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I've read somewhere that one dTon was equal to two 5' x 5' squares on a deckplan. Is that true?

In that case, the space represented by those two square is 10' high. I guess that's not a big problem for a fuel tank or engineering space. But do the staterooms have such an headroom? Or is there some space between the ceiling of one deck and the floor of the deck just above it?

If there is such a space what rests inside it?
in CT one dton is 1.5m by 3.0m by 3.0m tall. yes, the overhead is ten feet or so above the deck.

CT canon says that the four dtons of space alloted to each cabin includes lifesupport equipment. this would probably occupy the overhead of most staterooms.
Also if I understood correctly the 3.0m would be the distance between the decks/floors.
Since floors are not 1 mlecule thick you should think of it as this way


the - line is the floor of a deck
the x line is the things found under the deck
the s represent the space between the ceiling & deck
the = line is the ceiling of the next deck or the outside of the ship
so between the 2 ----- lines the space is 3.0m apart

That is why when you walk into a cargo bay that is several decks high it seems BIG

When I do a deck plan I usualy figure that the actual head room is 7' with the other 3' as equipment space. Recently I have been putting all of this space above the living (?) space but there is no reason not to have 1.5' above and below. Other than then you can't have ducts for people to crawl through
I usually plan on 2 m doorways and 2.5 m ceilings. Bulkheads and Hulls are .2 m thick.
non airtight walls are .1 thick That means a standard one square corridor is usually between 1.3 and 1.4 wide.
One stateroom module is 4 dTon. If you consider a 10' deck-to-deck height, and a 7 to 8' headroom, you've got 2 to 3' between the ceiling and the floor of the deck above.

If you multiply those by the floor surface of one stateroom, that is 200 sf if I'm not wrong, you've got between 400 and 600'. One full dTon per stateroom.

All devoted to life support? Then I guess TU life support is just as cumbersome as TU computers... Even by todays standard.
Yes, but IMTU this "life support" includes air circulation system, water recycle system, food storage, and solid waste reclaimation. Backup battery packs to operate doors and iris valves for 6, 12, or 24 hours, depending on ship, in case main power fails. And the big one, disassemblied furniture.

The ceiling is 2.3m above the deck.
Originally posted by Randy Tyler:
Yes, but IMTU this "life support" includes air circulation system, water recycle system, food storage, and solid waste reclaimation. Backup battery packs to operate doors and iris valves for 6, 12, or 24 hours, depending on ship, in case main power fails. And the big one, disassemblied furniture.

The ceiling is 2.3m above the deck.
All good ones, and if I may add a few more off the top of my head...

Fire suppression systems, holographic display generators, and emergency rescue balls
. But yeah, the configurable furniture that hides away is one of the biggies volume wise.
Don't forget that wiring and data cables also have to go somewhere. Can't have that sort of thing exposed on civilian ships can we.

Incidently IMTU iris valves also have a hand crank which obviously can manually open an iris valve, but it is not fast and watch out for pressure differentials.
Ok, it isn't that empty beneath our feet.

But I'm somewhat sceptical about the configurable furniture stuff. Isn't it a BIG waste of space and mass?
I use 2.5 meter doors, and 3 Meter high Ceilings, with the Actual Decks/Hull thicknesses around 50cm, for Tech Level 13+. Lower Tech ships are bulkier/crappier/crampier...

Currently, there is a design school within the Auto Industry that is trying to make a new type of Car that uses a standardized "Skateboard" that all the other features of the Car (the Body, seats, etc...) are added to. It is an electric or Fuel Cell car, I forget which... anyway, the current prototype is about 11 inches thick, and contains all the things that make a car work as a car. They are shooting for 6 inches thick for the production version.

It's like that with the ships in the games that I am running... Bulkheads and Interior walls are around an inch or two thick, and contain everything necessary... Power, LP, etc... these are made of "Starship Construction Material" which can range from a superhard metallic substance to a plastic-like composite, or even a glass like substance, dependent upon the manufacturing process... that's showbiz with High Technology...
Dave Chase must've been aboard a naval vessel! His explanation is the best so far, but he's kinda got it upside down.

For the most part, you walk on the steel that seperates the decks, or rather, whatever kind of floor covering they put on it, which may be as little as paint or non-skid, or as much as tile, decking, or even shag carpetting. True, there are places where you have things under the deck, but 9 times out of 10, you will have had to step up onto it. This step is usually about the height of a single step, or about 9 inches (~20 cm).

The air conditioning ducts, water pipes (hot water, cold water, and drinkable and non-drinkable vesions of these), steam pipes, fuel pipes (perhaps multiple kinds of fuel, depending on what kinds of subordinate craft you carry), oil lines, telephone lines, network lines, bracing for each frame (a frame is a section of the ship which is typically about 10-20 feet along its length, but there is no hard and fast rule), firemain(s), and if the crew is industrious, there may be lines for their own personal networks so they can play Unreal Tournament during Med Cruise.

Obviously, an aviation ship will have more fuel pipes running around and probably more fire suppression lines. Surface combat ships in the nuclear age will have a sprinkler system for washing contamination off the hull. Amphibious and submersible ships will have extra piping for pumping ballast water in and out.

Some of these pipes are 18" or more in diameter!

I would imagine that in the future, pressure-sensing equipment would be cheaper and more sophisticated, and would be incorporated into an iris valve's installation if that valve was in a major bulkhead. Such a gauge would tell you if there was a huge pressure differential or not. Modern warships don't do this because the pressure differential between their "clean" sections and "dirty" sections is not so great, maybe a quarter of an atmosphere. You just need to have a firm grip on the door to keep it from smacking you, if you're in too much of a hurry to follow the proper airlock proceedures.

Most if not all passageways will have a headway clearance of 7 feet, which is more than enough for most people. Ships designed for taller or shorter people will be correspondingly different.

That upper 3 feet or so seems big on paper, but in practice, when you have to get up there and clean it, it can be quite crowded at times and quite open at others. Either way, you need a stepladder to get up there, and if you're sliding yourself over a big vent to get at another one, you may be standing on the top of that shaky 6' monster.
Please note that Engineering spaces tend to be quite different from the rest of the ship. You almost always walk on a tall false deck (so spilled fluids go into the bilge, and don't cause slipping hazards), and they can have any kind of pipe going anywhere. They may have extra-high ceilings (like 14') to accommodate large, bulky equipment like boilers (and I suppose reactors) and can have any kind of pipe going anywhere. Most are huge, too. Often you must climb over or around things, and there's plenty of stuff to bump any part of your body, not just your head.

It is loud down there, too, so earplug usage is usually enforced.
I've spent some time on minehunters, and while there are plenty of pipes, cables, and lines hanging from the ceiling and on the walls, the deck-to-deck height is still 7 to 8'.
Oh, but please make ceilings higher than 7'. That gets very claustrophobic for us folks that happen to be taller than 6'. Most houses (at least the ones I've been in here in the USA), have ceilings at 8'.

If you get a wild hair, you could check out Tom Clancy's SSN (or is it Submarine) which is a documentary book on USA's submarines. That would probably make it the most realistic since subs are the closest thing we have to anything like a Traveller starship.