General Drop Tank Tender?

[aramis]

The distance doesn't matter - if you can transfer the fuel from a drop tank to a ship you can build a pump/hose that can transfer at the same rate.
If the drop tank can make it to safety and thus be reused then a m6 ship with a hose will have no difficulty

the inefficiency of losing the fill-hose volume worth of fuel and the fill hose itself, when it's torn off and sent 90° away from the ship's course, is a problem.

 

[whartung]

1 minute @ 1G acceleration = 18 km of separation (180m x 100D)

Yes, the math is clear. It's always been clear.

What is not clear, and has never been canonized in detail, is "how long" things take" and "when things happen" with jump.

We don't know if when the last miligram of fuel is drained from the tank, the jump drive fires, or is it idle?

"Sir, drive is charged, we can jump any time." vs "Tanks are draining, 10s to jump...There's the slurping sound. Any time now, here we....EYAUGH!"

Add all of the connectivity lag, "margin for error", "Sir, the coupling is stuck!", etc.

So, having some "buffer" of fuel on board to handle that detachment and get away window, seems prudent. And to make the math easy, making it "1 Jump" worth of fuel is a nice, LBB handwavy guideline.

 

[Spinward Flow]

What is not clear, and has never been canonized in detail, is "how long" things take" and "when things happen" with jump.

We don't know if when the last miligram of fuel is drained from the tank, the jump drive fires, or is it idle?

I figure that's because such granuarity of the engineering tech detailing is kind of pointless when dealing with combat rounds that are either 20 minutes long or 1000 seconds long (choose your own LBB ship combat rules).
Snapshot uses 15 second combat turns (p1).
Mayday uses 100 minute combat turns (p2).

One other thing to point out about "getting separation" from a dropped fuel tank ... for ships with maneuver drives (ie. anything that isn't an XBoat!), the maneuvering power doesn't need to be on the drop tank.

The starship can "drop" the tank and then the starship accelerates away until >100D from the location of the dropped tank.
Move the starship, not the drop tank.
After all, the starship HAS a maneuver drive (offer not valid with XBoats ) ... why not make use of it?

Just for the sake of simplicity, I'm thinking that a Jump Sequence can "hold" its countdown for up to 6 minutes (1/10th of an hour) after consuming fuel to jump in order to continuously recalculate and verify all (known) navigation factors (up to the last second) AND verify that engineering is "all green" and ready to jump prior to Pushing The Button™ to make the jump. At orbital velocities, 6 minutes can make a pretty decent "fudge factor" difference when it comes to the alignment of jump shadows ("wait for it, wait for it ... NOW!").

For reference of orbital scales, a total solar eclipse of Sol by Luna as seen from the surface of Terra can last anywhere from 10 seconds up to ~7.5 minutes.

 

[Condottiere]

Tokyo drift to assist separation anxiety.

The ecks boat gets a push, and once the drop tanks are empty, releases them, and they all drift in different directions.

 

[coliver988]

Tokyo drift to assist separation anxiety.

The ecks boat gets a push, and once the drop tanks are empty, releases them, and they all drift in different directions.

well, different directions really depends on the release: if explosive, then yes, if just dropping the connection with nothing else they continue the same vector as a change in direction needs something to make it change direction.

and for the granularity: seems like a similar argument for a few things that we all go way overboard on. The rules don't go that deep but we enjoy playing with that level of below the scale of the rules. Seems to me I've read some quite lengthy posts getting to the pointless level. But interesting and chrome-worthy. I've probably posted a few over the years!

 

[whartung]

I mean, it's one of two things.

Tenders are either possible, and just not done, or just not explored in published materials, or...they're not possible!

I tend towards the former, but that's just me. I can see how they don't make sense militarily, at least for combat vessels (though Drop Tanks do, IMHO, for rare occasions), and how they'd only be used for large, commercial concerns, not stuff most "Travellers" would be hands-on with. But nice high-port background filler otherwise.

 

[mike wightman]

TAS News

L-Hyd drop ships have only been in service for the last dozen years in the
interior, being made possible by recent advances in the field of capacitor
engineering, a joint press release explained. Commercial vessels equipped with the
new generation of long-storage jump capacitors carry jump fuel in specially
designed L-Hyd drop tanks in excess of their rated tonnage. Upon conversion of the
fuel to the massive energy required for jump, the drop tanks are explosively
jettisoned through the use of break-away connections and explosive bolts. Jump is
executed when the remains of the tanks are a safe distance from the vessel.

Close on the heels of the joint announcement by General Shipyards and
Tukera Lines that L-Hyd drop tanks would soon be manufactured in the Regina
subsector, came word by express boat from the Imperial core that a decision has
been made to deploy Jump-6 L-Hyd drop tank express boats on all major express
routes. Initial feasibility studies indicate that such a system could average jump5.5
per week by executing maximum jumps where possible, and leaving current xboat
units to disseminate information between the new major relay points. The system
is expected to cut communication time to the lmperial hub to under 25 weeks.
The Initial System Deployment Schedule indicates that the Regina subsector can
expect to be fully integrated into the network within a decade.

Sadly GDW destroyed their own setting by concentrating on the Fifth Frontier War, so these developments, and the Forboldn project, were never expanded on.

 

[Spinward Flow]

Tenders are either possible, and just not done, or just not explored in published materials, or...they're not possible!

I tend towards the former

It's the former.

You can only "do" what the game rules say you can do ... so until details got published for how to make use of the options (L-Hyd Drop Tanks), they weren't usable. Basically, the whole drop tanks concept came along "too late" during CT's run to be incorporated into the most important publications of that era ... and the one that DID try to take advantage of it (the Gazelle class Close Escort) got overtaken by an overhaul in the rules (LBB5.79 vs LBB5.80) that made the details of the class a poor fit for purpose, let alone for use as an example of What Do™ (4 hardpoints on a 300 ton starship with 100 tons of drop tanks).

That said ...

That just means that the realm of what starship classes that are designed to routinely take advantage of L-Hyd Drop Tank services is completely wide open and awaiting (still...?) an intrepid designer willing to lay the foundational cornerstones to build up the edifice of how such an interstellar infrastructure support ought to be configured, defined and operated (beyond the answer of "it exists, whaddya want?").

Just because the published materials offer no precedents is similar to a saying in the legal profession ... absence of evidence is not evidence of absence.

Your mileage may vary, of course.

 

[kilemall]

Recent advances in capacitor engineering indicates that heretofore there is no margin, the capacitors fill up and jump now to avoid either exploding or losing power.

It also indicates it’s probably a TL15 thing, so only the advanced military or luxury/express ships can do it.

 

[Spinward Flow]

Recent advances in capacitor engineering indicates that heretofore there is no margin, the capacitors fill up and jump now to avoid either exploding or losing power.

L-Hyd drop ships have only been in service for the last dozen years in the interior, being made possible by recent advances in the field of capacitor engineering, a joint press release explained. Commercial vessels equipped with the new generation of long-storage jump capacitors carry jump fuel in specially designed L-Hyd drop tanks in excess of their rated tonnage. Upon conversion of the fuel to the massive energy required for jump, the drop tanks are explosively jettisoned through the use of break-away connections and explosive bolts. Jump is executed when the remains of the tanks are a safe distance from the vessel.

 

[Grav_Moped]

well, different directions really depends on the release: if explosive, then yes, if just dropping the connection with nothing else they continue the same vector as a change in direction needs something to make it change direction.

and for the granularity: seems like a similar argument for a few things that we all go way overboard on. The rules don't go that deep but we enjoy playing with that level of below the scale of the rules. Seems to me I've read some quite lengthy posts getting to the pointless level. But interesting and chrome-worthy. I've probably posted a few over the years!

Yes, you might be able to use orientation motors to spin the ship to sling the tanks away.

I don't know if it's been settled as to whether the ship's orientation at the time of jump matters. I think it does, for the setting-fluff of some versions -- but not necessarily others. If it does, you'll either need to stop the rotation or have very good timing.

 

[Spinward Flow]

Yes, you might be able to use orientation motors to spin the ship to sling the tanks away.

So ... sling them away like a trebuchet by spinning the ship around and releasing them?
That's ... not going to give you anywhere NEAR as much distance if the drop tanks have no maneuvering power of their own.

Let's say, for the sake of illustration purposes, that you spin your ship around ("wheeeee!" ) fast enough to (explosive bolts release) a payload @ 10m/s of throw velocity ("YEET!") but zero acceleration after release.
It would take 1800 seconds = 30 minutes to reach the 18km distance that a simple 1G acceleration for 1 minute could achieve.

Let's say, for the sake of illustration purposes, that you spin your ship around ("wheeeee!" ) fast enough to (explosive bolts release) a payload @ 100m/s of throw velocity ("YEET!") but zero acceleration after release.
It would take 180 seconds = 3 minutes to reach the 18km distance that a simple 1G acceleration for 1 minute could achieve.

I think you can see where I'm going with this (I hope).
Under MOST circumstances, it will require less time and fewer points of failure(!) to use explosive bolts to detach a drop tank and then have a starship accelerate away from the drop tank in a straight line using maneuver drive power than the alternative of trying to spin up, FLING the drop tank away WHILE spinning, then stop spinning and finally jump when the drop tank has been launched far enough away.



Also, some hull configurations (looking at you, Dispersed Structures!) aren't exactly ... ideal ... for spinning around to do a bit of "punkin' chunkin'" with an empty drop tank to fling it away.



Most starships have maneuver drives (offer not valid with XBoats!) ... you're allowed to make use of them.

 

[Grav_Moped]

Also, some hull configurations (looking at you, Dispersed Structures!) aren't exactly ... ideal ... for spinning around to do a bit of "punkin' chunkin'" with an empty drop tank to fling it away.

Could be worse:

Needle configuration, especially when the center of mass is far to the aft because of the drives...

 

[Spinward Flow]

especially when the center of mass is far to the aft because of the drives...

"wheeeee!"

 

[Condottiere]

If you can spin off drop tanks at ninety degrees while drifting forward, you narrow down the time required for it to be a hundred diameters away.

 

[kilemall]

Exactly which is why it’s a power retention for greater time capability and hasn’t been discovered hence TL15.

I would further posit this has been developed in conjunction with black globe technology as that is the new use for capacitors that can retain power safely for longer.

 

[Spinward Flow]

Exactly which is why it’s a power retention for greater time capability and hasn’t been discovered hence TL15.

Here's an idea then.

Once 0.1MJn fuel has been consumed in preparation to jump, a ship can "hold" before actually jumping ... 1 minute per Jn capability of the installed jump drives+computer model, whichever is lower (external loads retained through jump factor into this).

1. J1 capable drives can "hold" for 1 minute before jumping.
2. J2 capable drives can "hold" for 2 minutes before jumping.
3. J3 capable drives can "hold" for 3 minutes before jumping.
4. J4 capable drives can "hold" for 4 minutes before jumping.
5. J5 capable drives can "hold" for 5 minutes before jumping.
6. J6 capable drives can "hold" for 6 minutes before jumping.

No TL=15 nonsense required.

Heck, the Gazelle class is TL=14 (as per LBB S7 and S9) and it comes with drop tanks as a standard feature of the class ... so TL=15 required is already looking mighty suspect as an assumption.

 

[TamsinP]

Here's an idea then.

Once 0.1MJn fuel has been consumed in preparation to jump, a ship can "hold" before actually jumping ... 1 minute per Jn capability of the installed jump drives+computer model, whichever is lower (external loads retained through jump factor into this).

1. J1 capable drives can "hold" for 1 minute before jumping.
2. J2 capable drives can "hold" for 2 minutes before jumping.
3. J3 capable drives can "hold" for 3 minutes before jumping.
4. J4 capable drives can "hold" for 4 minutes before jumping.
5. J5 capable drives can "hold" for 5 minutes before jumping.
6. J6 capable drives can "hold" for 6 minutes before jumping.

No TL=15 nonsense required.

Heck, the Gazelle class is TL=14 (as per LBB S7 and S9) and it comes with drop tanks as a standard feature of the class ... so TL=15 required is already looking mighty suspect as an assumption.

Maybe the following instead:

1 + (Drive Rating - jump distance) + (TL of manufacture - minimum TL for drive rating) minutes of "hold"

So, a TL 15, J3 ship doing a 1-parsec jump would have a hold time of

1 + (3-1) + (15-12) = 6 minutes

Tl15, J6 ship doing a 3-parsec jump:

1 + (6-3) + (15-15) = 4 minutes

TL 9, J1 ship doing 1 parsec:

1 + (1-1) + (9-9) = 1 minute

That reflects both improvements to jump drives as TL increases and the fact that jumps shorter than drive rating would be using less capacitor capacity.

 

[Spinward Flow]

That reflects both improvements to jump drives as TL increases and the fact that jumps shorter than drive rating would be using less capacitor capacity.

A decent alternative take on the question.
The only downside that I see with it is that the paradigm for using it kind of fails if you aren't using LBB5.80 as the basis for your technological progression of drive capability (which LBB2 drives do NOT follow!).

So rather than relying on tech level, you're probably better off using computer model instead.

• 1 + computer model - parsecs to jump = minutes of "hold" available before jumping

Note that such a formulation would mean that model/1bis and model/2bis computers would have "zero hold time" available when jumping 2 or 3 parsecs respectively.

• 1 + 1(bis) - 2 (parsecs) = 0 minutes of "hold" available before jumping
• 1 + 2(bis) - 3 (parsecs) = 0 minutes of "hold" available before jumping

So a curious side effect of such an alternative (to your proposed alternative) would be that bis computers cannot make use of drop tanks when using maximum jump range due to a lack of "hold" time available for getting clear of drop tanks.

However, bis computers would be "just fine" when jumping (maximum-1) parsecs.

• A starship with a model/1bis computer jumping 1 parsec would have 1 minute of "hold" time available to get clear of a drop tank.
• A starship with a model/2bis computer jumping 2 parsecs would have 1 minute of "hold" time available to get clear of a drop tank.

Where things start getting interesting is when you start looking at the "top of the line" TL=15 military starships:

• 1 + 9(fib) - 4 (parsecs) = 6 minutes of "hold" available before jumping

 

[kilemall]

Here's an idea then.

Once 0.1MJn fuel has been consumed in preparation to jump, a ship can "hold" before actually jumping ... 1 minute per Jn capability of the installed jump drives+computer model, whichever is lower (external loads retained through jump factor into this).

1. J1 capable drives can "hold" for 1 minute before jumping.
2. J2 capable drives can "hold" for 2 minutes before jumping.
3. J3 capable drives can "hold" for 3 minutes before jumping.
4. J4 capable drives can "hold" for 4 minutes before jumping.
5. J5 capable drives can "hold" for 5 minutes before jumping.
6. J6 capable drives can "hold" for 6 minutes before jumping.

No TL=15 nonsense required.

Heck, the Gazelle class is TL=14 (as per LBB S7 and S9) and it comes with drop tanks as a standard feature of the class ... so TL=15 required is already looking mighty suspect as an assumption.

Given the operational advantages and the specifically newly developed capacitor capabilities, if it were TL14 it would have been in use for centuries. Looks like more of a recent retrofit to me.

Again, YUMV so everyone can do as they like. But given the RAW plus setting clues, points to a new tech and 15 is Imperial maximum. The new need for that quality for Black Globes ices it for me.