Ship tonnage
- Thread starter Tobias
- Start date
The current largest container ships by volume are the Ever Alot, Ever Aria and Ever Atop at 744,181 m^3 (without on-deck containers).
If you are keeping ship sizes at the same volumes as current ships, they will either have reduced cargo capacity due to the volume required for jump fuel, or you will need to increase the size to account for jump fuel. Another consideration with big ships in Traveller is that the crews are much larger than for current merchant ships, especially for the engineering section.
Yes and no. The dton would no longer be technically defined as a unit of volume, but as a unit of mass. Deckplans would be approximately at 2 squares per dton and one square would be ~2.5 cubic meters.
Cargo capacity will remain exactly the same as will fuel capacity, since the definition of tonnage changes across the board. The crew levels: Yeah, that's a thing, but it still is at the current scale.
I was referring to cargo capacity in terms of volume. And the volume of liquid hydrogen fuel is as low as it can go - you can't compress it any further (OK, perhaps by 1-2% if you can get it down to absolute zero).
Ok, I am in the Mass should be the main design factor camp...
With that when I actually sit down to design ships I work from their function, in example the 1st thing I figure for cargo ships is there cargo capacity and work from there to size and performance profile.
Though when I draw ships, mostly for miniatures gaming internally I work from the constraints of the figures to give the perception of the ship portrayed.
Please note this is most for RPG use not Wargame use. As such the rules of design are pretty plastic.
In my ideal world of Mass controlled ship design, I would design using a meter grid.
With that when I actually sit down to design ships I work from their function, in example the 1st thing I figure for cargo ships is there cargo capacity and work from there to size and performance profile.
Though when I draw ships, mostly for miniatures gaming internally I work from the constraints of the figures to give the perception of the ship portrayed.
Please note this is most for RPG use not Wargame use. As such the rules of design are pretty plastic.
In my ideal world of Mass controlled ship design, I would design using a meter grid.
Which is irrelevant to other game systems.
Fuel can also be re-defined as hydrogen compounds (which even makes more sense, liquid hydrogen being nearly impossible to store) which are as commonly found in the usual fuel sources, including gas giant atmospheres. Specifically, water or ammonia.
Volume does matter for cargo capacity, regardless of game systems. Cargo mass matters for wet vessels because if you try to completely fill a cargo hold with steel, you're almost certain to sink; conversely you could completely fill the same hold with grain or wood and be nowhere near the maximum cargo mass you can carry. In the case of spaceships which aren't at risk of sinking, you could completely fill the hold with steel, but it will have an effect on acceleration.
I don't know the densities of metal hydrides, so can't comment on whether they would give any volume savings for the same quantity of hydrogen. Water, liquid ammonia and liquid methane all give a volume saving of around 1/3 compared to liquid hydrogen if I recall previous discussions correctly (I'm sure of water; less sure of methane and ammonia).
My understanding is that about half the volume and area of a 'stateroom' is supposed to be in corridors and shared spaces (at least in CT-TNE), and that the 3m height is not from deck to overhead, but from deck to deck - it includes between deck spaces for pipework, etc. (or if that's exposed, it gives enough height that the crew aren't constantly banging their heads on the pipes).
Besides, post-CT rules allow for more cramped accommodations for crews for those ship-owners who see labour as an expense.
MT says small staterooms can be double-occupied by hot-bunking. Why you'd do that rather than just installing bunks is beyond me.
Star Citizen literally has to do deck plans that ‘work’. Their standard cargo unit (SCU) is a cubic meter- easy to design for, players can move the boxes more easily, all sorts of drama with boxes spilling after damage, pirating is handy, etc. I expect they do their plans with cubic meters in mind.
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I look at design tradeoffs as priority. So maybe small warships have cramped hot bunk racks but more medical, training and/or kitchen facilities.
An aircraft is also not at risk of sinking, but if you fill the hold with steel, it won't take off. This being the more apt comparison for this particular problem.
IRL when talking about cargo capacity or payload you are talking about mass first, volume second. Efficient designs match one to the other, of course, especially when meant for a specific type of cargo.
This is my line of thought. which seems to be really hard for people to wrap their heads around:
Official rules:
Volume = Limited, defining resource for ship design and performance. Dictates deck plan design, which often fails as a result.
Mass = Implied factor that is left extremely vague and generates many problems when you think about it too closely.
My rules:
Mass = Limited, defining resource for ship design and performance. Does not dictate, but merely guide deck plan design, which has a lot more leeway as a result.
Volume = Implied factor left somewhat less vague that generates considerably fewer problems when you think about it too closely.
Official rules:
Volume = Limited, defining resource for ship design and performance. Dictates deck plan design, which often fails as a result.
Mass = Implied factor that is left extremely vague and generates many problems when you think about it too closely.
My rules:
Mass = Limited, defining resource for ship design and performance. Does not dictate, but merely guide deck plan design, which has a lot more leeway as a result.
Volume = Implied factor left somewhat less vague that generates considerably fewer problems when you think about it too closely.
mike wightman
SOC-14 10K
If only Marc. Frank et al had been a little braver including formula in CT.
Each m-drive could have had a thrust rating in newtons and then the ship designed with the mass of the components being the desired measure rather than volume, the final acceleration rating of the ship easily calculated by thrust/mass. You can then convert to g of acceleration - or not.
Each m-drive could have had a thrust rating in newtons and then the ship designed with the mass of the components being the desired measure rather than volume, the final acceleration rating of the ship easily calculated by thrust/mass. You can then convert to g of acceleration - or not.
No. FF&S made both limited, defining resources.
mike wightman
SOC-14 10K
No. like this
To get actual thrust multiply the "Thrust/100" number by 100.
eg A drive thrust 2.000, H drive thrust 16.000. T drive thrust 36.000
a 200t ship with an A drive would have an accelleration of 2000/200=10m/s^2 or 1g
| Drive | A | B | C | D | E | F | G | H | J | K | L | M | N | P | Q | R | S | T | U | V | W | X | Y | Z |
| Mass | 1 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 27 | 29 | 31 | 33 | 35 | 37 | 39 | 41 | 43 | 45 | 47 |
| Cost | 4 | 8 | 12 | 16 | 20 | 24 | 28 | 32 | 36 | 40 | 44 | 48 | 52 | 56 | 60 | 64 | 68 | 72 | 76 | 80 | 84 | 88 | 92 | 96 |
| Thrust/100 | 20 | 40 | 60 | 80 | 100 | 120 | 140 | 160 | 180 | 200 | 220 | 240 | 260 | 280 | 300 | 320 | 340 | 360 | 380 | 400 | 500 | 600 | 800 | 1200 |
eg A drive thrust 2.000, H drive thrust 16.000. T drive thrust 36.000
a 200t ship with an A drive would have an accelleration of 2000/200=10m/s^2 or 1g
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I don't think this to be the case, just people has different views than you and see many problems in your house rules. If you ask for thoughts, you msut assume you'll get many criticisms from people that thinks differently to you.
I agree with many people that the staterooms are too small, at least for commercial passages (military people have to accept quite worst conditions than people who pay for a stateroom). Current world ships are not a valid analogy, as (as you said yourself, BTW) on them you can always go to the deck for fresh air and to ease the claustrophobia. Sea chips cruiser staterooms use to be even smaller, I agree, but you use to spend little time on them, sleeping time asside. On a starship, OTOH, you probably spend quite more time on them, and the rest on the halls, that would aslo be quite smaller in your system.
Another major problem I see is for subcrafts hangars. With Traveller rules, a 10 dt subcraft would need about 210 kl hangar, and if configurations are similar, you can expect to be able use them for several different desings of 10 dt crafts. In your rules, the volume (and so hangar needs) of a 10 dton subcraft may vary depending on its armor (I guess armored ships to be more dense), its mission (I guess a refuelling shuttle will be less dense when empty, but more when full than a passengers one, and many other factors, so the hangars must be configurated for a specific ship, and things like the modular cutter are fully ruled out.
As hinted in the above point, the mass of a ship can vary from empty to full...
This has been discussed many times. Water (to talk about the easiest to calculate) mass is about 1/9 hydrogen and the rest oxygen. So you can hold a ton of hydrogen in 9 kl, being, as you say, more efficient (when volume is the limiting factor) than Lhyd, but not so when the limiting factor is mass (as your rules suggest), as to have a sinlge ton of fuel you'd need 9 tons of mass.
A J2 ship needs 20% of its tonnage as hydrogen fuel to jump. If your limiting factor is mass, and to have a ton of hydrogen you need 9 tons of water, you need to carry 180% of your tonnage as fuel (if dtons are volume, OTOH, carrying the fuel as water would reduce the needs to just under 13% to keep those 20 tons of hydrogen per 100 dtons of ship)...
This aside, how long do you need to extract the hydrogen from it? I frankly have no idea, but I guess jumps would take quite a longer time...
Another problem with your rules, this time metagaming, is that it makes all current ship plans useless, so taking many gaming resources out of the players' and referees' hands...
Your line of thought may be valid, I won't deny it, but would give a very different paradigm than the one most Traveller players and referees are used to.
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