Time in jump.

[mike wightman]

I am now convinced that a lot of us have been doing this wrong for years.

However, the advantages to a fleet which has not yet been detected by the enemy are immense. Suppose, for instance, that a fleet were to jump into a system with its black globes on and its velocity set upon a predetermined course. It could drift unseen past any defending fleet and drop its screens at a preplanned moment, to bombard a planet or to engage enemy fleets by surprise. Further tactical possibilities are left to the imaginations of the referee and players.

High Guard.

Note that the ships are jumping as a fleet.

Note also that if the jump duration is uncertain this tactic cannot possibly work.

Marc's Jumpspace article:

The duration of a jump is fixed at the instant that jump begins, and depends on the specific jump space entered, the energy input into the system, and on other factors. In most cases, jump will last a week.

The exact time of emergence is usually predicted by the ship's computer and the bridge is well-manned for the event.

.
I think that the variable jump time is a meta game construct for the ref to randomise how long the jump takes for fluff for the players.

The in game characters know exactly how long the jump should last, and an entire fleet can plot a jump together.

 

[aramis]

Note that in MT, there are actual rules (In MTJ, forget which issue) that specify the whole fleet arrives with a less random window...

IIRC, it's 1.68 hours of variability... ±1:40:48 instead of ±16:48:00. The not explicit is that the 2:21:36 window is centered on the 33:36:00 window randomization.

 

[far-trader]

I am now convinced that a lot of us have been doing this wrong for years...

<snippage of familiar words >

So, my brainwashing is finally sinking in... excellent :devil:

 

[mike wightman]

Yup, I can not see how the jumping with black globes up tactic can work unless you know your position and time of arrival to within a small margin.

I think somewhere someone got metagame and in game mixed up...

 

[pendragonman]

I blame alcohol induced GMing...

 

[BytePro]

Don't recall any roll mechanics for the time range in the original CT books (1-8), so just took jump time to be varying, but not necessarily random. <shrug>

For my TU, created a formula (decades ago) to account for the range of time stated in the CT books. Based it on origin and destination systems, so these times are the same when traveling between systems from a given direction (it ties into a 3D mapping). If someone departs 2 hours from you, they arrive 2 hours later than you. And Fleets can arrive together (much more dramatic IMO).

But I can also see it as a totally random thing - MgT has 148+6d6 hours.

 

[Magnus von Thornwood]

So about this black globe...

:devil: Ref Hat On!

So, let me get this right, you want to Jump the Fleet with their black globes on...hmmm.

Okay, first we look at does the black globe encompass the J-Bubble, if it does I am thinking that you don't jump. Fuel gets used, sparks fly (because it's cool and I saw it on TV ), thumps, bumps, groans and buzzing as the J-Drive tries to push the bubble outside the globe. Since Traveller Jump Drives work on volume not mass the J-bubble has to encompass all the volume Jumping.

So what's next, Jump Bubble encompasses the black globe that absorbs all energy? That black globe you wanted to have going when you Jumped? Whoops, guess what eats your J-bubble and cue the above effects. No Jump for you.

And if you got a Jump Grid system, no joy.

Yeah, I just don't see how this works. Explain it again, could you?

Then assuming you decide you still want to try, let us get to the black globe and Jumpspace. *sigh* I don't see that ending well. But if you do survive and the BG doesn't overload, I am pretty sure the Jumpspace Institute would love copies of your black box data.

As for the timing issue, shouldn't be that big a deal, I mean you are a space navy. Timed and Tuned Jumps were mentioned in the T5 drafts which were basically as tight a Jump you could get. So, yeah the Fleet should be able to make the same window barring mishaps.

Laterness,
Craig.

 

[far-trader]

So, about that black globe drift tactic...

...here's how it works.

I agree, the implications of the tech (BG and Jump) are that one can't actually jump with the black globe active (that might even be explicitly stated somewhere, I seem to recall), nor turn it on while in jump imo (seems obvious), which isn't necessarily what the statement says though:

Suppose, for instance, that a fleet were to jump into a system with its black globes on and its velocity set upon a predetermined course. It could drift unseen past any defending fleet...

Note my bold text. The fleet doesn't engage the globes until they precipitate IN the system. No interference or issues of mixing the BG and Jump tech. And they still drift unseen past any defending fleet which tells us a couple more things about jump.

First, there is no jump flash on arrival (I'm fine with jump flash on departure, why not). Let me repeat that to insure the brainwashing is reinforced :devil:

There is NO jump flash on arrival.

And now subliminally...

There is NO jump flash on arrival.

Second, the timing is critical to a very very very fine degree. No sooner does the ship emerge from jump space than the black globe is operating. Otherwise detection would be almost certain for a defending fleet. In fact it has to so precise as to be simultaneous. That IS how well known the exact duration of jump must be for all of this to work. Heck even for jumps to work safely without worrying about popping up a BG on arrival.

Third, BGs have no activation time.

...however, I don't think the rules are an example of confusing meta-game and reality, I think they were just the result of not appreciating the interaction. Marc has clearly stated that he intended jump to be a random duration in (game) reality. And that can't work with other equally clearly stated effects. Perhaps we just don't fully grok the way they are supposed to mesh. For me though, the meta-game solution has long been the way to "fix" it

 

[mike wightman]

Ahh, but the quote says it is jumping into the system with its black globes on, it does not say it jumps into the system then switches on the black globes.

There was a Challenge article about ships designed specifically to do this... have to go and dig it up.

 

[Orr]

There was a Challenge article about ships designed specifically to do this... have to go and dig it up.

It's not a Challenge article. You're thinking of Project Blackheart and the Nemesis-class ships in one of the DGP magazines.

Aren't you also forgetting the huge range of Traveller weapons too? Ships can aim lasers at distances greater than Earth's 100D jump limit. If you jump to a point in front of a world's orbital course, you're almost certain to come out within weapons range or very close to it.

 

[mike wightman]

That's the one - thanks for jogging the memory.

Weapon range depends upon the paradigm you adopt. If you use the LBB2 weapon range then lasers/beams weapons fire at light second ranges.

If you use the Mayday/High Guard conversion rules in Mayday the weapon ranges extend to 15 light seconds.

The Earth's 100D jump limit is 1280000km or just over 4 light seconds - well within short range

 

[Orr]

That's the one - thanks for jogging the memory.

You're welcome. I was reading it just a few months back.

Weapon range depends upon the paradigm you adopt.

I guess I'm more familiar with original Traveller. The ranges do vary from Mayday to High Guard to Book 2, but aren't they kind of close to each other? IIRC, one doesn't have a range limit stated. Instead the negative DMs for range limit fire.

 

[aramis]

You're welcome. I was reading it just a few months back.



I guess I'm more familiar with original Traveller. The ranges do vary from Mayday to High Guard to Book 2, but aren't they kind of close to each other? IIRC, one doesn't have a range limit stated. Instead the negative DMs for range limit fire.

HG doesn't give ranges at all - just short, long, or escaped.

CT Bk2 has ranges limited by DM totals - but you can hit out to a couple LS.

Mayday has much longer ranges (and a different time-scale), AND gives a tie-in to HG's defined ranges as a number of hexes... and they're impressive ranges at that.

 

[dean]

"The duration of a jump is fixed at the instant that jump begins, and depends on the specific jump space entered, the energy input into the system, and on other factors. In most cases, jump will last a week. "

HG Pg 17 states: "Any jump, regardless of number, takes approximately one week (150 to 175 hours);" ... "the speed and direction which a ship held prior to jump is retained when it returns to normal space."

There's also nothing in these passages that ALSO precludes jump time having a randomness to it. However, there is also nothing preventing "other factors" from being manipulated so that the the emergence time cannot be calculated and manipulated so that a fleet and enter into a system at a predicted time, within a few seconds or so.

I'll suggest that interstellar navies spend a lot of time studying, tuning and calibrating equipment for, and practicing this. Merchants, who really have no reason to care or need to do this, probably take the randomness as a matter of course and just go with it. Most civilians probably just think that the "randomness" is normal and unpredictable, and the navy folks like it that way just fine.

 

[rancke]

Since the process is entirely imaginary, there's no way to do it wrong in one's own TU. The only way to get it wrong is to be writing material for the OTU. And even then it's a matter of opinion (Marc Miller's opinion). For example, whoever wrote the bit about all the ships in a fleet being able to coordinate jumping into a system at precisely the same time could be right. Or the half dozen (or however many they are) who wrote about the duration of jumps being subject to a random time element could be right.

At best we can say "If this bit is right then that bit can't be and vice versa (and I like that bit better than that bit)".

Personally, I like the random time element bit better than the coordinate fleet bit. I like the tactical complications introduced by fleets being forced to arrive in a system spread out over a span of time. And if that means they can't arrive cloaked by black globes and perform a precision drive-by attack, the loss (IMO) is minimal, since black globes are rare enough to make an entire fleet equipped with them rare indeed.


Hans

 

[Icosahedron]

IMTU I sidestepped all that by inventing a nice little formula for Jump Time:

T = cu rt (D + c^2)

all in SI units.

All travel over Traveller distances takes 'about a week' (5-8 days).
Jump Time is fixed for a fixed distance, so synchronised Jumps are possible.
Delays in Jumping will result in fractionally altered times depending on stellar and planetary motions, resulting in new calculations.
Players can't/won't do the maths so they let the Ref tell them when they arrive.
I also decided that:
Arrival is without flash and at zero velocity wrt the nearest gravity well (no near-c rocks).
'Quantum Fluctuations' may or may not affect the journey time at the whim of the Ref.

Works for me.

 

[MR TEK]

I have pointed out before that t20 suggests that fleets can maneuver and jump together and arrive in a coordinated fashion. by using the same jump solution.

It also suggests that a potential jump plot generates many possible solutions, and that in some unspecified way a skilled navigator can select a specific solution to closely control either the duration of the jump, or the proximity to the expected arrival point.

 

[dean]

IMTU I sidestepped all that by inventing a nice little formula for Jump Time:

T = cu rt (D + c^2)

all in SI units.

All travel over Traveller distances takes 'about a week' (5-8 days).
Jump Time is fixed for a fixed distance, so synchronised Jumps are possible.
Delays in Jumping will result in fractionally altered times depending on stellar and planetary motions, resulting in new calculations.
Players can't/won't do the maths so they let the Ref tell them when they arrive.
I also decided that:
Arrival is without flash and at zero velocity wrt the nearest gravity well (no near-c rocks).
'Quantum Fluctuations' may or may not affect the journey time at the whim of the Ref.

Works for me.

Is the zero velocity rule just a handwave or is there a justification?

 

[Icosahedron]

It's a convenient handwave with some logic and technobabble backup.

I figured that since 'Jump Space' is essentially extra-dimensional and cannot communicate in any way with real space, there is likely to be a 'disconnect' between it and the rest of the universe.

Speed and Direction are forms of 'information' and cannot be retained in or 'communicated' through Jump Space. The logical corollary is that the speed and direction information of any ship is neutralised by Jump space and all ships arrive with a 'zero vector'. The question then arises 'zero wrt what? and again, logic and a dislike of near-c rocks suggests 'zero wrt the local G-field.

Otherwise, you have to start thinking, do my 'vectors' include the speed of the two planets in orbit, or the speed of the two stars through space? There has to be some degree of using the 'local region' of the journey's start and end points as a frame of reference, so why not make it an absolute and cut out all the headaches?

 

[savage]

Ahh, but the quote says it is jumping into the system with its black globes on, it does not say it jumps into the system then switches on the black globes.

Yep. So you turn them on when your about to leave jump space. As i recall from my Traveller library, Real time might vary but jump time is standard.