Quick Jump Turnaround

[Terry Mixon]

@Hardwire asked this in the Ship Design Thread and I think it deserves its own thread, so I’m reposting it here.

What was asked:

Hello all, I am looking for information as to the cooldown of jump engines. If a ship has enough fuel to make 2 jumps how long must they wait after exiting one jump before they can enter another jump? I seen it somewhere but can't find it now. If you know what book and page this is discussed on I would appreciate it.

 

[CordwainerFish]

First place I'd look is both of the Starship Operator's Manuals and The Imperial Navy, which should return somewhere between two and four answers.

 

[Terry Mixon]

First place I'd look is both of the Starship Operator's Manuals and The Imperial Navy, which should return somewhere between two and four answers.

So true.

 

[Condottiere]

You tend to want to look around first, and take stock of your (current) situation.

You probably want to confirm that you are where you wanted to be, and that should eat up a couple of rounds.

As regards to the cooldown period of your jump drive, it's already had a week.

 

[Sigtrygg]

I can give you the CT answer easy enough:

"It is possible for a ship to make another jump almost immediately (within an hour) after returning to normal space, but standard procedures call for at least a 16 hour wait to allow cursory drive checks and some recharging."

 

[rinku]

At the very least, the Astrogator is going to need time to fix position and do their thing. But that's also concurrent with any drive stuff the engineer needs to do.

If the second jump doesn't need to be particularly accurate (say, a jump to somewhere unobserved in the target system) you could probably pre-plot it in Jumpspace, though. If it turns out you arrived wildly off course and it can't be used, no harm - just means doing what you would have done normally.

 

[AndrewW]

At the very least, the Astrogator is going to need time to fix position and do their thing. But that's also concurrent with any drive stuff the engineer needs to do.

That's assuming the astrogator isn't the same person as the jump engineer.

 

[CordwainerFish]

That's assuming the astrogator isn't the same person as the jump engineer.

And also assuming the engineer's tasks do not rely on the results of the astrogator's, which is not what I always envisioned.

 

[rinku]

I was just referring to unrelated tasks, like checking for damage, discharging tachyon buildup, replacing quantum, and whatever else gets done between jumps that they usually have a week to sort out. And of course - if the astrogator is also the engineer the tasks will be consecutive.

Whatever the engineer needs to do once the plot is ready and the ship is where it needs to be to jump, happens normally.

 

[Hardwire]

What is quoted as from CT is the closest that comes to what I was looking for. And truthfully that may be where I seen it.

I am trying to develop a system and I am looking for a drawback that would prevent the over use of it.

Let me see if I have how jump drives work. The drive rapidly burns fuel building a charge, then releases that charge to envelop the ship in a bubble of Hyperspace allowing the ship to move faster then light outside of normal space.

 

[rinku]

I don't yet have the MGT Starship Operator's Handbook, but the MegaT one goes into it in some detail, I think, and has all those useful MegaTraveller detailed tasks. I'll have a look.

Edit: Nothing there.

 

[Hardwire]

I don't yet have the MGT Starship Operator's Handbook, but the MegaT one goes into it in some detail, I think, and has all those useful MegaTraveller detailed tasks. I'll have a look.

Edit: Nothing there.

Looked in the Starship Operator's Handbook and even though it has a lot of stuff it didn't cover this.

 

[rinku]

There might be something in TNE or MegaTraveller proper. I'll check those.

 

[Hardwire]

Ok I have come to the conclusion that there isn't any official rule so I will just go with that fact. If I need something I will have to come up with it.

But thanks all for sharing your thoughts on this.

 

[rinku]

Nothing I could find in TNE. The MGT2e22 CRB only has this, which is similar to text going back to CT:

"If haste is called for, a ship may refuel at a gas
giant immediately and re-jump right away. This allows
the ship to make one jump per week but makes no
provision for cargo, passengers or local stops."

Since frontier refueling, or even docking at a starport and getting fuel there takes a certain amount of time (100D to fuel point, 100D to jump point), any between jump jobs would likely just be done in that timeframe.

Might as well use Sigtrygg's CT quote, wherever that comes from (I haven't found the source yet, but it sounds familiar).

 

[NOLATrav]

From 1 to 16 hours is pretty close to the 3D range of 3 - 18, so 3D hours, average 10 hours?…

If not truly rushed, reduce the roll by Eng (jump) in hours. Or make a skill check to reduce the roll based on Effect.

 

[Condottiere]

Generally speaking, if you already have planned an immediate transition with the remaining onboard fuel, someone would check on the jump drive, during that one week period while in jumpspace, while the starship is coasting, and the jump drive is switched off, instead of delaying that until after you have exited jumpspace.

Unless you used drop tanks, not that much gas would be left in the tank, so astrogation shouldn't be too difficult a task, so with a really skilled one, your starship should be able to jump again, fairly safely, fairly fast.

 

[Endie]

As a spin-off of a thought experiment on world evacuations for high-pop worlds (result: it probably takes years), I tried to build the most efficient mass transport that I could.

It involved a million-ton ship with modular payload modules (with cold-berthed passengers pre-loaded during the weeks between departures) that were swapped at each end to save time, and drop tanks (from memory, there are high reliability drop tanks available at TL15 but don't @ me on that!) pre-loaded with fuel, all serviced by tugs and tenders to keep the prime hauler moving.

However, with about 1.1 million frozen passengers aboard and a ship costing more than a third of a trillion credits from the loaded hull (and probably nudging half a trillion when you count the two sets of modules used for fast turnarounds and the drop tanks) on the line I presumed that they would still perform a full day of jump drive maintenance at each end (the relevant bit for this thread!)

Edit: I just checked and, presuming that the driver was some world-destroying threat, and that the navy might see a use in gigafreighter heavy lift capacity, I even built a 2 million ton version. I'm no ship build specialist so I'm sure that someone here could come up with more efficient than 3.3 million passengers in a 2MTon hull! Weirdly, it wasn't much more expensive than the 1 MTon version so I messed up one of them, for sure.

 

[Sigtrygg]

Appologies, I am forgetting not everyone on the Mongoose Boards has an unhealthy fascination with LBB:5 High Guard 1980 edition.

The quote < "It is possible for a ship to make another jump almost immediately (within an hour) after returning to normal space, but standard procedures call for at least a 16 hour wait to allow cursory drive checks and some recharging." > can be found on page 17.

 

[Hardwire]

Appologies, I am forgetting not everyone on the Mongoose Boards has an unhealthy fascination with LBB:5 High Guard 1980 edition.

The quote < "It is possible for a ship to make another jump almost immediately (within an hour) after returning to normal space, but standard procedures call for at least a 16 hour wait to allow cursory drive checks and some recharging." > can be found on page 17.

That is what I remembered, I just didn't remember that it came from the LBB back when I started playing the game. BTW I do miss the fact that you could actually die during character creation, at least I miss it a little. Still trying to remember where my LBB's are, I thought they were with my Space Opera books but I found those.

But thank you very much. This goes in line with what NOLATrev suggested above.