Given a few specific assumptions:
Inertial dampeners
Artificial Gravity
I would go with the BSG style of ships.
No, seriously.
think about it.
Fed style, to get a ship with 5,000 people aboard, you're talking a frickin huge saucer and engineering hull...
Klingon style, well, just enlarge that neghvar design.
Klingon Engineers: Masters of the rescaling the same design.
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Romulan style: well, you got those warbird, which are huge anyway... so meh.
Haven't heard crew numbers for card ships.
But anyway, generally, a single 2 metres by 3 metre room, where the door is in the middle of the long wall, would give barracks style room for up to 8 people...
my room is 2m x 3m, but due to the door being on the end of the long wall, and a radiator just over a metre long middle opposite below a window, and a huge shelving unit, my door is one of those split folding doors, 2 panels (had a plastic crap job, broke the next day when kids fell through it. Yeh, and it was more xpensive than the current one which has lasted undamaged... almost 2 years.
Anyway, with the 2x3 thing... a bed fits wall to wall (trust me) on the short walls...so 2 pairs... that 2 peple. Make them bunks (me and my bro had this room when we were kids, in bunks, so I do know what i'm talking about in the realm of possibility.) thats 4.
Make them triple bunks, which is entirely possible, given just over 2m of vertical space. the lower bed just off the floor, mid bed just high enough to give roll-into room (think the space the defiant's tiny quarters provide) then again for the top, which at that point is at head height, if you're on the 6-foot tall end of the scale.
So say that, 6 people a room.
100 of those for 600 people. Say, the enlisted and NCOs.
100 for an additional 200 people (1 twin bunk per room), say, the higher ranking NCO's and the officers.
so 200 provides for 800 people...
Now lets go with the submarine style of that, forgot the word.. hot something.
3 shifts...
so 200 quarters provide for 2400 people. Line each room up in pairs, long wall 'against' corridor,... thats 6m wide or so, from back wall of one to back wall of the opposite quarters. assuming 2m-wide corridor.
100 rooms, x 3m. 300 metres.
hmm.... Lets put each set on "either side of the ship".
50x3, 150m.
Now lets put it across two decks aswell..
25x3, 75m.
So in that light, a ship can have a habitat section just what, 12 metres wide (4 rooms and 2 corridors wide) 2 decks tall and 75m long. Almost the length of a Defiant.
Considering it's size against a sovvy and so on, you'd be forgiven for thinking that starships are a little on the low side of crew counts...
But considering the area each crewmember usually has, even those who are 4 to a quarters like we saw in some episodes of voyager, and they dont, hot bunk I think the term is...
But then I'm talking proper full-on military style.
As such, a troop transport... lets say the 'habitation' section is pretty square, crossection wise.
so at 3m floor to floor, you stack 2x2, i.e. 2 decks, 2 quarters... 6x tall, and given the corridor, 6x wide.
Lets say this is a huge ship too.... 10 decks tall, and wider for the habitat section that it is tall. so 30m tall... 36m wide lets say.
that is for, 6 corridors, 12 quarters on each deck at each crossection...
so in a single "stack" crosssection.... 120 quarters in a vertical cut of the ship just 3 metres thick (the length of the rooms), 30m tall and 36 m wide.
That alone, given a 3-shift rotation of hotbunking people and each one having 6 beds apiece, 2160 people.
But this is a huge ship too, the habitat section is longer than it is wide. say, 20 quarters in a row... so each corridor is 60m long, with 40 corridors (20 either side), and dont forget, theres 6 corridors per deck in the habitat section.
40x6x10.... or simpler...
40x10: 400, x 6 = 2400 quarters.
2400x 6 people per room, x 3 shifts.
43,200 people.
So each deck is, 20 quarters, corridor, 20 quarters, 20 quarters, corridor, 20 quarters, 20 quarters, corridor, 20 quarters, 20 quarters, corridor, 20 quarters, 20 quarters, corridor, 20 quarters, 20 quarters, corridor, 20 quarters,
240 quarters per deck.
blablabla
A block section , 60m long, 30m high and 36m wide.
Think that amount of internal space can be found somewhere in a fed ship?.
I guess cloning was a big thing within star wars for a reason
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So yeah, say you got this troop transport, where half of its internals is dedicated to the transport and welfare of the troops, but then, this ship is a galaxy class, converted for the specific use,. and its' CROWDED.
How many people owuld be aboard? puts the 'emergency evacuation' numbers on the low side.