It might also affect the distribution of starport types...
General Drop Tank Tender?
- Thread starter Spinward Scout
- Start date
Several reasons not to use them even if they are recoverable.
1.) The price is high. Takes profit away from the crew. Which could make the ship increase Passenger and Cargo costs.
2.) They are mostly used to traverse empty hexes. Or even getting 2 J2's quickly at least ignores refueling time.
3.) There's more of a possibility of misJump using them, if I remember right.
Condottiere
SOC-14 5K
Probably cheaper if you're vertically integrated, likely the military and a transport orientated megacorporation.
If it's fuel as a service, you'll be paying the full cost, possibly premium, for their processed fuel.
If it's fuel as a service, you'll be paying the full cost, possibly premium, for their processed fuel.
Spinward Flow
SOC-14 5K
Wilderness skimmed fuel: Cr0 per ton
Unrefined starport fuel: Cr100 per ton
Refined starport fuel: Cr500 per ton
Refined drop tank fuel: Cr600 per ton
And starport fuel doesn't?
Drop tanks can also be used to link together far flung type A/B starports.
- Boughene/Regina to Regina/Regina is 6 parsecs, so with drop tanks you can either J6 across that gap (with drop tanks) or J3+3 across that gap (with drop tanks).
- Jewell/Jewell to Efate/Regina is 6 parsecs, so with drop tanks you can either J6 across that gap (with drop tanks) or J3+3 across that gap (with drop tanks).
- Vilis/Vilis to Lanth/Lanth is 6 parsecs, so with drop tanks you can either J6 across that gap (with drop tanks) or J3+3 across that gap (with drop tanks).
- Lanth/Lanth to Adabicci/Lunion is 6 parsecs, so with drop tanks you can either J6 across that gap (with drop tanks) or J3+3 across that gap (with drop tanks).
- Regina/Regina to Paya/Aramis is 6 parsecs ... and Paya/Aramis to Aramis/Aramis is another 6 parsecs, so with drop tanks you can J6+6 from Regina/Regina to Aramis/Aramis, or J(3+3)+(3+3).
Transport services to type C- starports then becomes the realm of "free traders" and other lower end players in the market who operate starships that do NOT rely on drop tank services for interstellar travel. You get a sort of "break point" dividing line between the wealthier operations that concentrate on the A/B trade routes and "everyone else" fighting for scraps in the C- trade routes (which is where most PC held ACS operations will tend to be).
Different markets ... different game ... different rules on the space lanes to profitability.
Lack of reliance on a drop tank (or fuel tender) means that the ship can operate with less support.
Also consider a raiding situation. The raider fleet arrives and rather than destroying freighters, it destroys the fuel tenders, thus paralyzing the freighters.
I agree, however, if tenders were available, that they'd likely be ubiquitous in settled regions of the galaxy for routine trade operations.
I can also see a scenario where ships would routinely have the connectivity plumbing and emplace a more capable drive (J3 vs J2, say), but only have tankage for J2. But if the opportunity presented to utilize the J3 in a tender environment, then they're able to choose that.
Condottiere
SOC-14 5K
I think originally it was two twenty minutes turns, so less than forty minutes.
Currently, it would be less than six minutes, my estimate is three, in order to allow some form of processing in the jump drive.
Currently, it would be less than six minutes, my estimate is three, in order to allow some form of processing in the jump drive.
I think you can use demountable tanks to fuel the jump drive; it's the collapsible ones (aka fuel bladders) that you can't.
Rules-version dependent. You're in MgT, so yes. IIRC T5 doesn't slice time that thinly.
That's what the buffer tank is for. I just swagged one jump worth, but it could be anything. When the tender goes dry, it detaches and accelerates away while the ship continues to drain the buffer tank on board.
mike wightman
SOC-14 10K
There is no buffer tank - jump fuel is used directly from drop tanks. You can build a ship that has all its jump fuel in drop tanks.
So why not build your drop tank as a 99t smallcraft?
So why not build your drop tank as a 99t smallcraft?
Condottiere
SOC-14 5K
Less buffer, more prefuelled.
When you exit, you get your bearings, and jump again.
When you exit, you get your bearings, and jump again.
Spinward Flow
SOC-14 5K
Being able to double jump is an INCREDIBLY POWERFUL capability.
Being able to "round trip, without refueling" makes a whole host of previously INaccessible locations (go there, get stranded
) potentially viable as destinations. Likewise, being able to "jump across the gap" starts getting (almost) reasonable when dealing with various rift/abyss challenges, such as the Abyss Rift in Lanth subsector, or the Greater Collace Rift in District 268+Five Sisters.Depending on the details of the location (and where you want to go), something as simple as J2+2 can sometimes be sufficient ... while for greater distances, J2+3 or even J3+3 might be preferable for being able to traverse "large gaps" between star systems when there is no convenient location for refueling at (or near) the mid-point of the journey.
Being able to double jump for 4-6 parsecs of range (and charging 2 tickets for the transit, because 2 jumps) can make for a cheaper and more flexible option in starship design than reaching for a J4 capacity. Lower powered drives are cheaper (for starters), however, use of collapsible fuel tanks (and/or drop tanks) to enable double jumping enables a more flexible response to demand conditions, such that the capability for longer range is there "if you need it" for a specific transit, but when you don't you aren't operating an overbuilt "too expensive to live" starship that can't survive economically because of the compromises needed to get to J4, which will necessarily limit revenue tonnage.
Condottiere
SOC-14 5K
When I considered a rift cruiser design, optimum was three and three at technological level twelve.
Or, three and three and three.
Or, three and three and three.
Spinward Flow
SOC-14 5K
J3 @ TL=12 using LBB5.80 drives.
But yes, you're quite correct that a J3+3(+3) range allows you to do a LOT of ... Traveller(ing) ... before needing to refuel, which can make or break opportunities in locations such as the Riftspan Reaches, Verge and Reft sectors inside the Great Rift.
One curious emergent behavior from a J3+3(+3) range via drop tanks is something of an economic curiosity.
Under ORDINARY single jump "free trader" business cycle operations, you're doing a 1 week jump/1 week business tempo ... which amounts to 2 tickets per month (1 per 2, basically).
If you're double jumping, you're doing a 2 weeks jump/1 week business tempo ... which amounts to 2 tickets per 3 weeks (2 per 3, basically).
If you're triple jumping, you're doing a 3 weeks jump/1 week business tempo ... which amounts to 3 tickets per 4 weeks (3 per 4, basically).
The point being, by "jumping more" you're earning more ticket revenue per unit of time (1/2, 2/3, 3/4 = 6/12, 8/12, 9/12) while visiting fewer destinations (6 per 3 months, 4 per 3 months, 3 per 3 months). Depending on the "revenue tonnage" mix and how much cargo space an operator wants to reserve for speculation, you can wind up with some pretty radically different business model use cases as a result. The trick there is that passengers tend to be more "revenue dense" per ton of starship than cargo does in terms of ticket revenues, so if designed properly it might become possible for a multi-jump passenger liner starship class to carve out a niche role for itself double (or triple!) jumping past "jump over space" to reach distant destinations and still turn a profit just on ticket sales alone, with speculation in cargoes as a sideline.
Condottiere
SOC-14 5K
Your business model changes, if you have need a clear seven to nine parsec range, since the assumption would be that there is no possibility for refuelling.
So, whoever is chartering the starship would be very clear that passengers and cargo are going to be paying premium, so the passengers will have some need to pick this specific starship, with this type of performance; cargo will be tailored for what has a very high resale value at the other end, or urgently required.
Otherwise, you can stick to a tankless hull, and stay within the drop tank circuit.
So, whoever is chartering the starship would be very clear that passengers and cargo are going to be paying premium, so the passengers will have some need to pick this specific starship, with this type of performance; cargo will be tailored for what has a very high resale value at the other end, or urgently required.
Otherwise, you can stick to a tankless hull, and stay within the drop tank circuit.
Spinward Flow
SOC-14 5K
Maximum flexibility would be found with 1J* internal fuel + 1J* collapsible tank fuel + 1J* drop tank fuel.
That way, you only need to use the drop tanks when double or triple jumping ... and you only need to use the collapsible fuel tank when double or triple jumping. When single jumping, you're sacrificing a minimal amount of revenue tonnage capacity on the deflated collapsible fuel tank (1% of full capacity).
If you don't need that degree of flexibility, because you plan to go to A-B starports ONLY where drop tank services are available ... then yes, you can just outsource all of your jump fuel capacity to third party drop tank services.
Condottiere
SOC-14 5K
Cargo/fuel containers cost Cr5000 per ton of capacity and require 0.05 tons of additional equipment, for example a fuel/cargo container capable of carrying 100 tons takes up 105 displacement tons and costs Cr500000. A given tank/hold must be used either for cargo or fuel. It is not possible to mix cargo and fuel unless specialised containers are used, which will greatly drive up the cost. For this reason, fuel/cargo areas are typically constructed as blocks sufficient to fulfil a particular purpose. A ship might have a dedicated cargo hold, enough fuel for normal operations and one jump, plus one or more configurable areas each containing enough fuel for an additional jump. At the price of some capacity, such a vessel becomes vastly more flexible yet retains the ability to navigate between the sparse star systems of Gateway.
For more flexibility.
Essentially, if you want to look at it as cost outlays, the smaller the hull, the smaller engineering component is, which means you don't have to pay for engine capacity for the both that engineering capacity and fuel.
For more flexibility.
Essentially, if you want to look at it as cost outlays, the smaller the hull, the smaller engineering component is, which means you don't have to pay for engine capacity for the both that engineering capacity and fuel.
Missing the big picture methinks.
The point of the buffer tank is to finish fueling the jump after the drop tank/fuel tender is dry to give them a "buffer" of time to detach and get out of the way safely. Maybe there's no need. Maybe there's a 5-10m window after the fuel has been consumed for "things to get away".
The fundamental point being that if proximity to the ship is a problem, buffering the fuel consumption (via an onboard tank, however big it needs to be -- to a point) is a legitimate way to avoid that issue.
Spinward Flow
SOC-14 5K
- 1 minute @ 1G acceleration = 18 km of separation (180m x 100D)
- 2 minutes @ 1G acceleration = 72 km of separation (720m x 100D)
- 3 minutes @ 1G acceleration = 162 km of separation (1.62km x 100D)
- 4 minutes @ 1G acceleration = 288 km of separation (2.88km x 100D)
- 5 minutes @ 1G acceleration = 450 km of separation (4.5km x 100D)
Acceleration calculator found HERE ... in case anyone wants to Play The Home Game™ with this stuff (spoiler alert: you'll want to change the units being used from imperial to metric).
Note that a 180m sphere has a volume of V = 4/3πr³ ... so ... ~3,053,628m3/14 = ~218,116 displacement tons.
For reference, the 1200 ton Kinunir as published in LBB A1 has dimensions of:
- 73.5m Long x 52.5m Wide x 15.5m High (fin adds +11m High)
- 60m Long x 30m Wide x 12m High
For MOST of the ACS that PCs will be involved with, 1 minute @ 1G by recoverable drop tanks will usually be sufficient to create >100D of separation from a jumping starship. So, basically, anything smaller than a 30k ton Light Cruiser ought to be fine with a 1 minute @ 1G recovery boost back burn to get clear.
Anyone who doubts me, feel free to check my math.
