Close/Open Structure

[asmodeus]

When dealing with ship designs, we seem to mostly deal with spheres, flattened spheres, cylinders, needles, cones, etc. But Traveller starship design also lists close structures and open/dispersed structures.

I have some idea of what I think these are, but I would like some more knowledgeable people to break it down for me in detail. In what type of ships are they most often seen? What are the advantages and disadvantages?

Anyone have some deckplans or pictures of ships with these configurations?

 

[Malenfant]

I was under the impression that 'close structure' meant 'anything that wasn't a sphere, box, or any other explicitly defined hull type'. I guess something like an Eagle from Space 1999 would be a close structure?

A 'dispersed structure' I think is something like the International Space Station. It's not really practical for spaceships, because the acceleration stresses would probably break the structure apart.

I did think that something like the Cygnus from the Black Hole movie was a 'dispersed structure' because it was all framework and girders, but maybe it should be a Close structure because despite that it's still fairly solid.

 

[Flynn]

I thought both were examples of dispersed, but that enclosed structures of such a gangly structure would be considered a Close structure, while exposed structures with girders and such would be considered Open.

Alas, I've been wrong before,
Flynn

 

[Uncle Bob]

For close structure think of the ships from Babylon 5. Especially the Mimbary Battleships.

Open structure the Discovery from "2001", or Boeing's

 

[Malenfant]

I wouldn't call Discovery an "open structure", that's more like a closed one to me - it may be long and lanky, but it's still all enclosed isn't it? Or are you saying it's open because only the front 'ball' part has habitable portions?

A typical orbital shipyard would be "open" though.

 

[Flynn]

Discovery is open to me, because structural supports are open and accessible. The living areas are enclosed, by necessity, but the hull (i.e. the structure against which the various other elements of a starship reside) is exposed.

My thoughts,
Flynn

 

[Malenfant]

I guess that makes sense... so one definition of an open structure could be a ship that was mostly only accessible by EVA?

 

[PBI]

My group always assumed a dispersed structure was a girder in space with modules attached here and there, which is why it doesn't have to pay any extra displacement for carried craft; the craft are on the 'outside' of the hull with access tunnels to the craft.

 

[aramis]

Close structures are things that can be made streamlined enough for skimming....

I'd say the above pics are close structures.

Enterprise NCC-1701_ are all close structures.

The stardock from STTMP that enterprise sits in is a dispersed structure.

The B5 cruiser with the rotating section, I'd put that right on the border, and call it dispersed.


Minbari vessels (which look like fish) are all flattened spheres or wedges, except the vorlon/minbari/humman hybrid whitestars... those are an airframe wedge biplane, not a CS, because they are streamlined, and capable of landing.

The ship From Crusade is likewise a needle.

The Eagle, from Sp1999 is a close structure, but again, almost crossing the line... not because of the external structure, but because the landing legs are on exterior pods... it fails to cross mostly because
1) it's streamlined enough to enter atmospheres; I'd say a special case of PSL.
2) all the pods are directly connected to the main body.
3) I'd generally call it a PSL box.

The Galactica is also a close structure. Both versions.

The dispersed structure, to me, and based upon illustrations in CT sources, implies not just a framework, but multiple bits of framework, connecting disparate pods. Like the station in the start of ST:TMP (the one V'Ger eats).

The Discovery from 2001 is a needle unstreamlined, not a dispersed structure...

The ship in 2010 is close structure.

Dispersed is not A girder, but several crossed girders.... with pods out on the ends.

Functionally, dispersed structures can't be strealined at all, but close structures can.

All the above IMO.

BTW, it's "close" not "closed", Mal. Some canon designs of other shapes have exposed conduit,etc... look at the pictures of the unstreamlined yachts from TNE.

 

[BetterThanLife]

Sup-9 One of the Cruisers is listed as Dispersed Structure but most are Close Structure. The DIspersed Structure one is basically a large sphere and a small sphere connected by some superstructure and tubes. I would say the big difference is how far apart the parts are and can it be streamlined enough to deal with an atmosphere of a gas giant.

NCC1701, for example, is Dispersed Structure, in all incarnations because all the parts are spread out so much that atmospheric turbulance would rip it apart even though the individual parts are streamlined.

 

[deadlock]

Greetings and salutations,

From Bhoins:
NCC1701, for example, is Dispersed Structure, in all incarnations because all the parts are spread out so much that atmospheric turbulance would rip it apart even though the individual parts are streamlined.

What would you consider the Intrepid-class starship (USS Voyager)? I think it would be considered a closed structure since it was streamlined enough to land on planets (which it did in several episodes). Or would it still be considered a dispersed structure?

 

[BetterThanLife]

As I recall unlike the Enterprise with 4 components connected by narrow strips the Voyager was more one big piece, that would make it Close Structure.

It is (as noted elsewhere in the thread) Close Structure not closed structure. Therefore, IMHO, if it is a bunch of pieces stuck out at odd angles but stuck together, can be generally streamlined then it would qualify as close but if it is a bunch of parts that are seperated by obvious connecting pieces then it is more dispersed structure.

Of course it is all open to Games Operations' Director's, AKA G. O. D.'s, AKA Referee's, interpretation.

Originally posted by Marquis Deadlock:
Greetings and salutations,

</font><blockquote>quote:</font><hr />From Bhoins:
NCC1701, for example, is Dispersed Structure, in all incarnations because all the parts are spread out so much that atmospheric turbulance would rip it apart even though the individual parts are streamlined.

What would you consider the Intrepid-class starship (USS Voyager)? I think it would be considered a closed structure since it was streamlined enough to land on planets (which it did in several episodes). Or would it still be considered a dispersed structure? </font>[/QUOTE]

 

[Antony]

The standard type L Laboratory ship, is according to the Brilliant Lances Technical Booklet, book an open frame while the Donosev class survey ship is a close structure as is the Chrysnathemum class DDE. The Reformation Coalition Aurora class clippers are also listed as Open Frame.

 

[mike wightman]

It may be worth adding to this discussion that T20 allows you to upgrade the streamlining of the hull while retaining the basic design configuration.
Thus you can have fully streamlined cylinders, spheres, and closed structures (or, to put it another way, read the configuration table in T20 again

).
Dispersed structures can't have their streamlining upgraded.

 

[asmodeus]

Hmm... sounds like I am not the only one that is a little unclear.

Sigg Oddra brings up an interesting point regarding T20. Another related point would be the significant armor bonus versus meson fire for despersed structures. I assume that is because when the meson beams converge within the "area" of the structure, it may still be outside of the ship itself due to the many "open" areas in the structure.

 

[BetterThanLife]

Interesting so while CT and MT call it Close Structure T20 says Closed structure?

Originally posted by Sigg Oddra:
It may be worth adding to this discussion that T20 allows you to upgrade the streamlining of the hull while retaining the basic design configuration.
Thus you can have fully streamlined cylinders, spheres, and closed structures (or, to put it another way, read the configuration table in T20 again

).
Dispersed structures can't have their streamlining upgraded.

 

[aramis]

The NCC1701 and 1701A are definitely Close structures, as they are PSL designs... (1701 enters upper atmosphere in several episodes... )

 

[Ran Targas]

^ Concur.

I've always assumed that open structure reflected a vessel designed for operating in a vacuum with components dispersed on a rigid frame and no outer skin. Vessels of this type can not be streamlined in the least.

I assume closed implies a vessel that is shrouded in an outer skin but not necessarily streamlined.

Any craft expected to operate in an atmosphere must be both closed and streamlined.