MegaTrav Fighter patrols

[Carlobrand]

So I'm beginning to take a look at MegaTraveller. I'm certain they could have made it more complicated if they really worked at it.

A lot of it is derivative of High Guard - a few changes, but no great trouble there. Some interesting new ideas. At any rate, I'm looking particularly at the sensor rules. Much complexity, but if I begin from the assumption that any space navy worth it's salt is going to have the most effective sensing equipment they can manage, then it looks like it boils down to this:
*Everyone (military) has an Active Object Scan of 7+ and a Active Object Pin of 7+ - just the lower tech folk have to spend a bit more for the privilege. That's vulnerable to jamming, but jamming seems to light you up for the energy scan.
*Passive Object Scan/Pin ranges from 15+ at TL10 to 7+ at TL15. Seems like the densitometer's really only practical around TL14+.
*Most everyone has a Passive Energy Scan of 7+; the TL14-15 folk have a Passive Energy Scan of 3+. This can be rendered less effective by EM Masking (you are treated as if you're a size smaller - it's equivalent to a -2 penalty), but not if the person with the masking is banging away with his active array. Passive Energy Pin ranges from 15+ at TL10 to 7+ at TL15; again only really practical around TL14+.
*Positive modifiers exist for skill and education characteristic (a piece of it, anyway). Negative modifiers exist for range (in 25 thousand Km units).

Now, if I assume the average sensor tech has an average education (less than 10) and at least a skill of 2, then in most cases the maximum range of detection (requiring a roll of 12 on 2d6) is about 150 thousand Km (6 range bands) for fighter-size/output craft, 200 thousand Km (8 range bands) for roughly destroyer-size/output craft, and 250 thousand Km (10 range bands) for anything bigger. Movement rules allow changes of one range band per g-rating, so a 6-g attacking fleet could conceivably close from extreme range to near range very quickly unless the defender was also fast and sought to maintain range.

All of that leads up to this: if I'm a fleet admiral facing these rules, I'm going to put out an inner perimeter guard of destroyers and an outer perimeter of fighters, far enough out that my main fleet assets won't suffer from any surprise. Since each craft rolls for sensors, a squadron of fighters has a better chance of spotting out at extreme range than one or two ships - and conversely they'll be harder for the enemy to spot, so they've got a fair chance of warning me and withdrawing safely. (And if they get caught, I haven't lost much.) The enemy will likely do the same - lead with squadrons of harder-to-spot fighters - in this case, hoping to destroy my fighters or prompt them to withdraw before they can gain any useful intelligence about the rest of his fleet.

So: 1) do I understand that right, and 2) does the game mechanic allow for such layered defenses?

 

[McPerth]

You must take into account that the enemy fighters/fleet can come after some turns of acceleration at high speed (let's say at a relative speed of 20, after 4-5 turns of 4-5 G acceleration, and so closing before you may even roll for detection and make the first attack run at high speed before overpassing your fleet and turning back for the rest of the battle.

This is mostly feasible if they know where you'll be (e.g. to atack a fleet known orbiting a planet or skimming for fuel) or they have a forward observer (either a undetected drone or some trojan horse ship) to tell where defending fleet is.

 

[Carlobrand]

I think I misunderstood computers. I'm used to an attacking computer - defending computer setup, but that appears to apply only to the attack rolls; sensing rolls are sensing computer - range. Therefore, a ship based on a Computer model 8 or 9 would have a couple hundred thousand kilometers longer range (+8 to 9 range bands) than what I estimated, and fighters - having smaller computers - would have shorter effective sensing ranges than the destroyers and battlewagons. Therefore, with a Model 9, say 375 thousand kilometers maximum detection range (15 bands) to detect a fighter, 425 thousand (17 bands) for a destroyer, 475 thousand (19 bands) for a cruiser or destroyer.

That makes the destroyer screen more useful - model 9s on a platform that enjoys a slight stealth advantage over the battlewagons (19 vs 17 bands). Also means the Imperial 50-ton fighters, with their model 7-cum-6 computers two ranks below those of the typical TL-14 opponent, still have a slight edge against the battlewagons (16 vs 14). Does trash my initial thoughts about using 10-ton minis, though. Sigh.

You must take into account that the enemy fighters/fleet can come after some turns of acceleration at high speed (let's say at a relative speed of 20, after 4-5 turns of 4-5 G acceleration, and so closing before you may even roll for detection and make the first attack run at high speed before overpassing your fleet and turning back for the rest of the battle.

This is mostly feasible if they know where you'll be (e.g. to attack a fleet known orbiting a planet or skimming for fuel) or they have a forward observer (either a undetected drone or some trojan horse ship) to tell where defending fleet is.

As I understand it, the ref - or perhaps the two players by agreement - set the initial encounter parameters. Your suggestion sounds viable assuming, as you say, you know about where the enemy fleet is without having to set "eyes" on them. The Zhodanis diving on Jewell comes to mind. However, two things:

First, if we assume a fleet engagement, then the defending fleet has many more sensors than your drone/trojan. Given a perimeter guard, your drone/trojan is very likely to be sensed and engaged by the outer perimeter before it can get close enough to get detection rolls in on the core fleet assets. If fast enough, it might survive the initial engagement and spot some fleet units, but it's unlikely to spot more than a fraction of the fleet before being destroyed - and they will respond by moving. ("Each new combat round, as long as the unit does not move out of its square, the sensor lock on stays in effect. If the unit moves one or more squares, a new sensor scan and lock on task must be performed;" MT Referee's Manual.)

Second, were I the second player about to sit down and play you, I would argue that the encounter STARTS from the first instant at which the attacking fleet enters potential detection range. Yes, you could conceivably start beyond that and close to point-blank range in a turn with enough built-up speed, but that sounds more like gaming the rules than playing a realistic scenario; I would resist the notion that the defending fleet doesn't even have a chance to know you're there until you're in the middle of them. It's a 20-minute turn involving ranges of 375 to 475 thousand kilometers, the fleet would have time to get a shot off - assuming they could detect you and pull off a lock at that range (roll of 12, doable but difficult). If they didn't make their rolls, well, THEN you'd be among them before they could react.

With the increased detection ranges, your scenario is still plausible: you start the game out at extreme range, dive immediately to near in the next round, then sweep out to extreme. Maybe. I have to expect the enemy fleet will respond to the drone probe by moving, if for no other reason than to spoil whatever sensor locks the drone achieved and hinder your tactical plans; they will CERTAINLY start moving after you show up at the edge of their detection range. You will respond to counter their movement, but at that point it becomes a question of who has the higher acceleration: they could still end up handing you range DM penalties if their acceleration were 3-g higher than yours, since those occur for anything above 2 range bands.

Your disadvantages are: there's no chance of surprise (the drone gave it away, they're expecting you next), and you'd still have to make detection and lock-on rolls for all enemy units, since the enemy fleet is unlikely to stay in the same square after a drone sailed through to give away their locations.

Now, if you DIDN'T use drones or a trojan, I'd say you were as vulnerable to surprise as the defender since you don't actually have eyes on his position: "He's GOT to be in orbit around Jewell, and there we'll ... what? He's not there??" A fast defending fleet could conceivably be anywhere within about a half light-second of the target planet - a rather large volume of space for your tactical planning - and still manage to get back to it in time to intercept you if you dove straight for the planet. In that scenario, you start 19 bands from the planet, wondering where the opposing fleet is while he hangs off 6 bands farther back, receiving intelligence on you from the planet's detection grid (assuming they have a base or are advanced enough to have effective sensors).

(Makes an interesting challenge for low-end smugglers. A destroyer escort with a Model 8-9 computer - or even a Kinunir with it's Model 7 - is going to spot the smuggler's scout/free trader long before that miscreant will see the DE. Even a Gazelle or a simple 50-ton fighter would have a distinct advantage - possibly to the extent of being able to fire from beyond the smuggler's detection range. The smuggler could speed for the planet but has to be slow enough for planetfall before he gets there. Very challenging.)

 

[Tobias]

Also means the Imperial 50-ton fighters, with their model 7-cum-6 computers two ranks below those of the typical TL-14 opponent, still have a slight edge against the battlewagons (16 vs 14). Does trash my initial thoughts about using 10-ton minis, though. Sigh.

In MegaTraveller, this is not an issue. You can easily fit a model 9 computer (3 model 9 computers as per the rules, since all spacecraft need double redundancy) into a 20 ton fighter. There are no rules for reducing the effective computer model due to lack of a bridge either. OTOH 10 ton fighters are not really possible under the MT rules since thruster plates do not work below 20 tons.

 

[McPerth]

As I understand it, the ref - or perhaps the two players by agreement - set the initial encounter parameters. Your suggestion sounds viable assuming, as you say, you know about where the enemy fleet is without having to set "eyes" on them. The Zhodanis diving on Jewell comes to mind. However, two things:

First, if we assume a fleet engagement, then the defending fleet has many more sensors than your drone/trojan. Given a perimeter guard, your drone/trojan is very likely to be sensed and engaged by the outer perimeter before it can get close enough to get detection rolls in on the core fleet assets. If fast enough, it might survive the initial engagement and spot some fleet units, but it's unlikely to spot more than a fraction of the fleet before being destroyed - and they will respond by moving. ("Each new combat round, as long as the unit does not move out of its square, the sensor lock on stays in effect. If the unit moves one or more squares, a new sensor scan and lock on task must be performed;" MT Referee's Manual.)

Second, were I the second player about to sit down and play you, I would argue that the encounter STARTS from the first instant at which the attacking fleet enters potential detection range. Yes, you could conceivably start beyond that and close to point-blank range in a turn with enough built-up speed, but that sounds more like gaming the rules than playing a realistic scenario; I would resist the notion that the defending fleet doesn't even have a chance to know you're there until you're in the middle of them. It's a 20-minute turn involving ranges of 375 to 475 thousand kilometers, the fleet would have time to get a shot off - assuming they could detect you and pull off a lock at that range (roll of 12, doable but difficult). If they didn't make their rolls, well, THEN you'd be among them before they could react.

With the increased detection ranges, your scenario is still plausible: you start the game out at extreme range, dive immediately to near in the next round, then sweep out to extreme. Maybe. I have to expect the enemy fleet will respond to the drone probe by moving, if for no other reason than to spoil whatever sensor locks the drone achieved and hinder your tactical plans; they will CERTAINLY start moving after you show up at the edge of their detection range. You will respond to counter their movement, but at that point it becomes a question of who has the higher acceleration: they could still end up handing you range DM penalties if their acceleration were 3-g higher than yours, since those occur for anything above 2 range bands.

Your disadvantages are: there's no chance of surprise (the drone gave it away, they're expecting you next), and you'd still have to make detection and lock-on rolls for all enemy units, since the enemy fleet is unlikely to stay in the same square after a drone sailed through to give away their locations.

Now, if you DIDN'T use drones or a trojan, I'd say you were as vulnerable to surprise as the defender since you don't actually have eyes on his position: "He's GOT to be in orbit around Jewell, and there we'll ... what? He's not there??" A fast defending fleet could conceivably be anywhere within about a half light-second of the target planet - a rather large volume of space for your tactical planning - and still manage to get back to it in time to intercept you if you dove straight for the planet. In that scenario, you start 19 bands from the planet, wondering where the opposing fleet is while he hangs off 6 bands farther back, receiving intelligence on you from the planet's detection grid (assuming they have a base or are advanced enough to have effective sensors).

I'm affraid we have quite different aproaches to the problem. As i understand you, you're assuming a 'wargame', so to say, a match as a TCS contest could be. I think on a battle in a true war, more as a TCS battle may be in a campaign.

When I talk about a trojan ship, I didn't mean a stealth ship. As you say, as much stealthy as it could be, it will be detected by a fleet and destroyed on sight if trying to avoid tehm, or at least warned and boarded if it acts suspiciously. I was talking about a free trader (with upgraded sensors) just merging on the civilian traffic, or parked in orbit while 'awaiting clearence' and informing the deffender's positions to the incoming fleet by thight beam.

Of course, the high speed incoming fleet, being in general quarters and with all weapons glearing, will have a high advantage over the defenders, that don't expect the attack. also of course, the battle will be a one round affair before the attacking fleet overpasses and it's lost in the distance (even if they try to decelerate, they're quite likely to be out of range in one round).

Even if there's no trojan or drone (or ground team, if the fleet is deffending a planet) to detect them, the fact that the incoming fleet is ready for battle and the deffenders aren't will give them a clear advantage for this term. The main point here is to close at enough speed as not to give the defenders time to ready themselves.

Of course, this plan is not possible in a TCS contest, where there are limits to the gaming space and no speed is buit in at the begining, but it's quite plausibe in a TCS campaign. I guess you were talking about a turney and I was about a war, so to say.

 

[Carlobrand]

In MegaTraveller, this is not an issue. You can easily fit a model 9 computer (3 model 9 computers as per the rules, since all spacecraft need double redundancy) into a 20 ton fighter. There are no rules for reducing the effective computer model due to lack of a bridge either...

Goodness, the Model 9 got shrunk! And the trio's taking only 0.03 Mw? It's hard to wrap my head around all these changes.

...OTOH 10 ton fighters are not really possible under the MT rules since thruster plates do not work below 20 tons.

I can see where the rules say that, but I'm trying to reconcile that with the 10-ton fighter featured in the Imperial Encyclopedia. Oh, wait: that puppy uses grav generators, it's a vehicle. Tricky! Sooo ... what happens if you drop the thing off in deep space? Do those 63g's (!!) of gravitic power get you anything there?

 

[Carlobrand]

...As i understand you, you're assuming a 'wargame', so to say, a match as a TCS contest could be. I think on a battle in a true war, more as a TCS battle may be in a campaign.

When I talk about a trojan ship, I didn't mean a stealth ship. ... I was talking about a free trader (with upgraded sensors) just merging on the civilian traffic, or parked in orbit while 'awaiting clearence' and informing the deffender's positions to the incoming fleet by thight beam.

Of course, the high speed incoming fleet, being in general quarters and with all weapons glearing, will have a high advantage over the defenders, that don't expect the attack. also of course, the battle will be a one round affair before the attacking fleet overpasses and it's lost in the distance (even if they try to decelerate, they're quite likely to be out of range in one round).

Even if there's no trojan or drone (or ground team, if the fleet is deffending a planet) to detect them, the fact that the incoming fleet is ready for battle and the deffenders aren't will give them a clear advantage for this term. The main point here is to close at enough speed as not to give the defenders time to ready themselves...

Hmmm ... No, you do not understand me. I'm thinking true war. I think you're just underestimating your enemy.

You're talking Pearl Harbor here - catching the enemy fleet flatfooted. Maybe in peacetime. I'm having trouble believing that a fleet in wartime, knowing that's possible, is not going to set Condition 3, sensors manned, screens on standby and ready, and power plant running hot enough at least to give me decent g's in the event of an attack. Perhaps a ship undergoing repairs would be at Condition 5, but the bulk of the fleet is at Condition 3 and ready. You might convince me they can't bring power to full quickly enough to fire the mesons and lasers and such on the turn you appear - although I can't find anything in canon to support that, so I think I'm being generous there. You're not going to convince me that trained military personnel in wartime, whose lives depend on their reactions and with all that tech available to them, don't have the sensors manned and can't get the men to battlestations, the ship moving, sandcasters ready, screens on and - assuming those sensor men can manage the lock roll - missiles launched within three to four minutes of you showing up on long-range sensors. And the ship should be fully combat-ready a turn after that - just when you expect to be at short range making your shots. If a ship can't manage that in wartime, space the XO. And that's not considering the pickets, patroling for early warning and ready for a fight.

You have a particular image in mind, but it's not conforming to rules or reality. You're not reckoning with the time involved. You're trying to force a surprise situation against trained military personnel who, in wartime, are aware of and expecting such tactics. You're expecting to cross 375 to 475 thousand kilometers - more if you're trying to bypass the pickets and hit the core of the fleet - in 20 minutes and not have your target alert and ready when you get to the end of it. There's nothing in the rules or in any realistic assessment of how people react that gives you 20 minutes free of charge.

No, when you hit the edge of his sensor range, his neutrino detectors and densitometers have the potential to start singing THEN - and if they do, he has a chance of reacting THEN. If his sensor detection rolls fail, well then, your scenario becomes possible. However, there's no argument whereby you can say the sensors stay quiet while you sail through the intervening hundreds of thousands of klicks to suddenly show up at his doorstep.

As to your scout-in-sheep's-clothing, that might work to some extent. Depends on the tech level, I think. As I pointed out, the fleet can "anchor" anywhere within a half light-second of a planet and get there within a turn. Your spyship is jumping in 100 radii from the planet - anything from 160 thousand klicks out to 1.6 million klicks out. (The small worlds are a security problem. Larger worlds are increasingly better for me as you start farther out.) From there, in wartime, you'd be guided through "traffic lanes", instructed to fly a specific course, specifically to keep possible spies from potentially gaining information about fleet strength and disposition. You're limited to passive sensors - chirp once and you're presumed hostile. Leave the traffic lane and you're presumed hostile. With even a single destroyer-escort monitoring the lane, hostile is not healthy for the spyship. I can arrange things so the planet blocks you until my port authority searches you. I can arrange things so civilian traffic does not threaten my fleet - except for the neutrino detector.

I can't stop the neutrino detector short of holding you for inspection when you first jump in at the 100-diameter mark. I might just do that if I'm an admiral close to the war zone: your little ship could as easily be a booby trap intended to smack into my groundside bases ala Broadsword. Your spy ship is not going to work at a world like Jewell or Regina at the height of the war, where they're expecting trouble with a capital T. Your high-speed fleet simply isn't going to get the sensor intelligence they need to come in "with all weapons glearing"; they're gonna have to make their own sensor detection and lock rolls before they shoot, just like me. However, inspecting civilians at the 100-diameter mark involves more boats and effort than simply letting them come in and inspecting them close to the planet - and civilian governments far from the warfront are likely to complain about that level of intrusion in traffic. Deep behind my lines, where I'm not expecting action, a raider working with a spy ship might just get lucky.

Still, between pickets at Condition 2 and my main fleet at condition 3, that luck will only go so far. Your fleet is not going to have the easy time you'd like - not unless every sensor operator in my fleet is asleep at the "wheel".

 

[Tobias]

Goodness, the Model 9 got shrunk! And the trio's taking only 0.03 Mw? It's hard to wrap my head around all these changes.

Yep, this happened so they could be fit into vehicles. Also, a computer consuming several gigawatts of electric power would have been a little bit silly, but being silly has not exactly stopped the rule designers in other places...

I can see where the rules say that, but I'm trying to reconcile that with the 10-ton fighter featured in the Imperial Encyclopedia.

First of all, this design (like many others) is severely broken. I haven't bothered to do the complete math, but just at first glance: The mass is clearly far too low (the fusion power plant alone would mass more than the entire fighter) and it has a total of 186 Mw of power but mounts a 250 Mw Beam Laser.

Oh, wait: that puppy uses grav generators, it's a vehicle. Tricky! Sooo ... what happens if you drop the thing off in deep space? Do those 63g's (!!) of gravitic power get you anything there?

The basic MegaTraveller rules don't really answer that question. The errata say that...

An anti-grav unit requires a gravity well to push against, so an anti-grav maneuver drive is less efficient at 10 diameters and beyond. The effective maneuver number of the craft drops by 50% at 10 diameters and beyond; for example, a maneuver-2 drive drops to a maneuver-1, and a maneuver-1 drops to a maneuver-0.5. Thruster units do not suffer these effects.

But this still doesn't cover really deep space. I'd argue that in such cases, the grav drive would effectively cease to function. Even the above interpretation is problematic: It essentially transforms every grav vehicle into a spacecraft.

 

[Hyphen]

I realise I'm quoting from memory, but I thought grav plates reduced to 10% efficiency in deep space. That would turn a 63G drive (where IS that, exactly??) into a 6G one.

 

[aramis]

I realise I'm quoting from memory, but I thought grav plates reduced to 10% efficiency in deep space. That would turn a yeG drive (where IS that, exactly??) into a 6G one.

It is in T4, not MT.

 

[Tobias]

I realise I'm quoting from memory, but I thought grav plates reduced to 10% efficiency in deep space. That would turn a 63G drive (where IS that, exactly??) into a 6G one.

The fighter in the imperial encyclopedia is listed with a thrust of 1173 tons and a mass of 18.7 tons, which would in fact yield a 63g acceleration. But as I said above: These values are wrong, and the whole design is severely broken. Here is a corrected version from the errata:

CraftID: Fighter, TL15, MCr19.63088
Hull: 9/23, Disp=10, Config=3AF, Armor=40G, Unloaded=179.7tons, Loaded=189.1tons
Power: 3/5, Fusion=627.5Mw, Duration=5/15
Loco: 3/5, StdGrav, Thrust=1773 tons, MaxAccel=9.4G (DeepSpace=4.7G), NOE=190kph,
Cruise=3150kph, Top=200kph, Agility=6
Commo: Radio=System
Sensors: PassiveEMS=Interplanetary, ActiveEMS=Planetary, ActObjScan=Diff, ActObjPin=Diff, PasEngScan=Rout
Off: BeamLaser = xx2
Batt xx1
Bear xx1
Def: DefDM=+10
Control: Computer=2×3, Panel=HoloLink, Special=HoloHUD×1/2/2, Env=basic env, basic ls, ext ls, grav plts, inertial comp.
Accomm: Crew=1 (Operator =1), Seats=Roomy×1
Other: Cargo=6.75kl, Fuel=37.65kl; ObjSize=Avg, EmLevel=Mod

 

[Carlobrand]

I see however that there's a 20-ton TL15 fighter in Fighting Ships of the Shattered Imperium, model-9 computers and a good sensor suite, that would do quite nicely in the picket role.

 

[E.D.Quibell]

It is in T4, not MT.

It is. It's in the TL descriptors in the Referees Source Book page 33.

Best regards,

Ewan

 

[aramis]

It is. It's in the TL descriptors in the Referees Source Book page 33.

Best regards,

Ewan

There is no "Referee's Source Book"
The Referee's Manual, page 33, is in the animals chapter.
The Referee's Companion, page 33 doesn't list the radii at all.

Tech Level 9 (circa 2070): Suborbital shuttle aircraft become common, allowing speeds of more than 10,000 kph. Late in the period, the gravitic vehicle is developed, although at this point such vehicles are only capable of altitudes of less than 10 meters
Tech Level 10: (circa 2700): Gravitic vehicles are now capable of altitudes of several hundred meters, and thus qualify marginally as aircraft.
Tech Level 11: Gravitic vehicles blend the various transportation technologies (air, land, and water) into a single technology.​

and

Tech Level 10 (circa 2100): The availability of Jumpe drive makes interstellar travel common during this period. Gravitic maneuver drives replace older chemical thrust maneuver drives. However, gravitic maneuver drives have difficulty operating away from large masses (they need the strong gravity field to push against).
Tech Level 11: Jump2 drive is invented. Research into the problems of gravitic drives leads to the introduction of thruster technology. Thruster technology, a combined spin-off of gravitic and damper technology, uses a strong molecular repelling force to produce reactionless thrusters which push against large plates mounted on the space vessel. Thrusters do not require the presence of a large gravity field to operate effectively, but instead are highly localized with virtually none of the projection ability of gravitics.​

Ref's Companion pages 33-34

No "10 diameter limit" and no 10% efficiency. It wasn't until T4 that we got a positive definition of the limit for gravitics and the effects of crossing it.

 

[mike wightman]

IIRC these numbers were first presented in a DGP MT Journal - but I could be remembering wrong and my books aren't immediately to hand.

It could be in the Q&A section. When I'm home I can check.

 

[McPerth]

Hmmm ... No, you do not understand me. I'm thinking true war. I think you're just underestimating your enemy.

You're talking Pearl Harbor here - catching the enemy fleet flatfooted. Maybe in peacetime. I'm having trouble believing that a fleet in wartime, knowing that's possible, is not going to set Condition 3, sensors manned, screens on standby and ready, and power plant running hot enough at least to give me decent g's in the event of an attack. Perhaps a ship undergoing repairs would be at Condition 5, but the bulk of the fleet is at Condition 3 and ready. You might convince me they can't bring power to full quickly enough to fire the mesons and lasers and such on the turn you appear - although I can't find anything in canon to support that, so I think I'm being generous there. You're not going to convince me that trained military personnel in wartime, whose lives depend on their reactions and with all that tech available to them, don't have the sensors manned and can't get the men to battlestations, the ship moving, sandcasters ready, screens on and - assuming those sensor men can manage the lock roll - missiles launched within three to four minutes of you showing up on long-range sensors. And the ship should be fully combat-ready a turn after that - just when you expect to be at short range making your shots. If a ship can't manage that in wartime, space the XO. And that's not considering the pickets, patroling for early warning and ready for a fight.

You have a particular image in mind, but it's not conforming to rules or reality. You're not reckoning with the time involved. You're trying to force a surprise situation against trained military personnel who, in wartime, are aware of and expecting such tactics. You're expecting to cross 375 to 475 thousand kilometers - more if you're trying to bypass the pickets and hit the core of the fleet - in 20 minutes and not have your target alert and ready when you get to the end of it. There's nothing in the rules or in any realistic assessment of how people react that gives you 20 minutes free of charge.

No, when you hit the edge of his sensor range, his neutrino detectors and densitometers have the potential to start singing THEN - and if they do, he has a chance of reacting THEN. If his sensor detection rolls fail, well then, your scenario becomes possible. However, there's no argument whereby you can say the sensors stay quiet while you sail through the intervening hundreds of thousands of klicks to suddenly show up at his doorstep.

As to your scout-in-sheep's-clothing, that might work to some extent. Depends on the tech level, I think. As I pointed out, the fleet can "anchor" anywhere within a half light-second of a planet and get there within a turn. Your spyship is jumping in 100 radii from the planet - anything from 160 thousand klicks out to 1.6 million klicks out. (The small worlds are a security problem. Larger worlds are increasingly better for me as you start farther out.) From there, in wartime, you'd be guided through "traffic lanes", instructed to fly a specific course, specifically to keep possible spies from potentially gaining information about fleet strength and disposition. You're limited to passive sensors - chirp once and you're presumed hostile. Leave the traffic lane and you're presumed hostile. With even a single destroyer-escort monitoring the lane, hostile is not healthy for the spyship. I can arrange things so the planet blocks you until my port authority searches you. I can arrange things so civilian traffic does not threaten my fleet - except for the neutrino detector.

I can't stop the neutrino detector short of holding you for inspection when you first jump in at the 100-diameter mark. I might just do that if I'm an admiral close to the war zone: your little ship could as easily be a booby trap intended to smack into my groundside bases ala Broadsword. Your spy ship is not going to work at a world like Jewell or Regina at the height of the war, where they're expecting trouble with a capital T. Your high-speed fleet simply isn't going to get the sensor intelligence they need to come in "with all weapons glearing"; they're gonna have to make their own sensor detection and lock rolls before they shoot, just like me. However, inspecting civilians at the 100-diameter mark involves more boats and effort than simply letting them come in and inspecting them close to the planet - and civilian governments far from the warfront are likely to complain about that level of intrusion in traffic. Deep behind my lines, where I'm not expecting action, a raider working with a spy ship might just get lucky.

Still, between pickets at Condition 2 and my main fleet at condition 3, that luck will only go so far. Your fleet is not going to have the easy time you'd like - not unless every sensor operator in my fleet is asleep at the "wheel".

I don't see as impossible to make such a surprise attack, if you take into consideration the enormous speeds those fleets may reach. of course the main problem will be to detect/lock on the defending fleet, so I talked about this trojan horse free trader (wich won't make the lock on, as you say, unless quite tight coordination may be achieved, but at least may make a pasive scan and ell the incoming fleet about number and aproximate location of the defending fleet). them more civilian traffic is in the world, the easier for this trojan reccon to work (just do the pasive, probably neutrino, scan and tell the fleet by tight beam).

The incoming fleet, if after a full day of 6 G aceleration, will come at a speed about 432 relative, so, asuming your maximum detection range of 20 squares, will close in less than 1/20 of a turn (so less than a minute of warning). I guess even a conditon 2-3 fleet (I assume those are quite high readiness status, I don't know exactly what they mean) will have no time to be fully manned in less than a minute.

After this initial atack (and only one shoot), the attacking fleet will be out of detection range in less than another minute, probably not even knowing the damage they've done to the defender fleet.

And yes, it will only work for Pearl Harbour (or more likely Tarento, as fleet is already on war footing) style raids looking only for fleet damage, not for full invasions or more decisive battles.

 

[Carlobrand]

I don't see as impossible to make such a surprise attack, if you take into consideration the enormous speeds those fleets may reach. ...

The incoming fleet, if after a full day of 6 G aceleration, will come at a speed about 432 relative, so, asuming your maximum detection range of 20 squares, will close in less than 1/20 of a turn (so less than a minute of warning). I guess even a conditon 2-3 fleet (I assume those are quite high readiness status, I don't know exactly what they mean) will have no time to be fully manned in less than a minute.

After this initial atack (and only one shoot), the attacking fleet will be out of detection range in less than another minute, probably not even knowing the damage they've done to the defender fleet.

And yes, it will only work for Pearl Harbour (or more likely Tarento, as fleet is already on war footing) style raids looking only for fleet damage, not for full invasions or more decisive battles.

Yes, I can see you don't see it as impossible. You're quite wedded to the idea. My counter is simple: if it's at all possible, someone's going to be putting a great deal of thought and effort into keeping it from happening, if for no other reason than to preserve his forces.

So, you're not going to catch a fleet on war footing that way short of just flat getting lucky. Civilians will be stopped well away from the fleet, searched, and guided in where there's a chance that a "civilian" could be a spy for a potential attacker. The friendly fleet will be kept moving. I'll have pickets well out - maximum detection's 20 squares out from THEM, and if I'm guarding a planet, they're likely to be out near the jump point to monitor for anything jumping in. And if a half-light-second range is inadequate, I can have them sit back a second and a half away from the planet, widening the range enough that your randomly diving fleet has a 50:50 chance of shooting through without catching my fleet in your sensor range, while I remain close enough to get back to the planet and challenge anyone approaching more conservatively - after all, you're not about to enter low orbit and bombard if you're travelling at 0.03C.

Your best shot is actually at the screening fighters; as you point out, they'll have about a minute between the time you show up and the time you're among them - but that's ample time to hit the "gas pedal" and evade, and they're intended to be expendable. The rest of the fleet will be well back from that, you don't know where exactly, and I'll be doing my level best to keep that information from you until your fleet commits to battle.

The most likely outcome is you will flash through, possibly chew up a few fighters, and then spot the enemy fleet only to find yourself unable to adjust course enough on your pass to come close enough for anything but missiles. If you're LUCKY, you might manage a path that, with that single turn's course adjustment, gives your mesons a chance to hit. However, that fleet WILL have screens up and be evading and, yes, firing missiles back at you. If you, in the short time you have on detecting the main fleet, can achieve sensor locks and then fire weapons in under a minute while zipping past, then I, given slightly more time thanks to the fighters' sacrifice, and with men already at the sensors, can do the same for at least my missiles. The BEST you can hope for is that I won't be able to use my power-consuming weapons.

 

[McPerth]

Yes, I can see you don't see it as impossible. You're quite wedded to the idea. My counter is simple: if it's at all possible, someone's going to be putting a great deal of thought and effort into keeping it from happening, if for no other reason than to preserve his forces.

I only say the rules could allow it, and sure, much effort will be dedicated to avoid this kind of raid (just as much was dedicated to avoid new raids as Pearl Harbour or Tarento.

So, you're not going to catch a fleet on war footing that way short of just flat getting lucky. Civilians will be stopped well away from the fleet, searched, and guided in where there's a chance that a "civilian" could be a spy for a potential attacker. The friendly fleet will be kept moving. I'll have pickets well out - maximum detection's 20 squares out from THEM, and if I'm guarding a planet, they're likely to be out near the jump point to monitor for anything jumping in. And if a half-light-second range is inadequate, I can have them sit back a second and a half away from the planet, widening the range enough that your randomly diving fleet has a 50:50 chance of shooting through without catching my fleet in your sensor range, while I remain close enough to get back to the planet and challenge anyone approaching more conservatively

I guess those measures would be taken. I don't believe you can so stop all civilian traffic as you say, at least in HiPop planets, more so if they have no biosphere and need to import the most basic supplies (say Glisten), but you can take the other measures you say.

The measure that I don't see as possible is to watch the jump point to monitor anything jumping it, as Traveller, AFAIK, has no fixed jump points. neither to exit the system nor to jumping in system. THe only limit I can recall is that you cannot jump inside the 100 diameter limit, but, aside from that, you can jump anywhere in the system, incluiding in the middle of nothing (let's say, half point among two planets).

- after all, you're not about to enter low orbit and bombard if you're travelling at 0.03C.

While I agree with you, MT rules, as written, don't. This has just been discussed in another thread:

Actually, yes, it does do a non-accumulated vector.

Movement: Movement speed is specified based on the unit’s maneuver drive value. For example, a unit with a maneuver drive of 1 can start out from a standing start with a movement speed of 1 for the turn. The unit can move a maximum of one square at movement speed 1.
Each unit must specify a movement speed to be used for the turn. The movement speed represents the maximum number of squares the unit can move that turn; however, the unit may move any number of squares less than the maximum, or it may even remain stationary (25,000 km per square is a lot of space-in effect, the unit is circling in the square).
A unit may change speed each combat round by up to its maneuver drive value. Thus if a unit with a maneuver drive-6 is moving at speed 10, the next time it takes a turn, it may reduce its speed to as low as speed 4, or it may increase its speed to as high as speed 16 or any value in between. Or it may leave its speed unchanged at 10​

Page 92, left column. Emphasis mine, italics original.

As you see, as the rules are written, you can come at 0.03 C and stop in orbit of the planet to bombard it (while mantaining your speed, that you can decelerate at most as your G rating allows ). You can read my opinion about that on the thread where this was discusses (and from where the above quate is taken, so you'll find it easily).

Your best shot is actually at the screening fighters; as you point out, they'll have about a minute between the time you show up and the time you're among them - but that's ample time to hit the "gas pedal" and evade, and they're intended to be expendable. The rest of the fleet will be well back from that, you don't know where exactly, and I'll be doing my level best to keep that information from you until your fleet commits to battle.

Aside that I'd rather use drones than fighters, I agree. I guess in wartime, and near the bases, sensor drones are deployed along nearly all the system, being used in high quantities (more or less like sonobuoys are used today in ASW).

The most likely outcome is you will flash through, possibly chew up a few fighters, and then spot the enemy fleet only to find yourself unable to adjust course enough on your pass to come close enough for anything but missiles. If you're LUCKY, you might manage a path that, with that single turn's course adjustment, gives your mesons a chance to hit. However, that fleet WILL have screens up and be evading and, yes, firing missiles back at you. If you, in the short time you have on detecting the main fleet, can achieve sensor locks and then fire weapons in under a minute while zipping past, then I, given slightly more time thanks to the fighters' sacrifice, and with men already at the sensors, can do the same for at least my missiles. The BEST you can hope for is that I won't be able to use my power-consuming weapons.

Well, if I can avoid your power consuming weapons while using mine against your fleet, I'll have a big advantage as to crippling ships.

Anyway, I don't say it would be easy, and, if at all possible, only under very determinate circumstances. This would be (as you said) like Pearl Harbour or Tarento, or like the fireship use in the age of sail, something that could be tried from time to time, if circumstances allow, to attain limited results. I agree with you that you could not base your strategy on this kind of raids.

 

[aramis]

I'll note that I don't use any of the Space Combat chapter of MT in play. Rejected it the moment I first read it...

 

[Carlobrand]

Can't blame you for that, Aramis; the thing's giving me headaches.

... I don't believe you can so stop all civilian traffic as you say, at least in HiPop planets, more so if they have no biosphere and need to import the most basic supplies (say Glisten) ...

I'm not seeing why stop-and-inspect is an issue. This isn't the Houston Ship Channel; this is open space. I've got a volume of hundreds of thousands of square miles to work with, so stacking them up isn't an issue. I'm protecting fleets involving squadrons of cruisers or dreadnoughts - there are more than enough boats and personnel available to board and inspect everyone without them have to "wait in line" for it. And, if it's in a war zone, I'm not likely to get much grief from the locals. Maybe at Mora, but I can't see the folks on, say, Vilis or Regina objecting to it.

...The measure that I don't see as possible is to watch the jump point to monitor anything jumping it, as Traveller, AFAIK, has no fixed jump points. ...

No, the "jump point" is not a fixed point; it's a spherical shell defined by a radius of 100 planetary diameters; you can go anywhere you want outside of that, but you have to cross that shell eventually if you want to go to Planet X. Things show up on sensors near that shell, I tell them to stop for inspection, I shoot them if they repeatedly ignore my orders. They want to try to dash in, I shoot them on general principals. There's a war on, you're in a war zone, I've already put the wartime navigation rules out on Tri-V, extreme stupidity has always carried the death penalty, and a fighter's sensors and missiles work just dandy against merchants as far as a light-second or two away. Any officer who feels like they need to risk a dreadnought to pacify the captain of a free trader can spend the rest of his career wearing stripes in a prison barge.

Glisten is another issue - the primary "world" is an asteroid belt. On the one hand, I can't defend it with organized inspections at the jump point because ships are accustomed to jumping right to the place - or close enough as makes no difference from my fleet's perspective. I'd have to come up with alternate defensive plans. On the other hand, if you want to try going 0.03c in an asteroid belt, be my guest - but I hope you have a very good map, 'cause a rock the size of a baseball at those speeds is hitting with the force of a nuclear warhead. (KE=1/2MV^2; v=at=60m/s^2*86400s=5,184,000m/s; KE=1/2m(5184000)^2=m*1.344*10^13 joules, or energy equivalent to a 3kt explosion per kilogram.)

Which brings up a number of interesting questions:
1. CAN you do 0.03c when something as small as a grain of sand hits you like a ton of TNT? WILL it hit you like a ton of TNT, or will it become a grain-sized bit of million-degree plasma that drills through your ship like a hot needle through wax, taking most of its energy with it when it exits at the other end - and what is the impact of that on ship and crew? I don't know how many grain-sized meteors there are in any given volume of space, but it occurs to me that you're going to find out, having flown through some 224 million kilometers of space to get here and with another 224 million before you stop. Running into something bigger is likely to hurt.
2. How do missiles work at those speeds? That momentum confers enormous energy: the warheads are vaporized before they can detonate, but the impact alone carries as much energy as a nuke. However, would they even have a chance at penetrating sandcasters, or would sand hitting like 1-ton bombs shatter the missiles enough that the target would escape damage. Or would a sand grain superheated to million-degree plasma by such an impact simply drill through the missile like the aforementioned hot needle through wax? Would the missile likewise drill through the target ship like a needle through wax rather than apply that energy explosively? (Would we do better firing sandcasters at each other?)
3. Can the missiles even function at that speed, or is the small amount of doppler shift at that speed enough to confuse their targeting systems. Are their computer-brains able to calculate intercept angles for such velocities?

...As you see, as the rules are written, you can come at 0.03 C and stop in orbit of the planet to bombard it ...

The example given contradicts the rule given.

"A unit may change speed each combat round by up to its maneuver drive value. Thus if a unit with a maneuver drive-6 is moving at speed 10, the next time it takes a turn, it may reduce its speed to as low as speed 4, or it may increase its speed to as high as speed 16 or any value in between. Or it may leave its speed unchanged at 10."

That seems to indicate that deceleration is limited to maximum g's as well. Ergo, the rule is poorly worded and the clarifying example guides play.

No, you are not bombarding at those speeds. I don't see your missiles doing anything but vaporizing before they hit ground; you'd need something specifically designed to survive hitting atmosphere at those speeds, and then there's the problem of aiming. Fifth Frontier War - the only example of ground bombardment I know of - has a ship coming in to about 3000 Km to do it (specifically: you are placed on the map over your target, and planetary defenses can only fire on you at full strength if they're within 3 hexes of that spot - about 3000 km. - while they fire at half strength at targets in "close orbit", ergo you're very roughly in the vicinity of 3000 km from target.) You've got about a half-second to aim your directed-energy weapons and specially designed missiles as you flash past; I don't see you persuading an opposing player that you can do that. Also, you've confined your route to the point where there's a good chance the opposing fleet is out of your sensor range as you flash past, and a very, very good chance you're going to smack into orbiting trash while you're trying it. Best to pick one mission and stick to it.

Well, if I can avoid your power consuming weapons while using mine against your fleet, I'll have a big advantage as to crippling ships.

Don't overestimate your firepower. All other things equal, a T-meson has about a 6 in 36 chance of hitting a high-agility dreadnought-size ship beyond 50,000 km range - and it's not like a missile or a particle beam: with closing speeds measuring in meters per microsecond, I'm not confident your systems can time the thing well enough to ensure it goes off inside the target, not when the original design called for firing on targets at speeds measured in meters per second. It might not be an eligible weapon for this kind of scenario. (Unlike GDW, I don't believe in sitting there and waiting for the meson beam to blow me up. Agility is life at TL15.) Missiles have a 3/36 chance - assuming we don't rule they're automatically killed by sandcasters at those speeds.

You're hitting speeds the rules don't allow for. If your focus is the game, expect to have to do a lot of debating before you and your opponent settle on what's "real" at those speeds. If you're focus is realism, consider the potential ramifications of hypervelocity in both directions. Assuming it's not going to kill you (big assumption), the plan makes for an interesting scenario, with a few limits and provisos. Among them:

1. Mesons aren't going to work.
2. I think sand is ineffective - it will certainly kill the missile, but at such a close range that the missile's mass and momentum remain a lethal threat.
3. Nuclear dampers are ineffective - killing the warhead doesn't stop the danger.
4. Warheads are irrelevant. Taking a warhead from intact to "flat" in a couple hundred nanoseconds does not leave time for explosives to go boom in any organized way, and a few tens of kilograms of explosion in amongst a kiloton-level impact aren't going to get noticed. The missile becomes hypervelocity superheated plasma on impact, too quickly for the warhead to detonate. Treat all missiles as nukes, but with no radiation damage.
5. Particle beams, lasers, and energy guns remain effective, and lasers remain effective as a defense against missiles (250 Mw will cut through 7 meters of steel: the missile's mostly vapor).
6. We'd need to agree on some random way of determining where my fleet was when you made your pass.
7. There might be some risk from space objects - you're going at speeds that might make it a bit tricky to spot and dodge a random meteor in time.

That's a rough guess, but it should make for an interestingly unusual engagement.