Crew Space Too High in Traveller?

[tbeard1999]

Does Traveller require too much space to be allocated to crew on starships (2 tons per crewman; assuming double occupancy)?

Consider -- the USS Nautilus, the first nuclear submarine, displaced the equivalent of ~300 Traveller dtons. It had a crew of 105. Its nuclear compartment alone consumed 65 dtons (a cylinder 33' wide and 38' high), leaving 235 tons for everything else. If each crewman consumed 2 tons of space, the ship would have only 15 tons for everything else. Looks to me like the torpedo room alone consumes about 30 dtons.

And note that a nuclear submarine envisions journeys of several months' duration compared with the 2 weeks turnarous of most Traveller jumps.

I use a nuclear submarine because it's the most analogous wet navy ship to starships IMHO. However, the problem is similar on surface ships. The USS New Jersey, which is about 8000 dtons, has 2000 crewmen. Considering the huge areas allocated to gun turrets, engines and armor, the ship is definitely allocating less than 2 Traveller dtons per crewman.

I've noticed that cruise ships fit 6 people into a stateroom that would consume 6.6 dtons (of course, things like accessways, appointments, etc., should be added to this). The larger staterooms are about 1.4 dtons per person, double occupancy.

So...should the tonnage for crew and passengers be reduced in Traveller starship design sequences?

 

[pendragonman]

Consider -- the USS Nautilus, the first nuclear submarine, displaced the equivalent of ~300 Traveller dtons. It had a crew of 105. Its nuclear compartment alone consumed 65 dtons (a cylinder 33' wide and 38' high), leaving 235 tons for everything else. If each crewman consumed 2 tons of space, the ship would have only 15 tons for everything else. Looks to me like the torpedo room alone consumes about 30 dtons.

And note that a nuclear submarine envisions journeys of several months' duration compared with the 2 weeks turnarous of most Traveller jumps.

I use a nuclear submarine because it's the most analogous wet navy ship to starships IMHO. However, the problem is similar on surface ships. The USS New Jersey, which is about 8000 dtons, has 2000 crewmen. Considering the huge areas allocated to gun turrets, engines and armor, the ship is definitely allocating less than 2 Traveller dtons per crewman.

I've noticed that cruise ships fit 6 people into a stateroom that would consume 6.6 dtons (of course, things like accessways, appointments, etc., should be added to this). The larger staterooms are about 1.4 dtons per person, double occupancy.

So...should the tonnage for crew and passengers be reduced in Traveller starship design sequences?

How did you come up with 300 dtons for Nautilus?

I show the Nautilus to be 4.25m in radius (R) and 97.5m in length (L). This gives ~63000 cubic meters of ship or ~4400 Dtons. (I used pi*R^2*L= Volume, with 14 cubic meters = 1 dton)

 

[far-trader]

How did you come up with 300 dtons for Nautilus?

I show the Nautilus to be 4.25m in radius (R) and 97.5m in length (L). This gives ~63000 cubic meters of ship or ~4400 Dtons. (I used pi*R^2*L= Volume, with 14 cubic meters = 1 dton)

I think your calculator has a sticky button

Given those figures I get ~ 5530m cubed (for 395tons) and of course that's the rough overall dimensions, actual displacement will be less. I'm sure I've seen most subs listed with the actual displacement figure as that's relevant.

EDIT: Grabbing a submerged displacement for the Nautilis of 4092tons and running the numbers for the weight of water (but I think it was fresh water, not salt, and that'd change it a bit) it comes to ~265dtons.

 

[rancke]

Does Traveller require too much space to be allocated to crew on starships (2 tons per crewman; assuming double occupancy)?

[...]

So...should the tonnage for crew and passengers be reduced in Traveller starship design sequences?

No, because they reflect the realities of life among the stars in the 3rd Imperium. Starship crew get more space than 20th Century sailors. This may be because they're spoiled or it may be for entirely practical reasons ("If spacers don't get enough space, they go on killing sprees").

OTOH, triple or quadruple occupancy seems to be a simple solution for any variant TUs.


Hans

 

[pendragonman]

I think your calculator has a sticky button

Given those figures I get ~ 5530m cubed (for 395tons) and of course that's the rough overall dimensions, actual displacement will be less. I'm sure I've seen most subs listed with the actual displacement figure as that's relevant.

DOH! It would help if I cleared out previous calculations...

 

[mike wightman]

I can think of one advantage a nuclear submarine has over a Traveller starship - it can get free oxygen from the water all around, hence simplifyiing life support issues.
Also a Traveller ship includes a lot of stuff that isn't listed as part of the crew fixtures - grav plates and acceleration compensators are the first that spring to mind.

 

[Golan2072]

I can think of one advantage a nuclear submarine has over a Traveller starship - it can get free oxygen from the water all around, hence simplifyiing life support issues.
Also a Traveller ship includes a lot of stuff that isn't listed as part of the crew fixtures - grav plates and acceleration compensators are the first that spring to mind.

In a similar manner, I've always considered the stateroom tonnage to include not only the stateroom itself, but also tonnage for other features which depend directly on the crew size - life support machinery, the galley, the medlab and the ship's locker. The actual stateroom IMTU is only 2 dtons and, of course, could house two people using double occupancy. So it's 1 person per 1 dton.

Also, how extensive are the life support systems of a nuclear submarine in comparison to those of a starship?

 

[tbeard1999]

I think your calculator has a sticky button

EDIT: Grabbing a submerged displacement for the Nautilis of 4092tons and running the numbers for the weight of water (but I think it was fresh water, not salt, and that'd change it a bit) it comes to ~265dtons.

Submerged displacement makes the most sense, as it will fully define the volume of the whole ship (another good reason to use submarines, rather than surface ships).

In any case, whether it's ~265 dtons or ~290 dtons, the point does not change. Nautilus, at least, appears to have allocated far less than the Traveller standard of 2dtons per crewmember.

Los Angeles-class attack subs have a submerged displacement tonnage of 6900 tons, or about 492 dtons, with about 72 tons dedicated to the reactor room. They carry 141 crewmen. Since they are attack subs, I'd imagine that the torpedo rooms would be larger than the Nautilus (can't find deckplans).

So maybe military ships can pack men in a lot tighter than merchant ships. The USS Tarawa, for instance, carries about 1000 crew and about 2000 marines (plus the equipment for a Marine battalion). Its Traveller tonnage would be about 7600 dtons. Clearly, it isn't allocating 2dtons per person.

 

[tbeard1999]

In a similar manner, I've always considered the stateroom tonnage to include not only the stateroom itself, but also tonnage for other features which depend directly on the crew size - life support machinery, the galley, the medlab and the ship's locker. The actual stateroom IMTU is only 2 dtons and, of course, could house two people using double occupancy. So it's 1 person per 1 dton.

Also, how extensive are the life support systems of a nuclear submarine in comparison to those of a starship?

Pretty comparable, I think, since these submarines stay completely submerged for months at a time. The subs would need to carry far more food and consumables than a Traveller starship, which only plans to be "out there" ~2 weeks per jump.

A long time ago, I estimated that a dton of concentrated food (i.e., MREs) would feed about 500 people for one day. More traditional foods would feed half as many (they are packaged less densely). EDIT -- I misremembered. A case of MREs (12 MREs per case) will feed 4-6 people for one day and 500 cases can be packed into a Traveller dton.

To be comfortable, people need several gallons of water a day. Assuming the ship has a day's worth of water and recycles it from then on, a dton of water would provide water for about 1000 people for one day. To be safe, the ship should carry a minimum of 2 gallons per day per person. (A Traveller dton is about 4400 gallons of water, so this isn't that big a deal, volume-wise. It would weigh a *lot* however, so this might make it prohibitive to carry).

So on a 14 day trip, a single person would need about 0.02 dtons of food and water *minimum*. Not much, really, so this can be assumed to be part of the stateroom cost.

 

[Plankowner]

A submarine makes it's own air and water (from seawater). On a starship these things would have to be carried along, that will drive per-person tonnages up.

Also, the Nautilaus and LA class ships are REALLY cramped for personal space.

An Ohio class Ballistic Missile submarine is better on personal space, but still a good order of magnatude less than a cruise ship (I've been on all three types).

1 dton per person is probably right for a military application with twice that for civilians/passengers.

 

[pendragonman]

To be safe, the ship should carry a minimum of 2 gallons per day per person. (A Traveller dton is about 4400 gallons of water, so this isn't that big a deal, volume-wise. It would weigh a *lot* however, so this might make it prohibitive to carry).

So on a 14 day trip, a single person would need about 0.02 dtons of food and water *minimum*. Not much, really, so this can be assumed to be part of the stateroom cost.

Wow. You must come from the Scout Service. The rest of us like to wash more frequently.

The average person uses more than 2 gallons of water per day if said person is living on MREs. You gotta reconstitute that stuff you know. Then there is drinking water.

Without using more than a gallon a piece (~ a helmet full) for washing purposes in the field, my tank crew (4) used more like ten gallons a day, and by the end of those trips to the field we stank. Badly. And we were only truly camping for two to three weeks at a time. The rest of the time we had access to showers.

We also didn't have to eat MREs for 3 meals a day. Only for two. We got some sort of "hot" food for at least one "rotating" meal a day. No rhyme or reason we could discern to the rotation, mind you, so we never new from one day to the next which meal would be "hot".

 

[Supplement Four]

1 dton per person is probably right for a military application with twice that for civilians/passengers.

Is the 2 dtons standard all actual living space? Or, is some of that space taken up by life support equipment, piping, and blah, blah--so that a person actually has less than 2 dtons to romp around in?

 

[tbeard1999]

Wow. You must come from the Scout Service. The rest of us like to wash more frequently.

Survival texts -- the classic "Nuclear War Survival Skills" list -- state that a gallon per day for a fallout shelter occupant is reasonable, though not for washing.

The average person uses more than 2 gallons of water per day if said person is living on MREs. You gotta reconstitute that stuff you know. Then there is drinking water.

Modern MREs are pretty much fully hydrated (I once had one that required about 1/4 cup of water to rehydrate fruit cocktail, but I understand that this has been deleted).

Without using more than a gallon a piece (~ a helmet full) for washing purposes in the field, my tank crew (4) used more like ten gallons a day, and by the end of those trips to the field we stank. Badly. And we were only truly camping for two to three weeks at a time. The rest of the time we had access to showers.

I was thinking of drinking water, not washing water. One site lists shower water usage as 2 gallons per minute. So a five minute shower, plus plenty of drinking/shaving/washing hands water might total 15 gallons per person per day. One dton of water would provide this much water to ~21 people for two weeks, assuming no recycling (again, water is heavy, which might restrict the amount that can be carried far more than cargo bay volume does).

Anyhow, it doesn't look to me like carrying 14 days of food and water per person is a significant issue.

 

[tbeard1999]

Is the 2 dtons standard all actual living space? Or, is some of that space taken up by life support equipment, piping, and blah, blah--so that a person actually has less than 2 dtons to romp around in?

Well, obviously we can rationalize any amount of space by simply assuming that the extra space is used on other stuff -- life support, corridors, etc.

But Traveller canon deckplans have staterooms that are 3m x 4.5m -- 3 dtons -- for one passenger or two crew.

Interestingly, the problem may be in the assumption of 3.1m between decks. Because the square footage of real world staterooms compares favorably with Traveller, if you assume double occupancy.

Anyhow, maybe Traveller should allow double occupancy staterooms for passengers and some kind of minimal berthing for crew and troops (1 ton each? 1.5 tons each?).

 

[Zowy]

Well, for a 4 dTon stateroom.

I make the cabins 2+ dTons, depending on if I have each one with it's own bathroom / fresher ( for High and middle passenger service ) or make the crew share larger commmon ones. Then toss in all the space needed for lounges, hallways and the galley. Allso my airlocks are part of stateroom dTonage due to them being decontamination / shower equiped. I chop 1/2 meter or so out of the 3M tall headspace, for running fittings, life suport, ect. between the decks ( and maybe makeing a few small smuggling compartments :smirk: ) Depending on the type of ship, the cabins may have oversized or bunk beds for double occupancy, in the crew and middle passenger cabins.

All these things added together still makes 4 dTons seem a bit to big, when you take into account how much ships and space travel cost. But like jump drives useing 10% of a ships dTon per Jn for fuel, I have just let it slide and says it's a cultural or 3I, min. ship requirment thing ( Union / safety / ect. ) and let it not bother me to much.

 

[casquilho]

I realize this is pure opinion, but...

1) I would use care in using a military ship designed to be supported by a larger support ship on a regular basis and a civilian space ship designed to remain independent out in space for long periods of time. They do not feel like the same thing to me.

2) I think we should keep in mind that a person who pays for a ride and a person who is a crew member should have different amounts of space. The crew member would have both their "room" as well as their work areas to move around in etc. The passenger would not be allowed outside the "passenger areas" and thus might need more room to feel normal.

3) I know some folks have said a space ship is not a "home" in space. I disagree. I think the amount of space might reflect the fact that for some folks there is not a "home port" they return to on a regular basis or there is not a support ship they meet up with on a regular basis. I agree some of the military ships would be very much like our modern navy in both how crew is treated and how the ship is ran. But some Scouts, Merchants, and others may not ever have a planet based "home" and the ship does become their house as well as ship. In those cases the crew may need additional space.

Now having said this, I am not thinking they need a master bedroom with master bath, walk in closet and work space attached like the Mc-Mansions of today. I am thinking that a single room at 2 tons does not seem unreasonable for the crew as a space version of their complete personal space.

Just my .02

Daniel

 

[Zowy]

How much room do the Cruiseships of today use for pasenger and crew areas? I allso seem to remember alot of the "steward" services are done by low paid workers from the philipines and some of the poorer mediterranean countries and they get stuck with small bunkrooms?

Of course alot of cruiseships port hop and don't need much more for "lifesupport" than food, water, and alcohol.

 

[atpollard]

From Urban Design, Cities require 100 Gallons per day per person for Residential Uses only. Industry and agriculture can use up to 10 times that amount. Recycling will reduce that, but starships might still use a lot of water.

 

[Zowy]

As I think more on the topic of the 4 dTon per stateroom, in CT ship building. I think the size has as much to due with social and psychology factors as physiology ...

Human shipbuilding is heavy influnced by Vilani social factors.....
K'kree psycholgy results in ships that need for 48 dTons per herd member.....
Droyne have lower life support requirments, needing 2 dTons per tyafelm member...
Virushi ( JotTAS # 12 ) while being larger than K'kree have a strong sense of individulaism so only need 8 dTons per stateroom.....

 

[Ishmael]

I always thought crew spaces were also used for other things, such as the torpedo room having racks(bunks) in them, so there would be overlapping uses for each dton.