Starship Scale in Campaigns

[PFVA63]

Hi

Finding a picture of a Destroyer or Frigate of comparable weight/displacement would probably give you a better idea of size.)

Here's a plot that I put together awhile ago showing how the listed internal volume of some real world ocean going ships and designs compare to their "hydrostatic displacement", where "hydrostatic displacement is basically what youfind for modern warships on the internet and reference books, and whih is basically equal to the weight of the ship and everything on it, per archimedes rule.

The plot shows the amphibious ship that I had mentioned earlier, along with similar data for a similar French(?) ship, as orange circles. The red diamonds are real world surface combatants (like destroyers and frigates - and some Coast Guard type vessels). The green triangles aredesign studies from various tehnical papers, etc, and the blue squares are for some mine counter measures vessels that I had a paper on.Finally, the black squaes are for submarines and the purple squares are based on some really rough hand caacs that I did my self for WWI era battleships, just to see how they world compare to more modern vessels.

What you can see here is that:

For submarines - a 1000 metric tonne ship wouldhave an internal volume of about 1000*0.0732 = 73.2 dtons (where 73.2 x 14 cubic meters/dton = 1024.8 cubic meters).

Or looking at it another way,

• A small diesel electric sub like a German Type 209 might be about 131 dtons (in Traveller terms)
• A mine vessel like the European Tri-Partite class might be about 151 dtons
• a Coast guard cutter like the USCG's 270ft class, might be about 450 dtons
• a Frigate like the USN's FFG7 might be about 1025 dtons
• a Destroyer like the USN's DDG 51 might be about 2250 dtons
• while a WWI era battleship like HMS Dreadnought would be about 3160 dtons (or so)

Regards

PF

 

[BardicHeart]

So if you're math is correct then a Nimitz class aircraft carrier would be about 8,052 dT??? o:

 

[navanod]

Here's an article by Ken Pick that goes into comparison with real world ships. Not sure of it's accuracy, but it's the yardstick I tend to use.

http://www.freelancetraveller.com/features/shipyard/tonnage.html

 

[PFVA63]

Hi

I have some very limited data for hree aircraft carriers that show a rough trend of Vol in dtons = 0.258 * (hydro displ) + 1561.6 (I think?). Unfortunately the three points range from about 19,000 tonnes to 63,000 tonnes, so the Nimitz is outside the range of that curve. But if you were to extrapolate, I think you geta size in Traveller terms of about 27,000 to 28,000 dtons (if my info is right). I cn try and add this info to my graph later.

In the mean time, although this is not a CT design, here is a preliminary deck plan for a 2000 dton Armored Warship that I put together using Mongoose's rules, last year. Hopefully it might give you a rough feel for how big a 2000 dton ship in Traveller might be.

Regards

PF

http://members.cox.net/psjn/Prof1.jpg
http://members.cox.net/psjn/Dks1.jpg
http://members.cox.net/psjn/Dks2.jpg
http://members.cox.net/psjn/Dks3.jpg
http://members.cox.net/psjn/Dks4.jpg

 

[BardicHeart]

Thanks for the link, interesting reading. Big seems to keep getting bigger.

At the end of the web page was a foot note that got me wondering. Here's the relevant bit.

Standard Displacement was defined by the Washington Treaty of 1922, a TL5 arms limitation agreement drawn up to prevent a bankrupting naval arms race after the end of the First World War. This treaty defined maximum sizes and weapons for various types of warship, limited each navy to a maximum total tonnage for "capital ships" (the largest combatants), and provided for replacements to be built at the end of a defined service life. The treaty spawned other treaties further limiting navies, but all such treaties were allowed to expire or were withdrawn during the buildup for the Second World War.

How reasonable would it be to assume something similar exists in the 3I regarding the navies of individual member worlds? As I understand it, the 3I is in some ways like a federation, in that individual member worlds still have a great deal of independence so far as governing that world, while the Imperial government handles the interstellar stuff and other "big issues". I'm oversimplyfing for brevity but that's the fundamental gist of it, correct?

If so would not the 3I perhaps have imposed a limit on the size, in dT, of these individual or "private" navies which could be used to explain why an individual world has a "battlecruiser" of 3,000 or 4,000 dT... but the 3I has ships 100 times that in size.

Like I said, my main interest is in just reconciling things and exploring plausible explainations. Same with how trade and economics might work. Generally all I need for a campaign is an explanation that is sufficiently thought out and detailed to seem plausible and thus allow the suspension of disbelief. But complete dissertation on economics isn't necessary as most gamers won't ask questions that in depth.

The "picture" I have emerging so far is one of 3I fleets having some really big ships, but these fleets aren't everywhere and only get deployed for important tasks, otherwise they stay close to where they are based which will be at strategic systems. Most of the time PCs won't interact with them, may not even see them. Their concerns will be more with that 400 dT patrol cruiser or pirate ship in some backwater system where neither the Imp Navy nor the mega-corp tradeships often venture.

Enjoying all the replies though, lots of food for thought.

 

[shadowcat20]

Does the weight figures include density figures for armor? Ships were getting bigger but were having thinner armor after WWII. Also a lot of new ships have Alum hulls rather than belt armor of hardened steel plate.

During the Falklands war a few Brit ships burned to the waterline because their hulls were Alum. Or so I was told at the time.

I guess it all come down to are Traveller Tonnages Dead Weight or Volume Weight?

 

[kbailey]

LITTLE ships fill in the gaps for small loads, overflow fractions of large loads, rapid dispatch of small special orders, outback runs to stations that cannot support large ship runs. There is a place for them.

HOWEVER, in the socialized marketplace of The Imperium, unnaturally modified market forces do not permit the economic employment of small starships for small delivery runs, creating endless trouble with questionable business practices, smuggling, and more. Were these small special order carriers permitted to charge more than a flat CD1000/ton, a huge number of pissant problems would vanish- for economic reasons.

 

[aramis]

My homegrown Elestrial Concordat setting uses much more "modern sized" ships than the OTU; it's a TL10 setting, and they all carry 2J1, Fission PP's with multi-year durations, and the Type T has an additional fusion plant for jump and high speed maneuvers.
400Td Patrol cutter, 12 crew, 12 staterooms
800Td Frigate, 31 crew, 25 troops, 56 staterooms
1200Td Destroyer, 51 crew, 25 troops, 66 staterooms
1600Td Cruiser, 60 crew, 25 troops, 75 staterooms
Any supercargo in personell are carried by hotbunking,

For comparison, the virginia class SSN is 7,900 metric tons displacement of water... 564.3 Traveller Tons Displacement or so... with a compliment of 134 crew... and only about 1/5th to 1/4th is quarters and C&C systems (Bridge, sensors and bunkage...). I understand that they are not hot bunked, but for traveller purposes, they are probably under 1 Td per man... about 1.5 Td per officer, and probably 0.75Td per rating. And has a similar duration deployed.

If one shoots for similar sized crews, traveller ships will be 3-5x the size of wet naval ships.

 

[Orr]

This doesn't jibe with what mere countries can now on Earth.

Are you sure?

The UK, which is ranked sixth in the world on GDP lists compiled by International Monetary Fund, the World Bank, and the CIA, cannot afford to build, let alone arm, man, or supply, a single CVN battle group.

Navies are very expensive and good navies even more expensive than that.

 

[Orr]

Like I said, my main interest is in just reconciling things and exploring plausible explainations.

Rancke already explained this to you and you don't need to invent an arms limitation treaty which only applies inside the Imperium to make things work.

The big warships and big traders stick around big worlds and big trade routes. That leaves everything else wide open for your players in their small ship.

People always complain about their players going places they didn't want them to go and doing things they didn't want them to do. With Traveller you have a built in reason for your players not to go places and do things you don't want them to do.

 

[rancke]

Are you sure?

The UK, which is ranked sixth in the world on GDP lists compiled by International Monetary Fund, the World Bank, and the CIA, cannot afford to build, let alone arm, man, or supply, a single CVN battle group.

Navies are very expensive and good navies even more expensive than that.

I am.

The UK has a population of 62 million and a tech level of... 7? Let's call it 8 to avoid sidetracking the discussion. According to Striker, the UK has a GWP of 496,000 million local credits (ignoring any trade modifiers). A star system like Mora with a population of 10 billion and a tech level of 15 has a GWP of 220,000,000 million local credits (again ignoring trade modifiers). That's roughly 440 times as much as the UK.

Assuming the UK spent 1.6% of its GWP[*] on its star navy (and ignoring the problem of exchange rates), it could afford to maintain a navy worth about MCr80,000. That would maintain, say, 24 5,000T ships like the Sloan.

[*] That's based on the averages from Striker; 3% of GWP in military spending, 60% thereof going to the navy and 40% to the army.​

Assuming that Imperial world mentioned above spent 1.6% of its GWP on its navy, it could afford to maintain a navy worth about MCr35,200,000. That would maintain, say, 97 500,000T ships like the Tigress.

Note that this is maintain, not buy. Build, arm, man, supply, and replace when worn out (But not replace when destroyed; battle damage repairs are extra).

(If we factor in exchange rates, the UK's local credits are only worth 1/10th as much, but since we're talking about local construction, I think that shouldn't come into it.)


Hans

 

[PFVA63]

Hi

Does the weight figures include density figures for armor? Ships were getting bigger but were having thinner armor after WWII. Also a lot of new ships have Alum hulls rather than belt armor of hardened steel plate.

I think part of the reason for the different trend lines in the plot I posted is that the WWI line is for fairly heavy steel hulled ships with small superstructures and relatively thick armor (for their day) whereas the trndline for the MCM & Surface Combatant line includes at least one wooden ship, a couple composite ships, alot of steel hulled/aluminum superstructure ships without much armor (if any) and some stell hulled/steel superstructure ships without much (if any armor).

As such the heavily armored (densely packed) WWI line shows a lower volume per hydrostatic tonne trend than the MCM/surface combatant line for more modern (less densely packed) ships.

Regards

PF

 

[BardicHeart]

Rancke, that's from Striker book 2, correct? I'll just be over here catching up some more. LOL I'll come back to this once I've had a chance to read up on Striker. Interesting numbers though, without having read everything it seems like even a world with the GDP of the UK (which would be a fairly poor world in Trav I'm guessing) could still afford to buy and maintain a small fleet of 100k dT Cruisers with support ships. This is moving more towards some of the detail I was looking for.

Thanks for the heads up. Back after some more reading

 

[McPerth]

I think most of that is a matter of scale.

HG (IMO) is a very good source for Navy characters, and gives you a sight of the Navy they served on. Most ships you can design in HG are not for RP gaming, but for strategically play (as the Islands Campaign in TCS).

That doesn't mean those ships are not there for your RPG campaigns. They are there, patroling systems, making inspections (usually through their ship boats), showing the flag, and usually not messing on small ships and planetary politics or trade.

As it's said in GURPS space, when talking about generic SF roleplaying : "In most cases, however, the navy is the background threat - the intervention so awful no one wants to risk" (GURPS space, 1988 ed, page 17).

Putting those ships against a usual players' starship (scouts, free/far traders, etc...) is like putting a M1 abrams in car wars: "get out of here or die. No argument posible"

If I were to use the larger scale, I'm still scratching my head a bit how to incorporate everything. It makes the smaller ships seem almost useless. Not just in a fight but even for trade... how many 400 dT traders could compete in a universe that may well have 400,000 dT traders. Seems to me the larger ships would simply dominate the market just as you don't see very many 50' cargo ships on the seas (pretty much none), but you see lots of super cargo ships. The larger ships are just more efficient and cost effective, smaller ships get pushed out by operating costs alone, they can't compete. Same for passenger ships... there's a reason there are lots of big commercial jet liners crossing oceans, but small planes tend to be almost exclusively for private use.

Hope to hear more comments, still puzzling this one out for myself. Anyone ever resolved this in their own campaigns?

What should a 20k dton freighter (like the one shown on MT Rebellion book, if you allow me to cite other than CT) trade on a pop 5 planet? Let alone a 400k dton one...

Tramp freighters on the 100-1000 dton range should fill this gap on interstellar trade, letting trade between hi Pop planets for the big brothers.

I see your question here as "how many 4 ton trucks could compete in a world that may well have 400 ton trains?". Large freighters are like trains, joining high value planets (cities in case of trains) and creating trade rutes (railroads). From those high volume starports (train stations and terminals), tramp freighters (trucks) carry trade goods to low trade volume planets (small towns and villages) and returning with those planet's products to be taken by the large freighters.

How reasonable would it be to assume something similar exists in the 3I regarding the navies of individual member worlds? As I understand it, the 3I is in some ways like a federation, in that individual member worlds still have a great deal of independence so far as governing that world, while the Imperial government handles the interstellar stuff and other "big issues". I'm oversimplyfing for brevity but that's the fundamental gist of it, correct?

If so would not the 3I perhaps have imposed a limit on the size, in dT, of these individual or "private" navies which could be used to explain why an individual world has a "battlecruiser" of 3,000 or 4,000 dT... but the 3I has ships 100 times that in size.

For what I've seen in OTU, planetary navies are too a reserve force for Imperial Navy, so I don't think it whould limitate their ships. As planet governments have bonding treaties with the Imperium, they are allowed to have big ships that can help the Navy in emergencies (in FFW there are several planetary BR and CA squadrons that can be quite helpful...).

Other private owned ships are different. When talking about starmercs, I think to remember they have strict limiation (with some rare exceptions). 5000 dton limit, no PA over factor 7, no nukes, no mesons... (sorry, I cannot recall the article now, not even if it was CT or MT)

 

[Orr]

According to Striker...

You can't use Striker or Trillion Credit Squadron, right? Haven't they been decanonized for that purpose?

 

[rancke]

You can't use Striker or Trillion Credit Squadron, right? Haven't they been decanonized for that purpose?

Why not? The really basic comparison is between 62 million and 10 billion (or 15 trillion if we talk about what the entire Imperium can muster). However you figure out Gross Product and tax rates and stuff, 10 billion people can afford to spend somewhere around 160 times as much as 62 million people. The rest is just chrome.

And while Hunter did indeed once tell us that Marc Miller had decanonized Striker and TCS, he (MM) didn't provide us with any new rules on the subject. So we have to fall back on comparisons with real life. Which turns out to be in the same ballpark as Striker when it comes to tax rates. The '10% of original cost for maintenance' figure is more abstract and somewhat iffier, but the shipbuilding rules are still canonical (even the ones that contradict each other ), so if maintenance is strongly correlated with the cost of the ship (a pretty reasonable assumption until a better one comes along), the relative cost of maintaining a 5,000T ship and maintaining a 500,000T ship is still the same (roughly 1:100 )

If someone can suggest (and document) some more realistic ways to calculate naval budgets and maintenance costs, I'd happily abandon Striker and TCS. After all, they're not canonical :devil:. But at the moment, they are the best available rules, so I don't see why I shouldn't use them until something better comes along.


Hans

 

[robject]

You can't use Striker or Trillion Credit Squadron, right? Haven't they been decanonized for that purpose?

Yes and no.

Yes, the results in Striker/TCS change the game's setting in ways GDW didn't want, and FFE doesn't want. So to that extent, populating charted space with ships based on those rules is not canonical.

But as Hans mentions, there's no current replacement -- and not much of an official statement on how many big ships there are out there.

There clearly are big ships. Interstellar war clearly uses very big starships, and the Imperium and the Consulate have at least a couple dozen Big Fleets (note that the chaos of the Barracks Emperors period assumes plenty of Big Fleets). There are clearly big freighters, at least on the oldest and biggest market routes, and probably on the Xboat routes.

But, each referee can cite whatever source he wants. And as always, the referee is free to populate his setting with as many or few big ships as possible.

 

[rancke]

Yes, the results in Striker/TCS change the game's setting in ways GDW didn't want, and FFE doesn't want. So to that extent, populating charted space with ships based on those rules is not canonical.

If the way FFE don't want the universe to work is having lots and lots of naval assets, then I don't see how decanonizing S/TCS helps. As long as you want ships to be cheap enough that a bunch of near-penniless adventurers can have one, planetary governments can have lots and lots of ships. (And ships are already so expensive that they put quite a strain on my willing suspension of disbelief ).

The real problem is having a setting where population densities average somewhere around 1.5 billion people per system, combined with a stardrive that makes the space between systems pretty much go away for practical purposes.

As for having lots and lots of commercial shipping, that's pretty much embedded in the system too. There are a number of features in the trade rules that makes very little sense unless one assumes that free traders work the cracks in the system to survive. Which means you need a system large enough to provide cracks large enough to support free traders.


Hans

 

[snapshotbygdw]

I tend to avoid getting too technical in my games because of the many clashes that can and do occur between editions and rule sets and also because it reduces the time I have to separate my players from enough cash to make their current location safe. Because of this I've always worked on the following fix for jumps in ship scale: if you take a single world with five competing economic/social blocks how big a ship do you need to take control of the whole world? Once you have a single planet how much bigger must your ship be to control a system? Got a single system empire you'll need a bigger ship if you want to control the local cluster, then something bigger still if you fancy keeping order your way throughout the subsector! Fancy an Imperium guess what bigger still! Size starts as tonnage for single ships in a individual country or planets navy and goes up to represent ships that form squads fleets and navies as you expand out wards. Therefore my first 500t "battleship" that's rules the orbit of a single planet becomes the sector prowling 0000kt cruiser of the Imperial navy!

 

[McPerth]

The only way I foresee using those huge ships on a RP campaign is by settling the campaign on one of them, as they are truly self contained environments (sometimes with more inhabitants than some star systems) that can be full of intrigue and adventure.

As references for this kind of adventures, you must only think on any Star Treck series or see Arrival Vengeance (sorry for talking again about MT. I know this thread is about CT).

In both settings (ST and AV) you can see how big ships mostly ignore small tramp freighters that are supposed to be there, unless those are in need of help or messing with nome illegal activities (mostly as real wet navies do in our TL 7-8 earth).