5 parsec gap in trade route

[rancke]

If you have a trade route with a five parsec link, what would be the cheapest way to cross it, with a jump-5 ship or a jump-3 ship with 50% fuel tanks? (Note: actual cost, not the per jump cost of Cr1000.) Or would there be a cheaper way still, perhaps involving deep space fuel depots?

The route is being used by only one company, so the company fleet can be tailored to the route.


Hans

 

[mike wightman]

If TL isn't a problem then jump 5 with drop tanks would be the cheapest way.

If TL is a limiting factor then jump 3 and build a fuel depot in an empty hex.

 

[rancke]

If TL isn't a problem then jump 5 with drop tanks would be the cheapest way.

If TL is a limiting factor then jump 3 and build a fuel depot in an empty hex.

Tech level is a concern and fuel depots require ships to ferry fuel, increasing the cost of the fuel. Fuel depots are much cheaper to build 1 parsec from a base system than 2 parsecs from one (Unfortunately, I don't have accurate numbers for the costs). Thus a jump-3 ship that has to cross a five parsec gap might need three jumps (one jump-1, one jump-3, and another jump-1), making the crossing more expensive per parsec.


Hans

 

[mike wightman]

Jump 3 with drop tanks then.

 

[polypterus]

I'm sure I don't know as much Traveller tech as a lot of you guys but I've always wondered why you just couldn't have booster boats that did the job of drop tanks on standard trade routs. Build a boat with a lot of fuel and big maneuver drives that hooks up to a starship, feeds fuel in and then blasts away at 6 Gs to clear the ship before it jumps.

 

[rancke]

Jump 3 with drop tanks then.

Yes, drop tanks are cheapest, if you can get them and if you can use them. But they are too recent an invention to be available here; the company is using ships without the capacitors you need to use drop tanks.

(They may also still be a business secret of the megacorporations or even just of Tukera).


Hans

 

[robject]

Credit-for-credit, it seems like the J3 drive will be smaller and cheaper than a J5. If you can wait an extra week for your ship, then that would seem best - maximizes cargo volume and minimizes price, but adds a week to travel time. Still need 50% for fuel, coming from somewhere.

That extra week is a deal-breaker if you're maximizing profit/loss, but you said you're minimizing cost, so.

Nonstandard alternatives (of dubious immediate value to you) might include...

(1) Finding a ten-billion-ton ice chunk midway and claiming it.
(2) Faking the stats for a Jump-2.5 drive.
(3) Slightly lower fuel requirements for advanced drives (assuming a Jump-3 drive built at TL13 requires 90% fuel, for example).

 

[aramis]

If you have a trade route with a five parsec link, what would be the cheapest way to cross it, with a jump-5 ship or a jump-3 ship with 50% fuel tanks? (Note: actual cost, not the per jump cost of Cr1000.) Or would there be a cheaper way still, perhaps involving deep space fuel depots?

The route is being used by only one company, so the company fleet can be tailored to the route.


Hans

Presuming CT-HG as the design system...
And both being TL14 (which includes PP issues - the TL12 J3 is the middle) collumn), the J3 TL14 is the winner.

Cost per cargo ton for transit of Cr5,732 on TL14 J3 with 200Td dedicated extra tonnage. if the spare tankage is collapsible, it's 2360/Td/Jump off route. (both before markup of 30% to match CT profits for J1 Bk2 designs)
Adding the 30% margin and then rounding to nearest Cr10: 5Pc Cr7,450 and 3Pc Cr3,070; in play I'd round these myself to Cr7500 and Cr 3100.

The TL12 1.66J3 is 7418/Td. Difference is lost tonnage to larger drives and the engineers they require.
The TL14 1J5 is 7839. Allowing a 30% markup, rounded to Cr10,190.

All are prices per cargo ton.
A mid passage would run Cr5310+4xTonnageRate (2084 amortization of the SR, 2000 LS, all x1.3 profit margin)
A high passage would run Cr5970+4.5xTonnageRate (to account for for the 1/8 sr for the steward) plus 1/8 the cost of the steward also marked up - Cr240 per person for a 2 week single jump.
Increase fixed costs in above by 50% to account for second week in jump.



This gives the 1j5 a HP cost of Cr52065 for that route. MP is Cr46070
This gives the 1.66j3 TL14 a HP cost of Cr42840 for that route. MP is Cr37765

The J5 is close enough to exist - as a priority run for people - being only KCr10 difference for the week. The costs of the steward add up quick.
Cargo or mixed runs will be the 1.66J3 run, where the




J/Mo ________________ 1.333 _________ 1.333 _____________ 2
Jn/Pn _______________ 3 _____________ 3 _____________ 5
Tons ____________ 1,000 _________ 1,000 _________ 1,000
TL _________________ 14 ____________ 12 ____________ 14
DesTL _______________ 0 _____________ 0 ____________ 13
Comp Model __________ 3 _____________ 3 _____________ 5

Tonnages ____________ 0 _____________ 0 _____________ 0
Bridge _____________ 20 ____________ 20 ____________ 20
Computer ____________ 3 _____________ 3 _____________ 5
JD _________________ 40 ____________ 40 ____________ 60
MD 1G ______________ 20 ____________ 20 ____________ 20
PP _________________ 60 ____________ 90 ___________ 100
Turret (1x1) ________ 1 _____________ 1 _____________ 1
Fuel, Jump ________ 500 ___________ 500 ___________ 500
Fuel, PP ___________ 30 ____________ 30 ____________ 50
SR _________________ 24 ____________ 24 ____________ 24
Cargo _____________ 302 ___________ 272 ___________ 220

Overage _____________ 0 _____________ 0 _____________ 0

MCrCosts ____________ 0 _____________ 0 _____________ 0
Hull 6 SL __________ 80 ____________ 80 ____________ 80
Bridge ______________ 5 _____________ 5 _____________ 5
Computer ___________ 18 ____________ 18 ____________ 45
JD ________________ 160 ___________ 160 ___________ 240
MD 1G _______________ 4 _____________ 4 _____________ 4
PP ________________ 180 ___________ 270 ___________ 300
Turret (1x1) ________ 0.2 ___________ 0.2 ___________ 0.2
SR __________________ 3 _____________ 3 _____________ 3

MCr Total _________ 450.2 _________ 540.2 _________ 677.2

Command _____________ 0 _____________ 0 _____________ 0
Plt _________________ 1 _____________ 1 _____________ 1
Nav _________________ 1 _____________ 1 _____________ 1
Engr ________________ 2 _____________ 2 _____________ 2
Gnny ________________ 1 _____________ 1 _____________ 1
Medic _______________ 1 _____________ 1 _____________ 1
Service _____________ 0 _____________ 0 _____________ 0

MoPymt ______ 1,875,834 _____ 2,250,834 _____ 2,821,667
AM Share _______ 37,517 ________ 45,017 ________ 56,434
Salaries _______ 22,000 ________ 22,000 ________ 22,000
Fuel, 2xJump __ 333,333 _______ 333,333 _______ 500,000
Fuel, PP _______ 15,000 ________ 15,000 ________ 25,000
LS, Mo _________ 24,000 ________ 24,000 ________ 24,000

Monthly Cr __ 2,307,684 _____ 2,690,184 _____ 3,449,101
Per Jump ____ 1,730,763 _____ 2,017,638 ___ 1,724,550.5

Per Ton _________ 5,732 _________ 7,418 _________ 7,839

Per Mo Cr/Td ____ 6,537.586 _____ 8,664.893 ____ 13,405.005
per J Cr/Td _______ 551.876 _______ 612.744 _____ 1,136.364



% Monthly __________ 85 ____________ 87 ____________ 85

 

[mike wightman]

If it's going to be a long term investment then why not use maneuver drives to move an iceteroid - 16 to 60 years to maneuver it depending on the fraction of c you consider canonical (0.25c for the Earth STL colony ships sent to the Islands and the Hinterworlds, 0.9c according to Imperium and Dark Nebula).

 

[aramis]

If it's going to be a long term investment then why not use maneuver drives to move an iceteroid - 16 to 60 years to maneuver it depending on the fraction of c you consider canonical (0.25c for the Earth STL colony ships sent to the Islands and the Hinterworlds, 0.9c according to Imperium and Dark Nebula).

In the long run, it's really cheaper and more monopolistic to carry the fuel aboard - building a station mid way requires additional hulls, maintenace, staff.

Note that the TL14 ship can easily be fitted with collapsible tanks in cargo tonnage and still operate competitively on J3 runs with J3 ships without such tanks.

 

[rancke]

Thanks Wil, that was a very comprehensive answer. I was wondering if the need to carry 20 percentage points of extra fuel in the cargo bay and to jump short on one of the legs would counter the advantage jump-3 usually has over jump-5.


Hans

 

[aramis]

Thanks Wil, that was a very comprehensive answer. I was wondering if the need to carry 20 percentage points of extra fuel in the cargo bay and to jump short on one of the legs would counter the advantage jump-3 usually has over jump-5.


Hans

The primary expense is the fuel and corresponding loss of cargo space - not so much the drive.

1Td of drive takes 10Td fuel. (usually)
1Td of drive costs MCr4, dividing by 240 to get payment, Cr16,667 per month per ton.

10 tons of fuel is, per jump, KCr5.

So the J3+2 is still the same 20% extra fuel as the J5, but it's also 1.5x the per unit time costs.

I'd go with the J3 with collapsible tankage.

 

[Selandia]

I'm sure I don't know as much Traveller tech as a lot of you guys but I've always wondered why you just couldn't have booster boats that did the job of drop tanks on standard trade routs. Build a boat with a lot of fuel and big maneuver drives that hooks up to a starship, feeds fuel in and then blasts away at 6 Gs to clear the ship before it jumps.

Its done. It is officially done in GURP and officiously done in CT. Usually known as LASH (lighter aboard ship -the eartly name it got from Sealand the cie that tried to introduce it as an alternative to containers-). In Traveller it combine a "Jump tug" (IMTU a starship w.o intrinsic significant cargo capacity) with powered lighters (space ships) or dumb lighters (cargo pod) that get loaded/unloaded at jump point. What you describe as booster boats (an alternative to drop tanks) I call jump tankers. There are no canon term for them that I know. The expensives Jump drive are therefore not iddle while in transit to/from planet and you carry cargo (lighters) rather than empty jump fuel space through jump. In MTU, the J-Tug has at least J1 fuel tankage so that the jump tanker can move away while the Tug burn the last part of its fuel before jumping.

Selandia

 

[polypterus]

Its done. It is officially done in GURP and officiously done in CT. Usually known as LASH (lighter aboard ship -the eartly name it got from Sealand the cie that tried to introduce it as an alternative to containers-). In Traveller it combine a "Jump tug" (IMTU a starship w.o intrinsic significant cargo capacity) with powered lighters (space ships) or dumb lighters (cargo pod) that get loaded/unloaded at jump point. What you describe as booster boats (an alternative to drop tanks) I call jump tankers. There are no canon term for them that I know. The expensives Jump drive are therefore not iddle while in transit to/from planet and you carry cargo (lighters) rather than empty jump fuel space through jump. In MTU, the J-Tug has at least J1 fuel tankage so that the jump tanker can move away while the Tug burn the last part of its fuel before jumping.

Selandia

I'm not sure I parsed everything you wrote but I just think the J-Tug makes sense in this case. You build a Jump-5, Maneuver-2 ship with only enough fuel for say Jump 2. It can be used as a far trader or alternatively with drop tanks or J-Tug It can Jump 5. Then you can do your rout in a single jump with 30% more cargo. With the J-Tug you save the cost of replacing drop tanks (Although assumedly they could be recovered and reused anyway) . At minimum it seems a lot easier than building a fuel depot in the middle of space.

 

[rancke]

I'm not sure I parsed everything you wrote but I just think the J-Tug makes sense in this case. You build a Jump-5, Maneuver-2 ship with only enough fuel for say Jump 2. It can be used as a far trader or alternatively with drop tanks or J-Tug It can Jump 5. Then you can do your rout in a single jump with 30% more cargo. With the J-Tug you save the cost of replacing drop tanks (Although assumedly they could be recovered and reused anyway) . At minimum it seems a lot easier than building a fuel depot in the middle of space.

Drop tanks is a recent technology. Over the next decades it will presumably change the nature of interstellar transport (if they can work out the kinks -- didn't MgT introduce some limitations? Or am I misremembering?). But right now they're still mostly using the old ships in the old way. Drop tanks require purpose-built ships. Most of the existing merchant fleet is unable to use them.

Drop tanks may even be a business secret of Tukera's still.


Hans

 

[Selandia]

Drop tanks is a recent technology. Over the next decades it will presumably change the nature of interstellar transport (if they can work out the kinks -- didn't MgT introduce some limitations? Or am I misremembering?). But right now they're still mostly using the old ships in the old way. Drop tanks require purpose-built ships. Most of the existing merchant fleet is unable to use them.

Drop tanks may even be a business secret of Tukera's still.


Hans

You are so right about the potential of change for liner service, that non canon limitation (and maybe canon in MgT, I do not know that system) are introduced by referee to explain why old patern of ships are used rather than drop tank (as another tread discussed at length ). Otherwise, the economic of starship service in CT is quite flimsy.

@Polypterus: Note that jump tanker and J-Tug are for liner service IMTU; it make sense in a repetitive system, with a fleet of M-Tug shuttling cargo pod, tankers that bring fuel, supplies and rotate crews. I do not believe that free trader could readily use tat systems, (except if they ride the J-tug for a long jump or for salvage).

Selandia

 

[aramis]

MgT introduces actual link-up hardware. Which makes Tug/Pod even less effective for routine operations.

In the real world, dedicated local shuttles are likely to be superior to atmospherically capable ships, on the basis of real aerodynamic hulls taking space for fairings and atmospheric controls...
... but Traveller doesn't have a landing gear cost, so the only penalty is operational time.

 

[nDervish]

Drop tanks is a recent technology. Over the next decades it will presumably change the nature of interstellar transport (if they can work out the kinks -- didn't MgT introduce some limitations? Or am I misremembering?).

Yes, it did:

- Ships require special fittings to handle drop tanks (1MCr and 2t of space per 50t of drop tanks)

- Penalty of (15-TL) on the misjump roll when using drop tanks

- At TL13 or lower, drop tanks are destroyed when jettisoned unless you roll 8+ on 2d6. At TL14, drop tank survival is automatic.

MgT also specifically states that "military assault ships sometimes use" drop tanks and makes no mention of civilian or commercial usage, for what that's worth.

 

[polypterus]

@Polypterus: Note that jump tanker and J-Tug are for liner service IMTU; it make sense in a repetitive system, with a fleet of M-Tug shuttling cargo pod, tankers that bring fuel, supplies and rotate crews. I do not believe that free trader could readily use tat systems, (except if they ride the J-tug for a long jump or for salvage).

Selandia

The original question stated "The route is being used by only one company, so the company fleet can be tailored to the route". Being able to carry 2X or 3x the cargo in a single jump probably makes the extra cost of ships and tugs worth it fairly quickly. I'm sure even with MgT ships it would be well worth it. However it's a game and the GM can justify whatever rules he wants to suit his needs. I just though I'd mention it

 

[atpollard]

Call me simple, but I'd run the numbers on a J1x5 ship with 40+ ton fuel bladders installed in the cargo bay at one end of the gap and removed at the other end (for installation on ships heading the other way).
[or a J2x3 ship if the main is not J1 outside the gap].

I suspect that I'd eat eat their (J3 or J5) lunch on the cargo trade.