Outrigger Spacecraft Designs

[robject]

You know you've wanted one. Some of you have designed them. Let's talk about them.

There have been quasi-outrigger designs with drop tanks -- the Gazelle Close Escort from Traders & Gunboats, and the Excalibur Express Packet from the IISS Ship Files.

There have also been more properly outrigger-style ships, including the TNE Regency "Cuspid" gunboat, which fields a PA gun that must have been pulled from a barbette emplacement.

I think of two themes when I think of outriggers. One is "modularity" -- an outrigger could be a flexible design, and you could potentially swap out modules to change its mission. The other is "support", where the outrigger is sometimes a bolt-on to support one specialized mission.

Thoughts? Examples?

 

[Enoki]

I designed a flexible sized merchant ship a long time ago. This design had the engineering spaces and permanent fuel in a pod at one end, and a bridge and crew pod at the other. In between was a telescoping tube that connected the two pods.
With no cargo, the ship was contracted where the two pods were joined together. Modular cargo bays / containers would be fitted-- up to six if I recall--and hooked to the tube with the two pods acting like bookends. If you wanted more range, you fitted a container with fuel instead of cargo as one or more of the bays.
The whole thing looked like a rectangular box with the front being somewhat rounded off.
The maneuver and jump drives were fitted for the maximum size it could attain and could move and jump the ship if it were in smaller configurations. I never really considered whether these smaller configurations would have increased the jump range or maneuver speed but they likely would have.

 

[bookwyrm]

I've wondered about ship designs that have some part sticking out, engine nacelles connected to the ship by pylons or struts. Star Ship Enterprise or some Droyne ship designs for example.

I only just now considered a way to build ships like that using the T20 ship building rules. it would really add variety to the ship designs of different races and cultures. the downside is that the pylons/struts take up some internal space of the ship. not good for smaller ships, more practical for larger ships. might be a cool design for any size, purpose built, ships.

unfortunately, this method doesn't show how to change the size of the Pylon. like if the Bridge was separated from the rest of the ship by a Pylon, but there was still access from the bridge to the rest of the ship through the Pylon.

this might also fix a problem I had concerning forward facing weapons. as in, they can only fire in the direction the ship is facing. just have them be a weapon nacelle.

or cargo nacelles. can only be accessed when in Port. can't be accessed while in Jump, and need vacc-suits when in normal space. good for keeping passengers & cargo separate for security and/or safety reasons.

cool thread!

 

[Magnus von Thornwood]

Kinda...

I have set the R/SV Elephant Island to function, both as a yard and for Jumps by rigging ships in the yard bay, so it does sorta count as outrigging.

But yeah, the outrigger designs are cool.

 

[Spinward Flow]

Some of you have designed them. Let's talk about them.

Indeed ... some of us have designed them.
Convincing people of the "value added" is the next step after designing them.

I think of two themes when I think of outriggers. One is "modularity" -- an outrigger could be a flexible design, and you could potentially swap out modules to change its mission. The other is "support", where the outrigger is sometimes a bolt-on to support one specialized mission.

Thoughts? Examples?

I prefer to use the term ... Tug.
Jump Tug.
Maneuver Tug.

Basically what you do is design a ship (or a boat) with "overpowered" engines for its intended purpose (jump/maneuver) which you can then use to compute an external load capacity at reduced drive performance (easier with LBB5, but can also be done with LBB2 designs). Basically, you intentionally design the ship to be "overloaded" in a way that permits the drive performance to "degrade gracefully" in useful quantity amounts.

Like this ...

Spinward Flex Courier  XF-1626621-030000-00002-0   MCr 109.8752  194 tons
    batt bearing                   1         1                     TL=13.
    batteries                      1         1                    Crew=2.
Passengers=0 (1 possible). Cargo=45. Fuel=50.5. EP=11.64. Agility=6. FPP.
Jump-1, Maneuver-5 with 0.1-41.5 tons external cargo added.
Jump-1, Maneuver-4 with 41.6-97 tons external cargo added.
Jump-0, Maneuver-4 with 97.1-105.8 tons external cargo added.
Jump-0, Maneuver-3 with 105.9-218.2 tons external cargo added.
Jump-0, Maneuver-2 with 218.3-465.6 tons external cargo added.
Jump-0, Maneuver-1 with 465.7-1455 tons external cargo added.

Interplanetary Travel (distance, acceleration, time) (link)

Once you have that Jump Tug/Maneuver Tug performance info for "slung loads" available to you, you can then (as a Player and/or as a Referee) start figuring out clever ways of making use of that external load capacity.

For example ... using the my own Spinward Flex Courier design, it's perfectly possible to design 40 ton passenger modules, which would fit into the 40 ton internal cargo bay if needed for an orbit to surface transfer, which has 10 staterooms (8 high passengers 1 steward plus either 1 medic or 1 middle passenger). Use a pair of such modules and the 194 ton starship is reduced to jump-1/maneuver-4 performance and needs 27.4 tons of fuel per jump-1 (50.5 tons internal fuel tankage limit), so it would be best to make use of the inflatable fuel bladder in the internal cargo bay (recommend 8-10 tons) to allow for the additional fuel needed by the power plant during a 2J1 pair of 1 parsec jumps in order to move the entire assembly 2 parsecs, with the remainder of the internal cargo bay remaining open for other cargo transport (~30 tons worth).

An alternative scenario of having only a single 40 ton external cargo load would mean that a 1 parsec jump would require (194+40=234*0.1=23.4) 23.4 tons of fuel per parsec on an internal fuel tankage of 50.5 tons, so 2 parsecs of jump range would require some additional fuel storage in the cargo bay, courtesy of the internal fuel bladder built into the design.

If using the entire 40 tons of internal fuel bladder capacity, it would even be possible to ferry up to 70 tons of external cargo load (194+70=264*0.1=26.4) 3 parsecs at jump-1 and have (50.5+40=90.5-26.4*3=11.3) 11.3 tons of fuel remaining for power plant operations, which at 11.64 tons per 28 days (standard) would have an endurance of (11.3/11.64*28=27) 27 days ... which offers sufficient endurance margin for 3 jumps of 7-9 days when including routine 16 hour drive maintenance after each jump (although fuel reserves will be low after breakout from the 3rd jump-1).

This kind of flexible external load capacity, through interstellar jumps and through interplanetary maneuvers, is the reason why I call the 194 ton starship I've designed the Spinward Flex Courier ... because that's exactly what it is ... flexible, due to its capacity to operate as both a Jump Tug and as a Maneuver Tug, if the circumstances (and/or business model) call for it.

The logistics of managing the extra displacement external to the starship can get interesting (particularly in a pirate encounter scenario), but the option IS THERE. Other scenarios are of course also possible, such as straight up external cargo loading (I'm thinking Major Cargo Only for this, with Minor and Incidental Cargo requiring internal cargo bay stowage only) ... but that would be a House Rule on the matter, rather than an explicit one written into the Rules As Written (RAW).

The key points I want to make about Tug ships and boats is that Jump Tugs require a jump drive 2+ (which can then operate at reduced performance of 1+) when adding external displacement to hull displacement. Same deal happens with Maneuver Tugs needing a maneuver drive 2+ (so as to operate at 1G+ at reduced performance) when adding external displacement to hull displacement.

Hope that makes sense. :coffeesip:

 

[agorski]

T5 has codified these designs. Any ship can have multiple hulls and/or under-100-ton pods, which can be fixed or detachable. It's easy to design a full Saturn 5 moon rocket stack in T5.

 

[Condottiere]

Sure, as ballast.

The simplest variant is two fifty tonne cutters, one of which you install the jump drive, adequate sized fuel tank, and bridge; the other, whatever floats your boat.

 

[robject]

Sure, as ballast.

The simplest variant is two fifty tonne cutters, one of which you install the jump drive, adequate sized fuel tank, and bridge; the other, whatever floats your boat.

^ (bolding mine). Pun intended.

You've tidily summarized Spinward Flow's post (that's not a bad thing).

And you have also summed up the Cuspid-class Gunboat: it's two smallcraft hulls with a PA gun in between, more or less.

Going by the picture in Regency Sourcebook, the Cuspid is a ten-ton launch, with something like a seven-ton maneuver drive as the outrigger. Between the two rests the Particle Accelerator, essentially a fixed single barbette. Call it 3 tons.

The result is a 20 ton monster.

 

[Fovean]

Going by the picture in Regency Sourcebook, the Cuspid is a ten-ton launch, with something like a seven-ton maneuver drive as the outrigger. Between the two rests the Particle Accelerator, essentially a fixed single barbette. Call it 3 tons.

The result is a 20 ton monster.

For some reason this makes me think of some of those asymmetrical Star Wars ships, like the B-Wing.

 

[robject]

For some reason this makes me think of some of those asymmetrical Star Wars ships, like the B-Wing.

Yes, it has a bit of that feel. The B-Wing looks sleeker than it, though!

 

[Timerover51]

If I read the T5.10 ship construction tables correctly, a streamlined 90 dTon pod costs 5.6 Million Credits, The pod, if carried in space, must be both airtight and well insulated. It will also need to have sufficient cargo hatches to be able to load and unload cargo, preferably at both ends, so as to avoid having to totally unload the pod to get at the item of cargo to be unloaded first. Before you say this is not possible, I have seen it happen with cargo trucks, where the first pallet to be unloaded is the first pallet put on the truck, meaning that all of the other pallets have to be moved to get at that one

Now, this cargo pod is not weightless, but is the equivalent of a 450 gross register ton submarine hull. Say it weighs about 200 or so metric tons. Does it also have some form of landing gear or feet so as to prevent it from sinking into the ground, or is it only dropped off on a hard loading-bearing surface like a runway? How much cargo are you planning to put into this? You return on investment per fully loaded pod is 90,000 Credits per loaded trip. The numbers do not seem to add up real well.

 

[McPerth]

I'm not sure to understand the concept or outrigger spacecraft...

 

[robject]

re not understanding the concept of "outrigger" spacecraft.

See attached PNG of the Cuspid.

 

[Enoki]

I had another idea based on several designs I've seen in online games and anime where a ship or station is built using several asteroids that are held together by tethers, be it simple cables, or some sort of hollow, flexible tube.



A screen shot from the game Eve. It gives you the idea. This is definitely an outrigger type design.

 

[whartung]

re not understanding the concept of "outrigger" spacecraft.

See attached PNG of the Cuspid.

Sure, but what's the advantage?

Why complicate the design?

 

[Spinward Flow]

I had another idea based on several designs I've seen in online games and anime where a ship or station is built using several asteroids that are held together by tethers, be it simple cables, or some sort of hollow, flexible tube.

Sounds like a Dispersed Structure (configuration: 7) hosting additional Planetoid craft (configuration: 8 or 9).

 

[Grav_Moped]

Sure, but what's the advantage?

Why complicate the design?

Sometimes it's to better accomplish the design mission. A case in point (though I want to clean it up and make it a hybrid) was my 199Td composite collector drive yacht, which combined a 100Td Collector-drive starship with a 99Td shuttle. The shuttle can be 6G without needing to make the whole thing 6G, and the carrier can't really use a maneuver drive anyhow. Combined for Jump, they fit this category.

Sometimes it's to make a statement about the setting -- the Cuspid, mentioned above, is an example. Ok, on paper it's pretty much a high-G Launch with a Particle Accelerator. Nasty, but a perfectly reasonable and ordinary military small craft. Make it something bodged together from a 10Td launch, a 3Td particle accelerator barbette, and some other small craft's drive section and it shows that the setting is one where scrapyards are the only available spaceship construction infrastructure.

 

[Enoki]

Sounds like a Dispersed Structure (configuration: 7) hosting additional Planetoid craft (configuration: 8 or 9).

I would think the difference would be a dispersed structure would be one where the components are not linked in a manner that allows them to function as a single entity.
That is, an outrigger design is like a catamaran or trimaran, while a dispersed structure is more like a group of structures held together without a means to really act as one.

 

[Condottiere]

In theory, close structure, since the implication is that acceleration isn't really effected.

 

[robject]

Sure, but what's the advantage?

Why complicate the design?

That's the right question. Under what circumstances are these ships created and used?

I had started to think about it with two ideas: "modularity" and "support". Like the modular cutter, which is a complication of a small craft in order to allow custom modules to suit whatever mission.

But then think about a 200t Free Trader. Would we ever see two 100t hulls connected together? What are you going to do, put the payload in one hull, and the ops in the other?

Well, maybe. Is it a good idea? Not in the general case. But, maybe sometimes...?