House Rules, Starship Design

[whartung]

77 Bk2 pgs 5-6

A power plant, to provide power for one trip (internal power, maneuver drive power, and other necessities) requires fuel in accordance with the formula: 10Pn.
Pn is the power plant size rating, determined from the maximum drive potential table by cross-referencing power plant letter and hull size. The formula indicates amount of fuel in tons, and all such fuel is consumed in the process of a normal trip. A fully fuelled power plant will enable a starship an effectively unlimited number of accelerations (at least 288) if necessary to use the maneuver drive during the trip (as when miniatures combat is used to resolve a ship to ship encounter).

Simply, you need to refuel the power plant every "trip". This later morphed in to having enough fuel for 4 weeks, and an electric powered reactionless thruster.

There's also this caveat:

Fuel is also used by the maneuver drives of non-starships. When used in such vessels displacing under 100 tons (ship's boats, shuttles, pinnaces, etc) 10 kilograms (1/100th of a ton) of fuel is sufficient for 1G of acceleration for 10 minutes.

Which suggests that the smaller drives are NOT reactionless, which is distinct from the larger, starship drives.

So, still nothing that suggests M-Drives consume fuel, and certainly nothing that suggests Power Plants are fueled annually (unless you have very large tanks, of course).

In MT, Antimatter power plants had "year" durations for the fuel consumption (i.e. tons/year), whereas the fusion ones were tons/hour.

In TNE, Fusion PP fuel rates were in Kl/year/MW. A TL 15 Fusion 1000MW reactor consumed 100 kiloliters (no even .1 of a dTon) of LHyd/year.

 

[Grav_Moped]

77 Bk2 pgs 5-6

This is where the broken-ness of the LBB2 power plant fuel allocation started. '77 rules ships burned fuel like '77 rules small craft -- they just had an effectively unlimited fuel reserve because 10Pn tons was "more than you'll ever use," even though it was all used over the course of a two-week trip.

 

[Fovean]

My players would figure out how to run a 10,000 ton free trader.

That would be a trip… I loved Leviathan back in the day, it seemed so huge. But 10 kilotons, man… do freighters that big exist or would it be a retrofitted warship?

 

[Condottiere]

Probably; you could weld together some large hulls, if you can't get one big enough custom made.

 

[Grav_Moped]

That would be a trip… I loved Leviathan back in the day, it seemed so huge. But 10 kilotons, man… do freighters that big exist or would it be a retrofitted warship?

Small-ship universe (LBB2)? No... ok, maybe, with the Size Z drives and playing cute by stacking 5KTd hulls.
Big-ship universe (High Guard)? Sure!

They're not using LBB2/LBB7 trade rules, though; those generally don't generate enough cargo for ships above 600Td.

 

[infojunky]

77 Bk2 pgs 5-6



Simply, you need to refuel the power plant every "trip". This later morphed in to having enough fuel for 4 weeks, and an electric powered reactionless thruster.

There's also this caveat:

Which suggests that the smaller drives are NOT reactionless, which is distinct from the larger, starship drives.

So, still nothing that suggests M-Drives consume fuel, and certainly nothing that suggests Power Plants are fueled annually (unless you have very large tanks, of course).

In MT, Antimatter power plants had "year" durations for the fuel consumption (i.e. tons/year), whereas the fusion ones were tons/hour.

In TNE, Fusion PP fuel rates were in Kl/year/MW. A TL 15 Fusion 1000MW reactor consumed 100 kiloliters (no even .1 of a dTon) of LHyd/year.

You are spending too much time telling me I am wrong for the house rules I chose to use. Please note that a couple of odd forks of Travellerdom use similar power plant fuel regimes.

 

[Fovean]

It’s odd that there was never a supplement for Megacorp freighters and liners. That was the whole conceit of spacelanes and ostensibly the x-boat routes, no? The “regular service routes” of the subsector, where the thousands of dtons of cargo and passengers moved about in the background…

I guess GURPS took a pretty good swipe at the economics of it but only warships ever get the loving detail. What‘s the Tukera capital class money maker Tigress equivalent?

 

[infojunky]

It’s odd that there was never a supplement for Megacorp freighters and liners. That was the whole conceit of spacelanes and ostensibly the x-boat routes, no? The “regular service routes” of the subsector, where the thousands of dtons of cargo and passengers moved about in the background…

The Traveller Adventure covers some of that.

 

[Spinward Flow]

They're not using LBB2/LBB7 trade rules, though; those generally don't generate enough cargo for ships above 600Td.

Please clarify what you mean by this assertion.
Do the LBB2/LBB7 trade rules yield some kind of "optimal cargo sweet spot" above which there are diminishing returns on increased cargo capacity?

I would also note that with "overly generous" cargo capacity it becomes possible to "carry more cargo further" than merely the next system.
So instead of being limited to:
A -> B ... B -> C ... C -> D ... on a full/empty/full/empty repeating cycle
You can instead do:
A -> B+C ... B -> C+D ... where at each stop you pick up cargo for the next 2 systems to visit, not just the next 1 system
Which isn't quite as efficient as a pure full/empty cycle of shipments, but with large enough economies of scale you could pull it off. It's also better for the bottom line than jumping with a less than full manifest.

 

[Grav_Moped]

Please clarify what you mean by this assertion.
Do the LBB2/LBB7 trade rules yield some kind of "optimal cargo sweet spot" above which there are diminishing returns on increased cargo capacity?

Yes. Unless you roll LBB7 cargoes separately from LBB2 cargoes (it's not clear you can't, but it looks a lot like 7 supersedes 1), median cargo without modifiers (TL, pop, etc) is in the 200Td range. Enough to fill a canon Subsidized Merchant as written or a Subsidized Liner (running at a loss ex subsidy), but less than an optimized 400Td J1 freighter would hold.

Rules as written don't provide for through-carriage (load at A for delivery to C after passing through B). They don't even provide for delivery via sequential jumps (2J1 substituting for 1J2).

They're either broken, or merely describe the subset of interstellar trade that's available to small, independent merchants.

 

[Grav_Moped]

It maxes out at 2400Td cargo in the best case (maximum +DMs across the board, rolling all 6s).
Math here.

Without any mods: (it's two posts after the first link)
Median: 219Td
Maximum: 660Td

 

[Fovean]

They're either broken, or merely describe the subset of interstellar trade that's available to small, independent merchants.

It’s the latter, I believe. I can’t count how many times I’ve heard “the trade rules are written for players (adventurers), they don‘t model a galactic economy.”

Even B7, while it has Fledgling, Subsector and Megacorp lines for char gen, doesn’t differentiate in the cargoes available, or bulk pricing, through-carriage and so forth. An abstraction, sure, but a little chrome here could really help flesh out a campaign area.

 

[Spinward Flow]

It’s the latter, I believe. I can’t count how many times I’ve heard “the trade rules are written for players (adventurers), they don‘t model a galactic economy.”

Even B7, while it has Fledgling, Subsector and Megacorp lines for char gen, doesn’t differentiate in the cargoes available, or bulk pricing, through-carriage and so forth. An abstraction, sure, but a little chrome here could really help flesh out a campaign area.

Simplest solution would be to devise an extension to the rules ... which would of course not be RAW (but there you have it).

Incidental is D6x1 tons (1-6) per cargo lot.
Minor is D6x5 tons (5-30) per cargo lot.
Major is D6x10 tons (10-60) per cargo lot.

The obvious extensions for larger cargo sizes as an extrapolation would be D6x50 and D6x100 for the next two tiers.
I figure one of them would be named Bulk cargo (probably the D6x100 tons per cargo lot), but I admit to being at a loss for a good name for the d6x50 tons per cargo lot type.

As for random determination of how many cargo lots are available for shipment ... for the D6x50 ton lot type, simply use the Cargo table (LBB2.81 p11) using the Major Cargo type, except apply an additional DM of -1 for each rank of starport below B at the origin AND destination (so a type C to C starports shipment would involve a -2 DM in addition to all other DMs) and have no D6x50 cargo coming from or going to either Red or Amber Zones.

For the D6x100 ton lot type, simply use the Cargo table (LBB2.81 p11) using the Incidental Cargo type, except apply an additional DM of -1 for each rank of starport below A at the origin AND destination (so a type B to B starports shipment would involve a -2 DM in addition to all other DMs) and have no D6x100 cargo coming from or going to either Red or Amber Zones.

Such a formulation helps extend the quantities of cargo to be shipped "usefully upwards" in a way that doesn't require writing whole cloth new rules (by borrowing from old ones) and biases opportunities for extremely large cargo lots to being available on routes involving higher capacity starports which can handle such extremely large cargoes (hence the starport origin and destination DMs). It also means that the truly BULK cargo shipments (100-600 tons) are something that comes from higher population worlds only with large enough world economies to produce goods on that scale. Naturally, Industrial coded worlds will tend to be the most likely sources for truly high volume shipping opportunities.



How does all of that sound as a workable "house rule" to cover the gap in rules details?

 

[mike wightman]

Power plants using fuel as reaction mass is implied by LBB2 77

A fully fuelled power plant will enable a starship an effectively unlimited number of accelerations (at least 288) if necessary to use the maneuver drive during the trip

One burn takes 10 minutes - 6 per hour. So 288/6 = 48 hours of continuous thrust. Since 10,000kg of fuel is required (per g ) then you get 10,000/288=35kg of fuel used per burn for a ship, while we know that a small craft uses 10kg per g.

And since it flat out states in LBB5 79 that the m-drive is a fusion rocket then it is pretty obvious that the m-drive using fuel as reaction mass predates TNE, in point of fact it was the original intent, which was mentioned in interviews with the authors of TNE.

 

[Condottiere]

My interpretation of this is that fuel is treated like opportunity cost, you only have so much and if you use it up for manoeuvre, you can't jump.

I suspect that at some point someone realized that limits the scope for insystem exploration.

 

[Grav_Moped]

Power plants using fuel as reaction mass is implied by LBB2 77

One burn takes 10 minutes - 6 per hour. So 288/6 = 48 hours of continuous thrust. Since 10,000kg of fuel is required (per g ) then you get 10,000/288=35kg of fuel used per burn for a ship, while we know that a small craft uses 10kg per g.

And since it flat out states in LBB5 79 that the m-drive is a fusion rocket then it is pretty obvious that the m-drive using fuel as reaction mass predates TNE, in point of fact it was the original intent, which was mentioned in interviews with the authors of TNE.

And that's where the 10*M*Pn starship power plant fuel allocation came from: the kg/g (not kg/g*ton) fuel burn requirement in LBB2 '77.
The change to that basis in HG and then LBB2 '81 went without mention. Then, they didn't change the required quantity in LBB2 '81 even though they'd eliminated the reason it was a flat-rate by Pn rather than a percentage of tonnage by Pn.

"But maybe the rain
Is really to blame
So I'll remove the cause
But not the symptom"
-- Dr. F. N. Furter

 

[robject]

That would be a trip… I loved Leviathan back in the day, it seemed so huge. But 10 kilotons, man… do freighters that big exist or would it be a retrofitted warship?

They do in fact exist, but as you might guess, players don't really fly them. For one, they're too big.

But this is only in context of the Gentleman's house rules that limits capabilities of sub-10k ships. My players are obnoxious and obtuse about attempting to get what they want. (In other words, they're very good, engaged, players.)

...I could always give them a Nostromo-like ship.

 

[Spinward Flow]

...I could always give them a Nostromo-like ship.

Nostromo was basically a space tug+barge design.

 

[robject]

Nostromo was basically a space tug+barge design.

Or a bulk ore freighter. Matters not.

 

[Spinward Flow]

Or a bulk ore freighter. Matters not.

Internal vs external cargo "matters not" ...?

Didn't the Nostromo "ditch the cargo" in an attempt to save the (surviving) crew?
If the cargo is internal, that makes a lot less sense than ditching an external cargo.