty, brutish and short. It also follows that other military dictum; hurry up and wait. Because you can see the fellow whose going to clobber you well before he gets into the range he can clobber you at, OTU ship combat will be very stressful. A weak analogy can be made with Age of Sail ship combat. Vessels then could watch each other for hours before any weapons could be brought to bare.
Much has been written about purposeful decompression in the OTU. While many opinions exist, the majority seem to draw a military/civilian line with regards to the practice. Military and paramilitary vessels will decompress or partially decompress as part of their battle readiness procedures. Merchies and PCs will decompress only rarely. Furthermore, merchies and PC vessels may not have the equipment/design to decompress and recompress readily.
The amount of 'shake, rattle, and roll' IYTU should depend on how inertial compensators work IYTU. IMTU, inertial dampening does not work instantaneously. It just seems that way because the compensators normally get a 'heads up' from the maneuver drive before any thrust vector changes. Unanticipated thrust (i.e. nearby explosions, collisions, etc.) will effect the crew so everyone is usually strapped in.
Also IMTU, unlike the various 'Star Dreck' series, vessels have fuses and circuit breakers so weapon hits do not ALWAYS cause showers of sparks from various panels. Vessels IMTU have seat/shoulder belts too, unlike the usual 'Star Dreck' nonsense.
Seeing as vessels spend relatively little of their trip time in normal space, I'd expect most crews to be standing at least 'Condition III' watches between the port and the jump limit. Engineering and bridge would be fully manned along with half of the weapons.
As always, YMMV.
Have fun,
Bill
1 - I know of two individuals who, while at nuc school prototype, were assigned additional practice on the sound powered phone system because their usual method of speaking proved nearly incomprehensible over that system. One was 'southern', the other was from an 'inner' city.
2 - Just to make things clear, that's the philosopher and not the comic strip tiger, okay?
