Medium Ship Universe

[Sir Brad]

the perennial Large Ship Vs.Small Ship topics got me thinking about how things are in My Trav Universe, and I have realized that I run a "Medium Ship Universe".

what do I mean by that? well I do have Big ships just not BIG!! ships, the practical limit of D-Tones is 10,000, it's just that bigger than that and you have difficulty finding the islands of Economic, Tactical and Strategic brake even points. the biggest ships on record top out at 50,000, up to 100,000 is technically possible but no one is willing to drop the coin on that kind of science experiment.

 

[mike wightman]

Which shipbuilding rules do you use?

 

[aramis]

My last TU was a medium ship universe as well. 10KTd was the upper limit And Nothing I designed for the player area was that big - only the alien TL18 intruders.

In the future, my ATU will use a limit of Computer model x1000 for the maximum size; bis models count as the number, not the increase. I didn't do that in the previous incarnation, tho.

My design sequence is a close variant of MGT.

 

[Sir Brad]

Which shipbuilding rules do you use?

Book 2 for PC sized cargo most of the time though I do brow stuff from Book 8, MT MgT and even from outside the franchise when I think appropriate.

 

[mike wightman]

I've bent the LBB2 rules in the past

If a Z drive can get a drive letter of 6 with a 2kt hull then I reasoned why not go to 12kt with a performance of 1, so that became my upper limit.

 

[Whipsnade]

If a Z drive can get a drive letter of 6 with a 2kt hull then I reasoned why not go to 12kt with a performance of 1, so that became my upper limit.

Ooooh... I like that... Consider it stolen!

Do you have any thoughts on using structural strength issues with regards to gee ratings?

 

[HG_B]

Book 2 for PC sized cargo most of the time though I do brow stuff from Book 8, MT MgT and even from outside the franchise when I think appropriate.

In MgT large ships have a better econ chance than MgT small ships. You might want to closely examine HG rules.

 

[HG_B]

My last TU was a medium ship universe as well. 10KTd was the upper limit And Nothing I designed for the player area was that big - only the alien TL18 intruders.

Do you happen to know what the approx. Trav tonnage a Nimitz Class is?

 

[Sir Brad]

In MgT large ships have a better econ chance than MgT small ships. You might want to closely examine HG rules.

Ship Building is mostly HG over 5K.

I miss read the last query I thought they where asking about Trade rules.

 

[HG_B]

Ship Building is mostly HG over 5K.

Yes, I know. Do YOU know that large ships in MGT are more economically viable to due to ship building rules for them?

 

[Sir Brad]

after half a dozen Mgt Books I stopped collecting that edition as no one would play it choosing CT (with some stuff thrown in from MT to fill gaps) for our Trav (and most other Sic-Fi) goodness.

 

[HG_B]

after half a dozen Mgt Books I stopped collecting that edition as no one would play it choosing CT (with some stuff thrown in from MT to fill gaps) for our Trav (and most other Sic-Fi) goodness.

Okay, so you're not versed in that edition. That's all I wanted to know. Might want to check it out for large ships.

 

[rancke]

If I wanted to run a small ship setting, I'd make sure the navies had some really big ships to spend most of their budgets on and then have them keep those big ships concentrated in the core of the realm, far from the small frontier cluster I'd set my game in. I'd then make the local worlds have populations low enough to limit local ship construction to small ships. And that would give me small ships without the problems that a small ship limit and large naval budgets ought to imply. If you only have a few dozen big dreadnaughts, you may well hesitate to send any of them off to the frontier. But if you have multiple hundreds of small dreadnaughts, sending few of them off to the frontier is a lot less unthinkable.


Hans

 

[aramis]

Do you happen to know what the approx. Trav tonnage a Nimitz Class is?

333m long
77m wide
41m tall

1051281 cubic meters bounding box
525640.5 halved for triangular approximation
37545.75 Dtons
18772.875 dtons halving again for curves and about half the height being tower only.

20KTd is a good approximation. But she only withstands about 1G whole ship forces; she cannot support her own mass. (CVAN 65 CEngr, 1977, during dependent cruise)

 

[HG_B]

333m long
77m wide
41m tall

1051281 cubic meters bounding box
525640.5 halved for triangular approximation
37545.75 Dtons
18772.875 dtons halving again for curves and about half the height being tower only.

20KTd is a good approximation. But she only withstands about 1G whole ship forces; she cannot support her own mass. (CVAN 65 CEngr, 1977, during dependent cruise)

Thanks. It is a good real world comparison for players when trying to visualize Trav ship sizes. If she could support own weight, torps wouldn't be as effective under the keel.

 

[aramis]

If I wanted to run a small ship setting, I'd make sure the navies had some really big ships to spend most of their budgets on and then have them keep those big ships concentrated in the core of the realm, far from the small frontier cluster I'd set my game in. I'd then make the local worlds have populations low enough to limit local ship construction to small ships. And that would give me small ships without the problems that a small ship limit and large naval budgets ought to imply. If you only have a few dozen big dreadnaughts, you may well hesitate to send any of them off to the frontier. But if you have multiple hundreds of small dreadnaughts, sending few of them off to the frontier is a lot less unthinkable.


Hans

That wouldn't be a Small Ship Universe. It would be a Big Ship Universe.

If they have ever built big, it's a BSU.

 

[Jame]

(Nuclear Carrier Stats Snipped for clarity)

20KTd is a good approximation. But she only withstands about 1G whole ship forces; she cannot support her own mass. (CVAN 65 CEngr, 1977, during dependent cruise)

I would say this is a good upper limit for small-ship universes and a good median size for medium ship sizes.

Though my definition for "medium ship universe" is ships topping out between 100,000 and 200,000 tons.

 

[PFVA63]

Thanks. It is a good real world comparison for players when trying to visualize Trav ship sizes. If she could support own weight, torps wouldn't be as effective under the keel.

Hi,

Over the years I've put together a couple plots showing the relationship between some real world warships and their enclosed volume.

Here is a fairly recent one that shows how things have changed for ship over time, but it mostly deals with surface combatants like frigates, destroyers, cruisers, and such.

As you can see there has been some variation over time, with these type ships getting bigger in terms of more enclosed volume for a given displacement, or as its shown in the figure, the metric tonnage of a ship per every 14 cubic meters of volume has been declining from a little over 7.0 in the late 19th century to near 3.0 nowadays.

For comparison I looked up some info I had seen somewhere that included a rough estimate of the tonnage of a notional 60,000t air craft carrier from the early/mid 1970s to a rough estimate of its enclosed volume it showed that this 65,300t ship had an enclosed volume of about 250,000 cubic meters. Putting that in Traveller terms would mean that such a medium sized modern carrier would have about 3.8 cubic meters per displacement ton, or that each Traveller dton is equal to a weight of about 3.65mt (eg, 250,000 cubic meters/14 cubic meters per dton = about 17860 Traveller dtons and 65300/17860 is about 3.65mt/dton).

If we were to try and scale that up to the displacement of the Nimitz class carriers of about 90,000 to 100,000 mt, then my guess would be that they would have an enclosed volume of about 24,700 to 27,400 Traveller dtons.

 

[rancke]

That wouldn't be a Small Ship Universe. It would be a Big Ship Universe.

I know. It would be a Small Ship Setting in a Big Ship Universe and it would lack the problems that Small Ship Universes with Big Population Budgets would have.


Hans

 

[aramis]

I know. It would be a Small Ship Setting in a Big Ship Universe and it would lack the problems that Small Ship Universes with Big Population Budgets would have.


Hans

Not particularly - resource bases being what they are, big ships would be built anywhere there's a large population base of TL9+.

The way to mandate a small ship universe is to change 3 core assumptions:

1. ratio of per-capita domestic product to ship costs
2. ratio of drop-off of demand for time in transit of orders
3. ratio of drive-essential component materials to population bases.

A couple "don't think too hard about it" methods include

A. to require a specific size computer installation to control a specific sized hull in jump
B. To require gravitic maneuver drives and jump drives to have some single-cast part that materials tech limits the size of (Like the Necklin Rods and the Mirror in the Vorkosiverse).