sorry help needed again

[The Chef]

Hi,

i am currently trying to convert the reimagined Battlestar Galactica to the rules presented in High Guard. However, the only sizes of the galatica that i can find are presented in the battlestar wiki. These are:

L: 1438.64m
W: 536.84m
H: 183.32m

Now based on these figures the dton range of the Battlestar Galactica will be approximate 10million dtons. can this be right as i would have thought it would have been a lot lot smaller than this? (10million seems afully big as highguard stops at 1million and i consider that huge, but then again i do have a difficulty in visualising ship sizes as presented in traveller)

has anyone else converted the bucket to Traveller? or does anyone have some definative facts on the correct sizes

any help greatfully recieved

Chef

 

[GypsyComet]

As SF starships go, Traveller's megaton top end is not all that impressive.

Those bounding dimension on the Galactica don't take into account that there is a lot of empty space in that bounding box. Only the engines and the very top of the forward hull come close to the full depth, and only the launch wings reach the maximum width. In the original, the launch wings could just see each other under the hull, IIRC. Lots of empty space.

 

[Madarin Dude]

By my calculations you are right it if is a square ship. Considering the design about half that would be the actual volume. It is over a kilometer long so no wonder.

 

[The Chef]

oh... i've always seen the top end as almost superstar destory size.. but as i said i do have a little difficulty in sizing the ships correctly.

 

[GypsyComet]

i've always seen the top end as almost super star destroyer size...

The SSD (and regular Star Destroyers for that matter), the Exelion, the Nemesis, LEXX, Red Dwarf... Lots of BIG ships in SF. Even the "normal" capital ships of Star Wars are monsters.

A million ton sphere is only 150 meters radius. Around 1,000 feet across. Two city blocks. Tiny.

 

[saundby]

There's a T20 envisioning of the BSG on another board here:

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=15440

and

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=15399

It should be an easy conversion. Post it once you've got a design. Sometimes there're other uses for great honking space colonies with drives for those of us not playing a BSG campaign.

 

[The Chef]

ooh thanks very much. i'll let it give me a headache for a few days then i'll post what i have.

Thanks again

Chef

 

[Lorcan Nagle]

oh... i've always seen the top end as almost superstar destory size.. but as i said i do have a little difficulty in sizing the ships correctly.

they can get much, MUCH bigger than an SSD...

 

[Stofsk]

This reference picture may assist you:

Someone on this board recently said that a modern-day CVN would be approximately 20,000dtons.

I don't know if a Battlestar would hit 10 million dtons, but they're pretty big. What's worse, the Pegasus is at least double Galactica's size. Now there's a big ship! (Stupid Lee had to go and break it didn't he... :roll

 

[cbrunish]

CVN-76 USS Ronald Reagan has approx 88,000 tons displacement and has a length of 1092 ft (332.8 meters). It carries approx 90 helicopters and planes. 8)

 

[BP]

... highguard stops at 1million ..

Now don't let a little thing like rules stop ya! They're made to be broken!

As for monster size ships (other than for Monster Starship Rallies ) - it makes more sense in Traveller setting to just use many more ships (because of the maneuver and spinal mount limits- in combat the biggest ships would have no maneuver advantage and be sitting ducks without a significant enough fire advantage for swarms of combatants).

Bigger isn't always better - even modern carriers and battleships are, I believe, smaller than their older WWII cousins (though they would win in outright battles against each other). Economics of scale.

While jump drive capable systems have no real need for gigantic Colony ships - older or non-Jump cultures would.

And there is always ego - which trumps economics and practicality every time .


Oh - and here are some comparison charts (not done by me) which may help in the visualizing...

and he has more see here.

And even more (even with a ring world) can be found here.

 

[Rikki Tikki Traveller]

Just because the tables in HG stop at 1 MTon doesn't mean you have to. Just extend the tables using the same progression. Drives are % based, so that wouldn't be a problem.

I might even allow more than one spinal mount on those monsters (say 1 per 1MTon?).

 

[GamerDude]

Thanks to BP for those links and Stofsk for the nice views of the BSG. It's nice to see everything relative to each other.

 

[lucasdigital]

Hi,

has anyone else converted the bucket to Traveller? or does anyone have some definative facts on the correct sizes
any help greatfully recieved
Chef

I considered producing the deck plans, until I sourced the same data you've put together. It would be really cool, but about a year's worth of drafting. The world daunting doesn't really do the effort justice.

If you manage to convert the ol girl, give us a peek at the results..

 

[Tobias]

Someone on this board recently said that a modern-day CVN would be approximately 20,000dtons.

Technically, I said it would be less. :wink:
But yeah, it should be in the same ballpark. It's difficult to tell exactly because warships are measured in displacement (of water) and not in total volume.
The largest supertankers today are about 50,000dtons.

 

[Dave Chase]

Thanks to BP for those links and Stofsk for the nice views of the BSG. It's nice to see everything relative to each other.

This is one of my favorite starship comparison sites.


www.merzo.net


Dave Chase

 

[StephenT]

Unfortunately, the Gross Tonnage of a modern-day waterborne ship is calculated using a sliding scale involving logarithms, and my maths isn't up to it.

If you are better at maths than me, the formula is:
Gross tonnage = (0.2 + 0.02 * log(Volume)) * Volume
(Volume is measured in cubic metres)

I can, however, work out that a ship with a displacement tonnage of 30,000 tons - so about one-third the size of a modern CVN, or the same size as a WW1 dreadnought - has a volume of exactly 100,000 m³. In Traveller terms, that's 7,142 dtons.

So yes, a modern ship of 90,000 tons displacement would be about 21,000 dtons in Traveller. The largest ship in the word - a supertanker displacing 565,000 tons and 460 m long - is 125,000 dtons in Traveller terms.

 

[PFVA63]

Hi,

If anyone is interested, here is an updated copy of a figure I had put together awhile ago, plotting published volumetric displacement (converted to dtons) vs hydrostatic displacement (in metric tonnes) for a number of different ocean going military ships.

The yellow dots represent aircraft carriers, while the orange dots represent amphibious ships. The blue squares represent mine countermeasures vessel, and the pink diamonds represent modern surface combatants (like frigates, destroyers, cruisers and fast attack craft), while the the green triangles represent non built designs and/or approximations of real ships. The dark dots represnt submarines, and the purple squares represent an approximation I made orf a couple WWI era battleships.

Finally, the white squares and light gray dots are data that I recently added that comes from the "Freelance Traveller" website.

Very roughly, from the data in this graph you can see that;

- for submarines if you dived hydrostatic displacement in metric tonnes by about 13.5 to 14 you get volume in dtons

- for WWI era battleships if you dived hydrostatic displacement in metric tonnes by about 6 to 7 you get volume in dtons

- for modern surface combatants if you dived hydrostatic displacement in metric tonnes by about 4 you get volume in dtons

- for amphibious ships if you dived hydrostatic displacement in metric tonnes by about 3 you get volume in dtons

- for modern surface combatants if you dived hydrostatic displacement in metric tonnes by about 4 and add 1560 you get volume in dtons

Regards

PF

 

[Tobias]

I can, however, work out that a ship with a displacement tonnage of 30,000 tons - so about one-third the size of a modern CVN, or the same size as a WW1 dreadnought - has a volume of exactly 100,000 m³. In Traveller terms, that's 7,142 dtons.

Displacement of warships is chiefly a measure of mass. Displacement of 10,000 tons loaded = Mass of ~10,000 tons loaded. It's not possible to directly conclude a ship's total volume from its displacement, since, for example, a surfaced submarine submerges a very large part of its volume, while a speedboat submerges only a very small part of it.
The only vessels you can directly translate into Traveller dtons (by a scale of ~14 to 1) are submerged submarines, since they obviously displace their entire volume.

So yes, a modern ship of 90,000 tons displacement would be about 21,000 dtons in Traveller. The largest ship in the word - a supertanker displacing 565,000 tons and 460 m long - is 125,000 dtons in Traveller terms.

Errr.... I don't think so. The Knock Nevis (which is to my knowledge the largest supertanker afloat) has a GT of ~260,000. That yields considerably less than that for the entire range of values for K in the GT formula.
In any case, the better method is to use the old GRT value - which is a more or less exact measurement of a ship's internal volume and neatly corresponds to dtons on a ~5 to 1 basis. (1 RT = 2,83m³. 1 dton= 14m³.) Aforementioned supertanker had 238,000 GRT, so somewhat less than 50,000 dtons. She was later enlargened, but that should not have altered the general ballpark she was in.

By the way, I think you confused tdw (tons dead weight) with displacement - which is rather understandable, admittedly. Tdw is a measurement of a ship's carrying capacity, not of its total weight.