Planetoid Starbase

[Bardicheart]

I've been tinkering with an idea using the capital ship design rules and I'd love to hear others thoughts on this.

Here's the idea. Take a planetoid hull of say 100,000 dT as a starting point.

Give it minimal maneuver drive, say rating 1, no more than rating 2. So 1,000 dT for M-Drive 1

Jump drive is optional, but initially I'm pondering including it just for a feasibility study, J2 would need 3,000 dT

Power plant is rating 3 so it can mount fusion weapons and up to 300 bay weapons (which it won't have that many but that's the max). So another 2,500 dT for the power plant.

Fuel would probably be somewhere in the 15,000 to 35,000 dT range giving it up to a 12 weeks operation, one jump 2, and a couple hours of 1G thrust or some combination of that (since it wouldn't make jumps normally, the jump fuel could be used to extend its operation time or refuel smaller ships).

Next item is a huge hangar bay at 6,500 dTs. That's big enough for up to 5,000 dTs of ships to dock.

This is the core of the idea, the hangar / spacedock would effectively allow the planetoid to act as a Class B starport. Possibly a mobile one at that.

So far on my spreadsheet I've got around another 30,000 dt tons left for other systems, weapons, etc.

Assuming this would be some sort of mobile starbase, capable of repairing and building up to 5,000 dT of ship at one time, what else would it need for that function? I'm assuming and parts, such as jump drives, weapon systems, etc. used in construction would be built elsewhere, shipped in and assembled here. So I'm really just focusing on what kind of equipment would be needed and tonnages for that equipment to perform that function. I'm thinking machine shops, storage areas for parts, etc. but how much tonnage?

Once the actual shipyard is worked out I can figure out crew requirements, quarters, etc. from there.

So there you are, have at it. I'm looking for ideas, suggestions, etc.

 

[AndrewW]

You would likely be interested in the upcoming: Supplement 14: Space Stations.

 

[phavoc]

Are you wanting your mobile base to double as a battlestation? Otherwise you'd not need very heavy armament (it would be a waste of money, not really space).

Also, a planetoid hull would be cheaper, but you lose 15% for a standard hull, and 35% for a buffered hull. A mobile starport would be better off having more hull space, so going with a standard hull would give you that space back (you could select a distributed hull for cost purposes).

You could also think about having a two-part ship. Think of it like a battle-rider tender. Assuming you had a few of these bases floating around in a sector, you could justify the cost of moving them by creating a tender with the jump drives that would be responsible for moving the base between systems. When not working on the base, it could be used to transport outsized cargo's, disabled larger ships, etc. You never read about them in Traveller, but you know there has to be a couple of large transports to move the things that need to be moved. Like we have today on our oceans.

 

[Bardicheart]

To be honest what got me thinking about this was reading through Pirates of Drinax. It mentions the Navy coming in and pounding a pirate base when they find one. That set me to thinking, who builds all these pirate bases and what are they like? If its so easy for the Navy to pound one (an really who wants to stand up to a Batron?) then wouldn't avoidance be a better way to go? Also, where do all these purpose built pirate ships come from (i.e. corsairs), who builds those? If pirates could construct a base that could build smaller ships... say 100 to 5000 dT (the range for a class B starport) and if that base looked like a big chunk of rock until you got close... and if it could then jump out before the Navy arrives... that might work as a pirate base (at least as a vague theory). But we could have a whole debate about the strategy of that and how viable it is... not what I'm looking for here.

Besides, wouldn't necessarily have to be a pirate base. It could be part of a system defense, acting as home port for SDBs and a LOT of fighters, not only being able to repair them but build them as well... provided it has supplies. For a wealthy system it might be part of a larger defense setup.

And if you can do it with a planetoid hull, you could also do it with a more conventional ship hull, but all that is irrelevant without the basics of the hanger and shipyard worked out first... proof of concept as it were.

What I am curious about is just the feasibility of the base itself, what would it look like, what kind of equipment would it have to have, tonnages, etc. What exactly do you get when you buy that 6,500 dT hanger. Going by HG, the cost on that would be 1,300 MCr... just what does 1.3 billion get you? I'm guessing you get more than hangar doors and some umbilicals. Maintenance equipment and so forth, sure. But would just that be enough to qualify as a shipyard... probably not. So what else seems reasonable to add in order to convert it into a functional shipyard? I don't know of anything in any of my Traveller material that answers that so we'll be pretty much making this up. But, there's some smart and creative people hanging out here, I figure some good ideas are bound to come up.

So yeah, weapons and so forth for now are incidental. Turning that hangar into a functional shipyard is what I'd like help with. One that's solved, figuring out what sort of hull would be appropriate and other things is fairly easy.

 

[GypsyComet]

Next item is a huge hangar bay at 6,500 dTs. That's big enough for up to 5,000 dTs of ships to dock.

Sadly, geometry doesn't work that way. For only a 50% increase in volume to work the bay and the ship need to be a matched pair. A bay large enough to walk under and around the ship in, stand on top, etc. is going to start at 4 times the ship's volume, and that will still feel like a tight fit. A bay you can fly just about anything into for a landing is going to start feeling right at 10x to 20x, depending the usual shape of the hulls you want to park there.

For comparison sake, just one of the original Battlestar Galactica's flight pods is well over 200,000 dtons, using one of the more conservative estimates of its size (about which there has been much research and discussion), and it doesn't handle anything bigger than a shuttle.

 

[Bardicheart]

No arguments about the realism Gypsy, so I did some math to help me visualize this. Just trying to look at this another way, a 5,000 dT ship could be a cube 140m long, 50m wide and 10m high (oh no, its the dreaded flying brick! :lol: ), an admittedly unlikely design but just for reference lets say we wanted at least 10m of space beyond that. That gives us a cube 160m x 70m x 30m or about 24,000 dT... so maybe a shipyard should be at minimum 5x the max intended size and you're probably right about it needing to be 10x since few people are going to build convenient brick shapes (all those spiffy wedges and cylinders, etc.). 20x seems overly generous in this case, but might be a good number for a "normal" class B shipyard intended to build truly any design (vs. the intent here to mainly build smaller ships or act as an auxiliary yard)

So now the shipyard has leaped from 6,500 dT to 25,000 dT at minimum and probably should be 50,000 dT and a cost of 5,000 - 10,000 MCr (ouch!). I'm gonna need a bigger planetoid!

Granted such a shipyard would be more restrictive in the shape of ship you could build since you'd be somewhat limited by the shape of the hangar itself, but for smaller ships you could still build pretty much whatever you want. Besides, unless we go back to MT rules, Traveller doesn't usually do that much book keeping.

Also, what can we reasonably assume is included in that hangar? Cranes / manipulator arms and other maintenance and repair equipment seems reasonable and in line with the kind of repairs you can do "in the field". But, what kind of shop space should be added to turn what is still an over-sized hangar into an actual shipyard capable of doing construction / major repairs? Maybe 1,000 dT of workshop space for 5000 dT max capacity (equivalent to 250 workshops or one for about ever 20 dT and probably indicating at least 250 crew for just the workshops)?

 

[Bardicheart]

You would likely be interested in the upcoming: Supplement 14: Space Stations.

Just saw this, and why yes... yes I probably would! LOL Xmas present maybe? 8)

 

[AndrewW]

You would likely be interested in the upcoming: Supplement 14: Space Stations.

Just saw this, and why yes... yes I probably would! LOL Xmas present maybe? 8)

Yup, should be good for you.

Don't know if it'll make it out by then though.

 

[Condottiere]

1. Actually, drop a bunch of dwarves on a large enough asteroid, give them a blueprint and turn up six months later with the drives and other fittings.

Seriously, though, having a planetoid eliminates the need to assemble the station in orbit which removes it from a whole lot of bureaucratic hurdles and scrutiny, which would be one reason pirate bases would be popular variants, since all you need to do is burrow.

What authorities might do is keep an eye of unusually large purchases of life support equipment, much like we might keep an eye on chemicals and equipment associated with drug manufacture.

If you really want to know the cost of a planetoid hull, it's:

a. transport costs
b. mining equipment cost
c. salaries of the miners and support staff
d. gravity and/or inertial compensator plates
e. life support equipment


2. Interestingly enough, Star Trek has a number of examples of shipyards and docks. Building the ship planetside or in orbit both have a number advantages and disadvantages.

In this case, you're thinking of an internal facility, probably on camouflage grounds; going strictly by the rules, all you need is 130%, though what not be mentioned would be the space for stores and tools if this is an ongoing activity, so you'll have to maintain an inventory, as Just In Time is bound to disappoint.

Nowadays, ships tend to be assembled like modules, which makes a more open shipyard more ideal for larger projects.

If you turn off the gravity plates, or have grav lifters, you may not need cranes.

Also, if you build a cradle on the surface with a roof, you can be more flexible on the size of ship.

3. I think that the economics of modern piracy make the maintenance of large ships problematic.

 

[simonh]

Logistics is going to be an issue. Conventional shipyards will either have supporting manufacturing and raw materials infrastructure (metals, plastics, chemicals, tooling, workforce, food, entertainment for the workforce, etc) or stable supply routes to deliver them. A mobile facility would either have to carry all of that with it, move to where the sources of these things are, or have supply ships chasing after it wherever it goes trying to catch up to deliver them.

Do you have an estimate of the size of the workforce that would be required to man the spacedock portion of the ship?

It seem to me that operating this thing is going to epically expensive. Anything you can do to slash the cost is going to make a difference. Since it's mobile, it's main tactic isn't going to be standing and fighting, but running for it or preferably lurking beyond the fringes of patrolled space and never coming close to being caught.

One option would be to base this thing on an old abandoned planetoid hull colony ship, possibly even a sub-light vessel, or perhaps a refitted planetoid habitat used by asteroid miners. Re-fitting an existing ship should cut the costs a lot.

Simon Hibbs

 

[phavoc]

Keep in mind pirates aren't going to be building a ship that often. They are pirates, after all, and they practice piracy, or the taking of others' ships.

So their goal will probably be more along the lines of having a chop shop/repair base to convert ships into pirate-y ones. Arrr!

I'd suspect that they'd find a nice asteroid and burrow inside of it to make their initial hangar. And some work would be performed in zero-g vacuum, and if possible they'd have at least one hangar bay they could park a ship inside to do more hands-on shirtsleeve work. Wiring something up in a vacuum would suck. The enclosed hangar bay would have grav plating, while the vacuum area may, or may not (or might have a combination of both). And there'd be a number of larger rooms behind airlocks that could store large spare parts/salvage/scrap for future work.

 

[Jame Rowe]

I like the thought of planetoid starbases but would second the suggestion that they not have jump-drives.

 

[CosmicGamer]

I like the thought of planetoid starbases but would second the suggestion that they not have jump-drives.

My guess is that they were included because someone already had ideas rolling around in the depths of their mind as to possible uses for this.

I'm not one of those that has all the different Traveller materials that have come out since it's fruition, but I'd think some form of repair ship that travels with the fleet or mobile station that operates and moves with the front of newly acquired territory until the permanent station is established or mobile pirate base or some such may have already been introduced somewhere?

 

[Bardicheart]

You would likely be interested in the upcoming: Supplement 14: Space Stations.

Just saw this, and why yes... yes I probably would! LOL Xmas present maybe? 8)

Yup, should be good for you.

Don't know if it'll make it out by then though.

Well that's okay, I don't mind a late gift and if worse comes to worst I have a birthday in July so...

... what, can't blame a guy for trying! LOL 8)

 

[Bardicheart]

1. Actually, drop a bunch of dwarves on a large enough asteroid, give them a blueprint and turn up six months later with the drives and other fittings.

DWARVES IN SPAAAAAAAAAAAAAAACE LOL, I needed that laugh first thing in the morning. Thanks :lol:

Seriously, though, having a planetoid eliminates the need to assemble the station in orbit which removes it from a whole lot of bureaucratic hurdles and scrutiny, which would be one reason pirate bases would be popular variants, since all you need to do is burrow.

True, I've never quite understood why that was a requirement, other than it was a way to soak someone for hauling fees and was more convenient for the starport shipyard. Whether this was a pirate base, system defense base, mining base or something else; in many cases I think it would make more sense to do the construction where it is. Start with mining equipment and bore out a nice hollow space. Possibly offset costs by mining out valuable ore... so choose your chunk of rock wisely and it may help pay for itself.

What authorities might do is keep an eye of unusually large purchases of life support equipment, much like we might keep an eye on chemicals and equipment associated with drug manufacture.

Good point, assuming it is pirates and not the planetary government or a corporation or something else.

In this case, you're thinking of an internal facility, probably on camouflage grounds; going strictly by the rules, all you need is 130%, though what not be mentioned would be the space for stores and tools if this is an ongoing activity, so you'll have to maintain an inventory, as Just In Time is bound to disappoint.

Though I agree with Gypsy the more I think about it, you'd really need a minimum of 5x the max tonnage you want to be able to build in the yard to be reasonable, 10x if you want a reasonable amount of flexibility in configuration and even then you still won't be able to build just any configuration.

If you turn off the gravity plates, or have grav lifters, you may not need cranes.

True, though building in zero-G comes with its own set of problems and turning the gravity on and off could put stresses on the ship so... but hey, its Traveller, they got big manipulator arm things to move stuff... now just nod and smile... 8)

3. I think that the economics of modern piracy make the maintenance of large ships problematic.

Oh not going there... the economics of pirates works just fine, as long as you don't actually do an audit of it... just nod and smile... nod and smile. LOL

 

[Bardicheart]

Logistics is going to be an issue.

True, though it may have regular supply depending on who owns it... I'm starting to regret mentioning pirates. If this were an auxiliary yard as part of a system defense then the local system fleet would see to that. If it were a corp base or a mining operation, again, major backing to deal with that.

Do you have an estimate of the size of the workforce that would be required to man the spacedock portion of the ship?

That's part of what I'm still figuring and why I keep going back to the shipyard itself. How many workshops would needed, once I have some idea about that I can start working backwards figuring out what kind of support personnel would be reasonable, recreational facilities, operations crew, etc.

It seem to me that operating this thing is going to epically expensive. Anything you can do to slash the cost is going to make a difference. Since it's mobile, it's main tactic isn't going to be standing and fighting, but running for it or preferably lurking beyond the fringes of patrolled space and never coming close to being caught.

Definitely do not see this as a fighter / monitor. For combat it would be more like an auxiliary carrier... while it could launch fighters its not really set up for it. But it could have hundreds, maybe thousands of fighters in storage for resupplying the actual front line carriers who have taken losses. Or it could be home base to a lot of SDBs, which do the actual fighting while this base tries to stay out of sensor range. In those two examples its probably part of wealthy systems defenses, and so probably no jump drive but maybe a slightly better maneuver drive or maybe it does actually have launch tubes (hard to say til we figure out what the core elements are, i.e. the shipyard, storage area, crew requirements... once I know that I can start fitting other stuff in and see what I come up with).

One option would be to base this thing on an old abandoned planetoid hull colony ship, possibly even a sub-light vessel, or perhaps a refitted planetoid habitat used by asteroid miners. Re-fitting an existing ship should cut the costs a lot.

True, and as I noted above one idea for actually offsetting costs is to pick an asteroid that contains valuable ore, mine that out and use it to help pay for it. Though, I'm thinking radioactives might be a bad choice long term... (Strangely everyone stationed there tends to go bald...) 8) One idea I'm mulling over is perhaps this is a long term mining base that started as a hollowed out asteroid from mining. Corporate owned it can manufacture smaller mining ships, mining drones, etc. on site. It would also have large storage capacity, fuel stores, etc. plus recreational facilities for the miners, a company story (whaddya mean 20 cr for an egg!!!). It probably would have jump drives, when the system is depleted, it jumps to another system and they start over. Basically a mobile Class B starport as a long term investment, it might cost 20 BCr to build but over time it could recoup that many times over. Or maybe it belongs to a major corp like GSbaG who want an out of the way shipyard where they build and test new prototype designs... possibly military designs, examine a 50,000 yr old alien ship, etc. (maybe its an Imperial Navy base for the same use). I can think of a lot of possibilities beyond just pirates, that was just what sparked the idea and then I realized there really wasn't enough info in the books to actually design one and that go me to thinking (always a dangerous thing when I start thinking 8) ), so here we are.

 

[simonh]

Seriously, though, having a planetoid eliminates the need to assemble the station in orbit which removes it from a whole lot of bureaucratic hurdles and scrutiny, which would be one reason pirate bases would be popular variants, since all you need to do is burrow.

True, I've never quite understood why that was a requirement, other than it was a way to soak someone for hauling fees and was more convenient for the starport shipyard. Whether this was a pirate base, system defense base, mining base or something else; in many cases I think it would make more sense to do the construction where it is. Start with mining equipment and bore out a nice hollow space. Possibly offset costs by mining out valuable ore... so choose your chunk of rock wisely and it may help pay for itself.

Well, you can either move the rock to where the workforce, construction vehicles, tools, workshops, supply lines etc are; or you can move the workforce, vehicles, tools, workshops, supplies, etc to the rock.

And back again.

Simon Hibbs

 

[Bardicheart]

And now back after a brief temporary ban (apparently I failed my dodge vs anti-spam... drat! LOL)

Keep in mind pirates aren't going to be building a ship that often. They are pirates, after all, and they practice piracy, or the taking of others' ships.

You sir have clearly underestimated the rate at which people I game with are depleting the supply of pirates! :lol:

More seriously I wouldn't see the a pirate base version of this doing a lot of new ship construction, more in the way of repairs and maintenance, modifications, etc. Maybe swapping out and upgrading the maneuver drive for a Hemmy big block with super charger (or the M-drive equivalent), etc. And since it would technically be a Class B shipyard it could also do structural repairs and other things you couldn't do in just a hangar or "in the field". Given the lives pirates lead that could be quite handy (Alright Capt Bob, I'll patch up the structure... again.. but you really gotta learn to pick softer targets cause this old bucket won't take much more.).

So their goal will probably be more along the lines of having a chop shop/repair base to convert ships into pirate-y ones. Arrr!

A chop shop is another good use. Since the ships pirates raid are generally worth more than the cargoes they carry, if they could capture those ships, chop them and then sell them as parts that could potentially be quite lucrative. Or if they want to add new guns to existing ship it would be great for that too... just don't ask too many questions where that mil spec fusion bay came from... they get a little touchy about that.

And there'd be a number of larger rooms behind airlocks that could store large spare parts/salvage/scrap for future work.

Definitely need storage space, I'm thinking cargo area at least double the max capacity of the space dock. So if capacity is 5,000 dT, storage of at least 10,000 dT seems a good starting point.

My guess is that they were included because someone already had ideas rolling around in the depths of their mind as to possible uses for this.

Oh definitely, the more I consider this the more different uses come to mind. So far...
Pirate base / chop shop
Secret corp research / shipyard
Secret Navy research base / shipyard
Long term mobile mining base
System defense auxiliary shipyard and supply depot

So far its looking like maybe 300,000 dt asteroid
Send in miners to hollow it out and if the builders have been smart they picked one with valuable ore to help offset build cost. Probably not radioactives though, might be bad long term (strangely all the pirates are bald...).
As a planetoid we'd have up to 240,000 dT of space available
The shipyard / spacedock would take up 50,000 dT and have a max construction capacity of 5,000 dT (if that much isn't actually needed it could be smaller, I'm going with that for now because the construction range for a Class B is 100 to 5000 dT spacecraft)
At least 10,000 dT of cargo area for building supplies, spare parts, etc.
Probably at least 20,000 dT of fuel for a maneuver drive, operations, refueling ships; more if it actually does have a jump drive.

So that's 80,000 dT used up already leaving another 160,000 dT available and still a lot to add. I'm guessing its going to need a lot of workshops for fabrication and so forth.

Q: Does anyone have any info on real world shipyards? Say the size of the drydocks, number of machinists employed for a build of a specific tonnage? That might be a good starting place to figure out how many crew the shipyard might have. If we can say it has X number of machinist then that becomes X number of 4 ton workshops. Then work out from there supporting crew and so forth for the dock. After that figuring base operational crew, weapons, recreational facilities, etc. should be fairly simple.

 

[Bardicheart]

Did a little digging this evening on RW ship construction and came up with the following.

The Oasis of the Seas, currently the worlds largest ship is (as best as I can determine based on her dimensions and some VERY rough calculations) about 100,000 dT in size in Traveller terms.

It took 8 years to build her, vs a Traveller ship of about the same size and a new design taking only 4 yrs (HG p55; I guess advances in automation can account for that).

It took a total over about 8,000 laborers to build her, with somewhere in the neighborhood of 3,200 at any given time.

There were 241 km of piping used, 5,310 km of electrical wiring and 600,000 liters of paint! (Not really relevant, but I thought it was kinda cool to know)

A total of 181 "grand blocks" were used each weighing around 600 metric tons! I get a back ache just thinking about that LOL

Okay so working backwards using the 100,000 dT and 3,200 laborers, that's at least one "machinist" for every 31.25 dT Or we could round that off to 1 machinist / worker per 25 dT.

Using that as a base, a 5,000 dT shipyard would need 200 such machinist and 200 "spaces" of workshops at 6 dT each (Engineering workshop, p83 - Supplement 10 - Merchants & Cruisers: Repair Ship; seemed a reasonable example of a well equipped machine / fabrication shop) for a grand total of ...

1,200 dT of workshops and 800 dT of staterooms for the 200 workers just for the shipyard.

An yeah, I realize the above is making HUGE over generalizations and such, but this is Traveller, not NASA and all I really need is something that looks reasonably realistic on paper. Sound reasonable?

 

[Condottiere]

1. Hydroponic farm: saves on life support and logistics.

2. If you had sent gnomes, they'd take four months and present you with a new blueprint which shows how they altered the layout so it's more efficient.

3. I'm fairly sure hundred ton hulls are 3D printed.