Jumping Fleets and tracking jumping ships

[Badbru]

Bearing in mind that I only run TNE rules with some personal mods which I hope I won't need to elaborate on. I have a few questions for the esteemed, learned Citizens out there;
1) How do fleets jump together? I mean subject to big ships possibly jump masking smaller ships they'd have to be huge vs tiny and close together I know but...more importantly what about the time variation between each ship in the fleet with the 32hours window of difference in possible jump times?
2)How does say for arguements sake the Aubaine system defence boat your PC's are running from when they jump determine what your possible destination system is in order to report it to system Naval forces?

I suppose some qualifiers as to why I want to know may be in order. Lets say the Ref col is setting up a raid in a Solee held system involving a Clipper a Victrix and MM Scout, I'd not want to be a member of the scout crew if it was the first vessel to arrive in system if my buddies weren't less than an hour behind me

As for the other situation, lets say my PC's were actually being good and were hot after a Guild ship that's just done some bad but they haven't replenished j fuel yet. They'd really want to know where that ship was going when it jumped.
What kind of a task do I set them to determine that?
My current "work arounds" are: for fleets all ships need to slave navigation to the flagship and only one navigator/astrogater plots for the entire fleet. Feedback on this would be good.
For Tracking an active sensor lock either ladar or AEMS is required. again Feedback please thanks

 

[ElHombre]

Badbru,

here's an idea as regards fleets jumping together. DGP printed this back in a digest. It stated that fleets jumping together can 'tune' their jump calculations so as to all reach the destination at the same time. the ships would then reach the target with about an hour's total difference. sorry, in english that means they would all jump-out within an hour. they made it a task based on a navigation skill.

 

[far-trader]

Hmm, that sparked an idea. What if you used the largest ship in your fleet as a destination jump-mask? Perhaps this is how fleet-jumps work.

What I mean is you link all the computers through the fleet computer (as designated) and it sets up the parameters for all the ships. Defining the order of the jumps and the timing of the same and feeding this directly to each ship's nav-comp. Then once everything is ready the fleet computer initiates the sequence and the first ship out is the largest and so on down to the smallest being last. Each ship is "drafted" in the jump-shadow of the larger one jumping just ahead of it and cannot pass it so the whole fleet is effectively chained behind the largest ship. Then when the first (and largest) ship emerges from Jump-space the other ships start dropping out behind it in the same order and timing as they went in.

There'd be a few things I'd require IMTU rules wise.

First the size of the fleet computer would have to be big enough for all the elements of the fleet treated as a single ship. The fleet computer wouldn't have to be on the flagship or even the first ship to jump but it should probably be seperate from the ship's regular computer and require it's own bridge but I'd allow the tactic without that requirement with some penalty to the Jump (i.e. more misjump chance).

On a misjump (and there should be a small increase in the chance, maybe the same as using drop-tanks) I'd probably roll a percentage or something for the amount of the fleet affected. That is maybe something like a d6+1 in 10% increments (for 20-70%) of the fleet comes out as expected with the remainder being affected individually by the misjump results. So you might have some of the fleet scattered or even destroyed.

Also this might only work for a fleet where you can order the ships so that each has a significant mass advantage over the one just behind it. Maybe 100dT for a working safe shadow with anything less adding to the misjump chance.

And of course this organization will take some time to set up, both for the computers and the actual manuvering of the ships while forming up. It wouldn't usually be an issue but it could be in some cases.

Just brainstorming here and not fully formed yet, by all means poke holes in the idea or plug up the ones you see

 

[aramis]

FYI, there is a reference in TNE's RSB that indicates one can calculate a jump from another ship's jump exit, so as to end up there.

It doesn't say you can find out where there is, just that you can follow them there...

as for jumping together, I assume that jump plots are two part issues:
1) The tumble needed in jump to get there
2) the field inputs needed to get the desired tumble.

IMTU, that narrow definition is a part 1 definition, ususally set an hour ahead of calc. It's transmitted, and everybody calculates part 2 from it.

The "Hour variation" is from the mornor variables of a second or two variance in jump starts, plus a few kilometers distance apart.

Then again, IMTU, I allow coordinating jumps for docked ships... one ship needs be the lead ship, but you can co-jump two jump capables IMTU, so that they share a single bubble. (If, for some reason, they dirft apart in J-Space, both misjump!)

 

[The Oz]

IMTU you can guess at a ship's jump destination by the following method.

From jump masking/shadowing you can tell what destinations he cannot reach because they are behind some object's 100D limit from where he currently is.

You can identify how much energy a ship is using for its jump, which (if you know the ship's volume in dtons) can be used to calculate how far a jump the enemy is making (although an insystem jump and a jump-1 look the same).

Usually that will be enough; there isn't often more than one available destination that he can reach at the jump number he's making. But if there is more than one, you can use his final normal-space vector to help take a guess. Since ships IMTU keep the same relative normal-space vector they had before jump when they come out, it's a normal practice for ship navigators to aim their normal-space vector to minimize the travel time to the destination upon emergence. So if the fleeing ship's vector points more at one possible destination than another, it's likely he's aiming for that star system (or he might be trying to fool you).

It is also possible to deceive potential pursuers by expending more energy (jump fuel) than necessary to make the jump intended. If you burn fuel for jump-3 but only make jump-2 it can throw the opponent off. Of course, you need to have that fuel to expend.

 

[Richard Saunders]

Originally posted by The Oz:
IMTU you can guess at a ship's jump destination by the following method.

From jump masking/shadowing you can tell what destinations he cannot reach because they are behind some object's 100D limit from where he currently is.

You can identify how much energy a ship is using for its jump, which (if you know the ship's volume in dtons) can be used to calculate how far a jump the enemy is making (although an insystem jump and a jump-1 look the same).
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This depends on which rule set your using.
1 - must use all fuel for jump engine size regardles of distance traveled.
2 - only use required fuel for jump used.
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Usually that will be enough; there isn't often more than one available destination that he can reach at the jump number he's making. But if there is more than one, you can use his final normal-space vector to help take a guess. Since ships IMTU keep the same relative normal-space vector they had before jump when they come out, it's a normal practice for ship navigators to aim their normal-space vector to minimize the travel time to the destination upon emergence. So if the fleeing ship's vector points more at one possible destination than another, it's likely he's aiming for that star system (or he might be trying to fool you).
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With jump one there are 4 hexs you coyld jump to.
with jump 2 there are 11 hexs.
with jump 3 22 hexs.
Dont know about you but if someone's chasing me the last thing i'm going to worry about is my target systems allignment (a short trip into orbit) if i survive i may worry about it after the screem to the system defences.
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It is also possible to deceive potential pursuers by expending more energy (jump fuel) than necessary to make the jump intended. If you burn fuel for jump-3 but only make jump-2 it can throw the opponent off. Of course, you need to have that fuel to expend.

Bye.

 

[The Oz]

Lionel:

You'll note I did say you could "take a guess," not make a 100% accurate prediction.

As for jumping into an empty hex, yes I allow it, but why would you do it, especially if you might not have the fuel to get out again? Maybe you do, maybe you don't, but usually ships jump to star systems.

As for using the normal-space vector, I specifically said that the fleeing navigator could try deception by assuming a vector not pointed at the actual destination. However, I also said that it was standard practice to do this, so if:

1) I'm trying to guess the destination of a ship that =does not know= it will be pursued, the navigator will probably not use deceptive tactics (and if he does, that is suspicious all on its own).

2) The target ship knows it's being pursued, the navigator may still align his vector to the destination out of habit (it's the professional thing to do) or the fleeing ship may =want= to minimize it's flight time in the destination system for some reason.

Anyway, this system can reduce the places you have to start looking for the chase. And it's all IMTU.

 

[aramis]

Jumping to empty hexes is CT canonical: In the Traveller Adventure (Big Red Book), the March Harrier gets fittd with inflatable tanks so it can get off it's J1 main, and on to another main. (The marches have two J1 mains that come to mind right off... the Spinward main, which includes Regina, and the aramanx main, which separates by J2 within the marches at several points.)

The only way to get the MH to Psaydi is by doing 2J1 off the coreward end of the spinward main, on to the neighbor system, then J1 on into Psaydi.

Lots of reasons to do jumps into empty space... especially for low jump vessels. If not for calibaration points, the 1st imperium couldn't have been as big as it was!

 

[Richard Saunders]

Originally posted by The Oz:
Lionel:

Hello Oz
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You'll note I did say you could "take a guess," not make a 100% accurate prediction.
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The best guess you can get would be 25%, Yes most people will back longer odds than that,
This is why pirates dont follow prey unless they know where the target is going and when (they attack as you enter a system (random chance???)).
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As for jumping into an empty hex, yes I allow it, but why would you do it, especially if you might not have the fuel to get out again? Maybe you do, maybe you don't, but usually ships jump to star systems.
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If you dont have the fuel it's suicide, but most people would take to the life pods in a system and hope to be picked up, the pirate is after the ship and cargo not the crew right.
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As for using the normal-space vector, I specifically said that the fleeing navigator could try deception by assuming a vector not pointed at the actual destination. However, I also said that it was standard practice to do this, so if:

1) I'm trying to guess the destination of a ship that =does not know= it will be pursued, the navigator will probably not use deceptive tactics (and if he does, that is suspicious all on its own).

2) The target ship knows it's being pursued, the navigator may still align his vector to the destination out of habit (it's the professional thing to do) or the fleeing ship may =want= to minimize it's flight time in the destination system for some reason.
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If the ship dosn't know its being followed your home and hosed, There would only be one destination that fits the jump co-ords.
If they know there being followed and dont want to be court and they have better than jump one your screwed, they have any one of 11 possible destinations and empty hexs look perfect to me.
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Anyway, this system can reduce the places you have to start looking for the chase. And it's all IMTU.

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Yes all games are in YTU so whatever makes the players and you happy is the only thing that matters, but i love discussing things like this, it gets the mind working and the blood flowing if only in the fingers.
If you where an Impi warship you could ask at the port what maps they got and how much fuel they bought and how much tankage they have (Customs search will tell you this), If they dont land (i can think of only three types of ship that would do this. 1 - Russian trawler. 2 - Merchant doing a jump through, but if they havn't left in a reasonable time they should be visited. 3 - Pirate.
For 1&3 you want to visit them as soon as possible and that would be why they jump out.
For 1 or 3 you do want naval HQ to know about it.
If pirates can get the goods to a market you cant stop it and the only ones you will catch are the unlucky ones or the ones that are dobbed in (probably by the competition).
All you need are 2 or 3 merchant ships and a greedy governor.
You only need to capture one ship and fly it 12 hexs then sell it and you make a lot of money thats without the cargo (think rebirthing a car).
The cargo is incidental to the profit.
Well thats it for this time.
Bye.

 

[Straybow]

Leading ship(s) jump masking those following...

Hmmm, the angle subtended by 100D of a ship (<100km) over a parsec is far too small to navigate. Precision required: better than one millionth of an arc-second. Long before the fleet arrives they will cease to be masked by each other.

 

[TheEngineer]

Hi,

guess the leading ships gravity caused jump masking effect is neglegtable, isn't it ?

Regards,

Mert

Jump plots may not be straight

 

[Rodina]

I've always preferred that fleets can jump so they are pretty close together, +/- 6 hours, but not much closer than that. While it's not exactly conveinent, I think it makes things more fun. A bold, strong admiral will -- as a matter of pride -- make sure her flagship arrives first and takes whatever beating comes her way when they arrive, cowardly ones will send other ships ahead to clear the path.

This also forces more of a choice between jumping in close to the enemy, for surprise (and high risk), or jumping fairly far out system to consolidate the fleet before manuvering.

 

[Commander Drax]

I think it was in the MegaTraveller Starship Operators manual that I read that ships entering jump would burn copious amounts of jump fuel, channeling the energy generated through a zuchai crystal array before directing it into the ships hull grid in a sequence pre generated by the ships computer as part of the jump plot created by the Navigator. The tremendous amounts of energy channeled through the lanthanum hull grid causes it to glow brighter and brighter before ripping apart the fabric of space and taking the craft across the jump threshold into jump space. Interested ships that scanned these emissions and hence the jump grid energising sequence would be able to use their astrogation software to reverse engineer a plot for their own jump engines and hence discover where the target ship was going, as the hull grid lighting sequence determines the final destination. A result of this is that departing fleets that are being pursued by the enemy frequently detonate missiles etc in the space between the leaving fleet and its pursuers as a way of confusing the sensor readings of the pursuers and hopefully misdirecting them.

In T20 there is also a reference to a squadron jump, which I interperate as a plot created by the Astrogator aboard the fleets flag ship and then passed to the other vessels ready for jump, with a slight variation in the plot for each vessel to account for its slightly different position in real space relative to the rest of the fleet. IMTU the ship's computers would then enact the sequence with each ship effectively slaved to the command ship, hence jumping together and leaving/arriving at exactly the same time.

This could be a rout if commo was jammed by the hostile force, cutting off individual ships from the flag ship, in which case the individual ships would be forced to generate their own plots and might make it to the destination system, but with normal jump variance.

This system could still work nicely in TNE as jump sequencing has been seriously simplified in order to make the computer systems virus resistant, in which case I would say that in any given situation there are only a certain number of jump sequencing commands such as 'Red Alpha Bravo' or 'November, Tango, Beta' etc, and plots, and options would be severly limited, allowing pursuers to easily guess where you're going, coupled with pre jump emissions and hull grid scans.

Hope it helps & Sorry for the lack of elouquence, (Tired, late etc & partially drunk!)

 

[TKalbfus]

But what if ship's can't jump together? For instance each ship starts out in a different position in space and each jump calculation is unique to that position in space where it starts, the errors are all random in time and space. The solution for a fleet in space is simple, you don't jump toward the 100 diameter limit of the target planet, instead you jump towards the outskirts of the system where each arriving ship is less likely to be detected. All the ships gather at a preplanned spot in the system and wait for all or most of the ships to arrive before starting the invasion. If it was Earth's system they were attacking, they might arrive in the vicitity of Pluto's orbit, and all gather at Pluto and wait for all the ships to arrive, then strike towards Earth.

 

[Andrew Boulton]

You might want to arrive closer than Pluto (a week to Earth @6g).

 

[aramis]

Even Jupiter is a day away for most combattants.

Thrust times are VERY important. Under TNE with HEPlaR, Jupiter is jump range for most ships.

 

[Straybow]

" Under TNE with HEPlaR, Jupiter is jump range for most ships."

Which it should be without gravitic drive or massive reaction mass tankage.

 

[Richard Saunders]

Hello.
I cant see any navy not having some way of task force jumping.
Maybe all ships "dock" to the largest and link all jump drives to it's computer, This means the control ship will need a computer of the required size to generate the jump/maneuver size of all ships, then when jump is initiated all jump enginees generate one field around the fleet, This would make one jump bubble for all ships so the miss jump roll would be at the worst ships mod, There would only be one roll but if a ship missed it's maintenance it adds 1 to the roll, if one ship is using unrefined fuel it adds one to the roll.
Under combat rules each ship would know the fallback position and would jump out independantly.
Basicaly all other ships become RIDERS with jump engines tied to the main ship.
Option 2 - one ship calculates all jumps and each ship jumps seperatly but the time spread would only be 2d6 with seven being on time 2-6 early 8-12 late by the difference. So the worst you could end up would be 5 hours early or late, with a better than 50% chance of being within 1 hour.
Bye.

 

[jwcarroll60]

Datalink for info sharing & combat coordination could be used to coordinate a task force jump and for station-keeping in formation. Set a great enough seperation inbetween the ships of the formation and there should be minimal chance for jump mishaps.

 

[Richard Saunders]

Hello Carroll60.
That would fall into system 2 jump, but what size program would you need for the datalink and how many extra comunications link would you need.
Bye.