In practical terms, the ship/module provides access for a levitating floor (and nothing more).
This is what I had in mind. There's a "levitating floor plate" to stand on that goes up/down through the grav lift shaft. Less of an enclosed "car" ride and more of a platform that just goes up/down.
If it's just a platform that rises/falls through an open (yet enclosed by bulkheads and partitioned by iris valves) space, you've got your Grav Lift.
If you're stacking the Boxes high (to create a sort of "hotel experience") you can have a grav lift platform in every box, but allow only one platform in a vertical shaft to be occupied at any one time (so the others "stack up" to get out of the way).
So, for example, let's say you had 10 Stateroom Boxes stacked vertically on top of each other
(excuses for why remain pending).
Let's say you're on the 10th floor and you want to get down to the 1st floor at ground level ... kind of like any ordinary elevator, right?
So the first thing you do is start in the 10th Stateroom Box, you walk up to the iris valve for the grav lift shaft and you push the wall stud, indicating you want to enter the grav lift shaft.
- Floors 1-9 "lock out" access to the shaft, preventing others from entering until you've left the grav lift shaft.
- The Floor 10 grav platform moves into postion to be stepped on by someone entering the grav lift shaft.
- Floors 1-9 slow to a halt wherever they are located in the shaft.
You enter the grav lift shaft, step onto the #10 grav lift plate (that comes with Stateroom Box #10) and the iris valve to the hallway you entered from closes.
Inside of the shaft, on the wall, there is a touch screen to indicate which floor you want to go to and wall studs beside each iris valve to command that specific iris valve to open.
You use the touch screen to command a descent to Stateroom Box #2 (not #1, the "ground floor").
The grav lift platforms for Stateroom Boxes #1-9 all "collect" into the grav lift shaft of Box #1, occupying the interior of that lift shaft.
The #10 grav lift platform descends to Stateroom Box #2.
You press the wall stud to command one of the lateral iris valves to open and step through, letting the iris valve close behind you.
Grav lift platforms #1-10 move up the shaft, clearing the way for grav lift platform #1 to be positioned in Stateroom Box #2.
When grav lift platform #1 is in position at floor level of Stateroom Box #2 (and #2-10 are now higher in the shaft above), the lateral iris valve reopens and you step back through onto the grav lift platform.
The #1 grav lift platform descends to Stateroom Box #1.
You press the wall stud by the lateral iris valve you want to exit through, the valve opens and you exit the gav lift shaft at your destination.
The only time this kind of "two step shuffle" is necessary is when there are 3+ Boxes stacked vertically and you want to go from the dorsal Box to the Ventral Box (or vice-versa). Any of the intermediate levels can be accessed in a single lift, but in order to get to the end of the line you need to enter/exit/enter/exit so as to let the grav lift platforms "reshuffle" their positions inside the grav lift shaft in order to "get out of the way" of the passenger getting to where they need to go.
The grav lift shaft has enough floor space/headroom space to allow 2 grav lift platforms to be at the floor and ceiling of a single Box's interior simultaneously. This allows 2 platforms to stack on the floor or 2 platforms to stack at the ceiling and still be able to use the grav lift shaft for movement of people (and their luggage).
Which kind of upper and lower doors do you set on this lift column?
The standard is to use vertical axis iris valves between floors, to maintain pressure compartmentalization between decks.
Also, the clamps among several such modules piled up must be also airtight, as otherwise the lift column would not be protected by the sealed environment
Already included in the "external hangar bay" capacity allowance, costing Cr2000 per ton of external docking capacity.
Note that internal hangar bays cost Cr2000 per ton as stipulated in LBB5.80 on p32.
If an internal hangar bay has equipment to assist with the launch and recovery of sub-craft, I figure that "the same thing on the outside of the hull" ought to be adequate for hard docking and securing to other craft as well, hence the additional expense for the capability being built in as part of the stock design specifications.
and sometimes through the top of the hull and sometimes out the bottom of the hull.
Correct.
There are iris valves at the top and bottom of the grav lift shaft, but the grav platform can go a "short distance" beyond the confines of the shaft (I'm thinking 10m or less, usually less). This then gives an exterior access point when the craft is grounded and parked on its landing gear. So rather than needing to drop a set of folding stairs, you can just have a grav lift platform drop down onto the ground/tarmac from the ventral side, step onto it, and be grav lifted up into the interior (assuming sufficient clearance below to do this). Same deal for the dorsal side of the hull ... except there the grav lift platform is likely to stop when level with the outside of the hull so you can just step off onto the upper hull (at which point the grav platform descends and the iris valve closes.
If you're having trouble imaging what this might "look like" in person ... try this
mildly famous example of a grav lift shaft in operation, which opens to the dorsal hull of a craft.
