• Welcome to the new COTI server. We've moved the Citizens to a new server. Please let us know in the COTI Website issue forum if you find any problems.
  • We, the systems administration staff, apologize for this unexpected outage of the boards. We have resolved the root cause of the problem and there should be no further disruptions.

Why is acceleration limited to 6g?

add: I've never liked the Queen Mary comparison. [...] I'm thinking the dreadnought is still one heck of a lot more maneuverable than the Queen Mary - and possibly the rowboat, given that it was fighting water too.

You're probably right, but there comes a point when you say "some decisions were made for game balance" - that is, to make the game playble & fun for the players - which can make post-design justifications seem a little thin.

;)
 
Certainly a fighter could manage the same faster, but I'm thinking the dreadnought is still one heck of a lot more maneuverable than the Queen Mary - and possibly the rowboat, given that it was fighting water too.

Here we should define what do we understand as maneuverable. If you mean to turn you ship 180º, so going backwards, you're probably right. If you mean turning your course 180º, so reversing your course, or to make an emergency stop when at maximum speed (as much as this term may be used in vaccum) I disagree.

One of the things that makes Traveller space combat 'unrealistic', IMHO is that we mostly assume a static (relative) start when combat begins. If (to put an example) we detect an enemy fleet in Jupiter and send our battleships from Earth at maximum acceleration to meet them, while they also accelerate to reach Earth ASAP (counting on arriving to Earth at a 0 relative speed), when the fleets meet at half point, their relative speeds will be tremendous, and they will at most shooting once against each other before being out of range again, having overpassed each other.

If you calculate to meet your enemy aproaching at a zero speed (relative to Sol), but the enemy keeps accelerating to reach earth ASAP, the relative speeds will keep being enormous (while only about half than in the first case), and the engagement will keep being a one shoot affair.

Also, if you are decelerating when you meet the other fleet, you must have your ship show you stern to the enemy in order to fully decelerate, so making your spinals useless (they're assumed to fire only forward) until they have overpassed you.

By applying the MT rules, as Aramis cite, you may have your fleet having been acelerating for a full day at 6 g (so with a speed of about 432 squares/turn) to remain static to keep shooting at your fleet (so making a deceleration equivalent to 432 G!!) while still keeping your bow towards your enemy, so being able to fire your spinal. (So assuming your thrust forward being, as said, about 10% of your thrust capability, your ship is capable to overload your 6 G drives up to about 4320 G). Surprised I think those rules are somewhat faulty?
 
Retourning to the main thread issue:

My personal in-game "why" is that grav "thruster" plates, which are effectively warp drives that twist space to propel the ship, can't warp space more than 6g worth without tearing space.

I agree with this explanation. Thruster plates efectively push your ship against nothing to obtain the acceleration, and I can accept without any more problem than the whole thruster principle that it has limits about how much can they push it.

Of course *chemical* thrusters or other reaction drives can go faster than that, but the convenience of reactionless gravitic drives keeps them the dominant form of propulsion.

Being mostly a MT player, IIRC in One Small Steep (HT and challenge), where reaction drives were defined, your final acceleration capability was given simply by thrust/mass, with no limit above what thrust can you achieve with what mass. And (IIRC again, as I don't have my HT handy now), with fusion drives you could attain 195 tons of thrust per 4 ton module of drive, so, once fuel, controls, hull, etc. were added, you could attain acceleration greater than 6 G.
 
Last edited:
Reread the bolded text... You NEVER have to move on your movement. It's a magic drive from hell.


Quite true, sadly.

I remember an "answer" addressing this problem written by one of the DGP bigwigs in one their Q&A columns suggesting that ships which chose not to "move" are simply zipping around in circles within a particular square.

When I read was when I mostly gave up on DGP...
 
Quite true, sadly.

I remember an "answer" addressing this problem written by one of the DGP bigwigs in one their Q&A columns suggesting that ships which chose not to "move" are simply zipping around in circles within a particular square. ...
Ouch. :oo:
 
One of the things that makes Traveller space combat 'unrealistic', IMHO is that we mostly assume a static (relative) start when combat begins.


No. In HG2, one of only two Traveller wargames designed to handle large numbers of large ships, combatants are relatively static with regards to each other. Nothing is stated regarding their vectors with regards to the objects with the star system they're fighting in.

If (to put an example) we detect an enemy fleet in Jupiter and send our battleships from Earth at maximum acceleration to meet them, while they also accelerate to reach Earth ASAP (counting on arriving to Earth at a 0 relative speed), when the fleets meet at half point, their relative speeds will be tremendous, and they will at most shooting once against each other before being out of range again, having overpassed each other.

Your examples merely explain why no competent fleet commander will send his force thrusting off from Earth orbit to reach Jupiter in an attempt to catch a force which is thrusting off from Jupiter orbit to reach Earth. The fictional fleet commanders in the game are not stupid enough to make that mistake because the people who invented the game are not stupid to make that mistake.

Historically, naval engagements have occurred in the deep oceans only a handful of times. Navies fight when they intercept each other and navies can only plan on intercepting each other around objectives. If you're defending Earth, you don't send your fleet off on some idiotic goose chase to Jupiter just because your enemy may have appeared there. You make your enemy come to you, you wait for them to come to their objective.

Vector movement means Traveller ship combat somewhat resembles a certain aspect of Age of Sail ship combat: That fleets only fight when both choose to do so. Yes, ships and formations can be "pinned", "trapped", or otherwise forced into combat in certain situations but for the most part ships and formations only fight when the choose to do so.
 
No. In HG2, one of only two Traveller wargames designed to handle large numbers of large ships, combatants are relatively static with regards to each other. Nothing is stated regarding their vectors with regards to the objects with the star system they're fighting in.

Yes, HG2 was too abstract, and movement was not featured in its combat system.


Your examples merely explain why no competent fleet commander will send his force thrusting off from Earth orbit to reach Jupiter in an attempt to catch a force which is thrusting off from Jupiter orbit to reach Earth. The fictional fleet commanders in the game are not stupid enough to make that mistake because the people who invented the game are not stupid to make that mistake.

Historically, naval engagements have occurred in the deep oceans only a handful of times. Navies fight when they intercept each other and navies can only plan on intercepting each other around objectives. If you're defending Earth, you don't send your fleet off on some idiotic goose chase to Jupiter just because your enemy may have appeared there. You make your enemy come to you, you wait for them to come to their objective.

Vector movement means Traveller ship combat somewhat resembles a certain aspect of Age of Sail ship combat: That fleets only fight when both choose to do so. Yes, ships and formations can be "pinned", "trapped", or otherwise forced into combat in certain situations but for the most part ships and formations only fight when the choose to do so.

Sure you will leave enemy fleet to come for you, but that also means that you must risk your planet to be attacked, as you either try to intercept enemy fleet midway to protect you base from harm, giving the scenario I put before, or wait for him to reduce velocity to manageable levels, but risk your base to harm.

In age of sail, battles were usually fougth far enough from your base to keep it out of reach, and in most historical naval engagements, fleets have sortied to engage enemy while the base was still secure from enemy ships (while perhaps not from enemy ship carried airplanes, when they exist).

And precisely those very high speeds and the inability to effectively intercept your enemy while at a secure distance from your base is (IMHO) what makes Traveller space combat not comparable to any combat we've seen historically.
 
I remember an "answer" addressing this problem written by one of the DGP bigwigs in one their Q&A columns suggesting that ships which chose not to "move" are simply zipping around in circles within a particular square.

And have ever those DGP bigwigs heard about momentum or only knew about raw speed? have they ever played Mayday (several years older, yet more credible in that sense)?

Frankly, while MT was my favorite Traveller version, that was not precisely because its space combat rules...
 
And have ever those DGP bigwigs heard about momentum or only knew about raw speed? have they ever played Mayday (several years older, yet more credible in that sense)?

Frankly, while MT was my favorite Traveller version, that was not precisely because its space combat rules...

I don't ever use the MT space combat rules. I instead use mayday movement and the vehicle combat rules from Ref's Companion...
 
Yes, HG2 was too abstract, and movement was not featured in its combat system.


Just because movement is abstracted in HG2 it doesn't mean that the situation being modeled in HG2 doesn't involve movement.

Sure you will leave enemy fleet to come for you, but that also means that you must risk your planet to be attacked...

Have you any conception of just how big a planet is?

... as you either try to intercept enemy fleet midway to protect you base from harm...

As has already been explained by both of us, only a moron will attempt a "midway" intercept.

... giving the scenario I put before, or wait for him to reduce velocity to manageable levels, but risk your base to harm.

Protip: War involves risk.

In age of sail, battles were usually fougth far enough from your base to keep it out of reach..

Utter horseshit. Seeing as interception during the Age of Sail relied on catching the enemy near an objective, most multi-ship actions were fought rather close to bases.

... and in most historical naval engagements, fleets have sortied to engage enemy while the base was still secure from enemy ships (while perhaps not from enemy ship carried airplanes, when they exist).

And those bases were normally secured by assets other than the ships based there. Age of Sail bases had shore fortifications, the Age of Dreadnoughts added minefields and coastal subs, and the Age of Aircraft added land based planes. Fleets are only one part of a base's defense and, seeing as the base must still be defended when the fleet is away, there will be a defense other than that provided by the fleet.

And precisely those very high speeds and the inability to effectively intercept your enemy while at a secure distance from your base is (IMHO) what makes Traveller space combat not comparable to any combat we've seen historically.

The last part of that sentence is the most accurate part of your post.
 
Just because movement is abstracted in HG2 it doesn't mean that the situation being modeled in HG2 doesn't involve movement.

Sure, but it is totally abstracted, and no relative speeds, nor positions are featured, only frontline and reserve, and your acceleration capability only applies as limit for your agility. In HG, if your 6 G agility 3 ship tries to breack off from a 4 G agility 4 ship, it will catch you, even while you can have higher linial acceleration to disengage.

Have you any conception of just how big a planet is?

I guess I have, at least for the planet I live on. Anyway, I guess if you have a fleet to defend it, though is because you want to minimize the damage the planet (and its facilities, either orbital or downside) receives.

As has already been explained by both of us, only a moron will attempt a "midway" intercept.

Then change "midway" by "far enough from the base to keep it secure".

Protip: War involves risk.

Sure, and a good commander is the one that minimizes it while achieving the best results.

Utter horseshit. Seeing as interception during the Age of Sail relied on catching the enemy near an objective, most multi-ship actions were fought rather close to bases.

Yes, rather close, but out of range for the weapons used. As I said above, the objective of your defending fleet is precisely to defend the base from harm (aside that doing as much damage as possible to the enemy).

And those bases were normally secured by assets other than the ships based there. Age of Sail bases had shore fortifications, the Age of Dreadnoughts added minefields and coastal subs, and the Age of Aircraft added land based planes. Fleets are only one part of a base's defense and, seeing as the base must still be defended when the fleet is away, there will be a defense other than that provided by the fleet.

And how many times have those defenses emerged victorious against a determined attacking fleet?

What has historically defended a base is the fleet there based (or in support), the defenses you say are as a last ditch measure, and rarely enough for its mision, once the attacking fleet has taken its decision to attack.

The last part of that sentence is the most accurate part of your post.

Glad to see we agree in something ;)
 
IIRC in some Q&A on a TD (or somewhere similar) it was specified that acceleration and agility were not seen as fully related in MT. They even put the example of comparing the Queen Mary with a rowboat. The Queen Mary will surely have more acceleration capability, but it will also be less maneuverable.

Agility was defined in MT as the ability to quickly change direction, not as the ability to accelerate more. That was the acceleration given to you by maneuver drives. So, I don't see the point to use agility as additional thrust.

add: I've never liked the Queen Mary comparison. As I recall, Queen Mary had to maneuver in a liquid water medium - a substance very unlike vacuum. A dreadnought in space, on the other hand, can pirouette in place like a giant ballerina, something the Queen has never managed. Limiting factor on the agility of the dreadnought is going to be how fast it can turn and point its drives in the direction it wants - which will in turn be governed by the 6G limit, i.e. the ability of the compensators to counteract centripetal acceleration on the end-points delivered by the rate of turn. Certainly a fighter could manage the same faster, but I'm thinking the dreadnought is still one heck of a lot more maneuverable than the Queen Mary - and possibly the rowboat, given that it was fighting water too.

The problem here is that, in space, speed and acceleration are less related than they are in an atmosphere.
A rowboat can stop, start and change direction easily because both its acceleration and its speed are low. However, in space, the large and small vessels are both capable of huge speeds, which need to be negated by acceleration in order to stop or radically change direction. Therefore in space, agility and acceleration are more closely linked.
 
Actually, yes, it does do a non-accumulated vector.

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

Since a turn is 20 minutes (1,200 seconds) and a square is 25,000 km, the speed of light is 14,400 squares per turn. Therefore a ship with 6 g's of acceleration can reach the speed of light in 33.333 days [14,400/6 = 2400 turns, 2400 x 20 minutes = 800 hours = 33.333 days] without actually moving at all. As written a 6g ship could just sit next to a planet for 5 weeks 'accelerating' to light-speed in place the whole time. The rules don't say they can't be refueled while 'accelerating'.

When anything dangerous comes up they just take their whole move and they'll be 20 light minutes [2.4 AU] away in one turn. At that point they can stop instantly. Anyone need to get to Mars in 20 minutes? In fact the rules don't even say that ships are limited by the speed of light. [1] Suppose that the ship just kept 'accelerating' in place for a few years....

Other than common sense and the annual maintenance rules I don't see why a ship couldn't keep accelerating in place for centuries, receiving refueling and crew changes along the way. If our 'ship' is actually a Highport capable of performing annual maintenance than maybe it could just perform annual maintenance on itself and then it could 'accelerate' in place forever?

Suppose Cleon had ordered a 6G ship to accelerate in place. Eleven hundred years later the ship would have a normal space velocity of over 12,000 C, or about 232 LY a week. And now we know just how the Imperiums ultimate secret fast courier network really works [Grins, ducks, runs.]

[1] Ignoring a few minor details like the laws of physics, the mass of the ship increasing exponentially to that of the whole universe, the radiation killing the crew and ship, and other such petty details.
 
Last edited by a moderator:
Since a turn is 20 minutes (1,200 seconds) and a square is 25,000 km, the speed of light is 14,400 squares per turn. Therefore a ship with 6 g's of acceleration can reach the speed of light in 33.333 days [14,400/6 = 2400 turns, 2400 x 20 minutes = 800 hours = 33.333 days] without actually moving at all. As written a 6g ship could just sit next to a planet for 5 weeks 'accelerating' to light-speed in place the whole time. The rules don't say they can't be refueled while 'accelerating'.

Point of Inquiry:
Are these general movement rules in the game or simply the rules for movement during combat?

If 'general movement' then carry on.

If 'combat movement' then I call a technical foul - application of rules outside of their intended area of applicability. ;)
[like quoting the 0-60 mph acceleration for a dragster and extrapolating that to building a track around the Earth so the dragster can accelerate to the speed of light and act as an interstellar transport ... the 0-60 times ARE appropriate for a drag strip, but NOT for interstellar travel.]
 
Last edited:
Since a turn is 20 minutes (1,200 seconds) and a square is 25,000 km, the speed of light is 14,400 squares per turn. Therefore a ship with 6 g's of acceleration can reach the speed of light in 33.333 days [14,400/6 = 2400 turns, 2400 x 20 minutes = 800 hours = 33.333 days] without actually moving at all. As written a 6g ship could just sit next to a planet for 5 weeks 'accelerating' to light-speed in place the whole time. The rules don't say they can't be refueled while 'accelerating'.

This is a textbook example of the fallacy of assuming that "reality" reflects rules rather than rules being a gross simplification of "reality" for purposes of easier gameplay.

('Reality' is in quotes to acknowledge that it's a fictional reality. But said fictional reality is still supposed to resemble the real world closely except in a few specific cases.)


Hans
 
Point of Inquiry:
Are these general movement rules in the game or simply the rules for movement during combat?

If 'general movement' then carry on.

If 'combat movement' then I call a technical foul - application of rules outside of their intended area of applicability. ;)
[like quoting the 0-60 mph acceleration for a dragster and extrapolating that to building a track around the Earth so the dragster can accelerate to the speed of light and act as an interstellar transport ... the 0-60 times ARE appropriate for a drag strip, but NOT for interstellar travel.]

They're the combat movement rules. The n-space movement rules are classic d=½AT².
 
Here we should define what do we understand as maneuverable. If you mean to turn you ship 180º, so going backwards, you're probably right.

That's what I meant. We're defining agility as a modifier against the ability to hit a target. From the point of view of the gunner, your agility is how far you can deviate from the course he expects between the time he decides to shoot and the time the beam reaches you - which of course includes his reaction time. The faster you can get your butt pointed where you want and put on an unexpected burst of thrust in an unexpected direction, and the bigger that burst of thrust when you do it, the harder it is for him to hit you. Speed and course are irrelevant - any desktop computer can calculate a firing solution given a set speed and course. It is only the degree to which you can deviate from those in a short period that make you a harder target.

One of the things that makes Traveller space combat 'unrealistic', IMHO is that we mostly assume a static (relative) start when combat begins. If (to put an example) we detect an enemy fleet in Jupiter and send our battleships from Earth at maximum acceleration to meet them, while they also accelerate to reach Earth ASAP (counting on arriving to Earth at a 0 relative speed), when the fleets meet at half point, their relative speeds will be tremendous, and they will at most shooting once against each other before being out of range again, having overpassed each other.

With detection ranges limited to a couple light-seconds, you don't boost away from the target to meet the enemy in deep space. If you know he's at Jupiter, it's only because you have something with sensors at Jupiter. Once he leaves Jupiter, he could slow down, speed up, change course, do just about anything, and you'd miss him - unless something with sensors managed to trail him, and he's likely to shoot down anything that tries that.

In another post, I compared it to trying to protect a neighborhood in utter darkness by walking around with a candle. Space is big enough and our detection gear weak enough that the only way to be sure the target is protected is to stay fairly close to the target. If you want to protect your house, best bet is to stay close to your house - candles on the lawn by the sidewalk, maybe a few helpers with candles a short distance in front of you can give you advance notice, but 6g acceleration and 4-500,000 mile detection ranges leave lots of room to miss each other when you're traversing hundreds of millions of miles.

Also, if you are decelerating when you meet the other fleet, you must have your ship show you stern to the enemy in order to fully decelerate, so making your spinals useless (they're assumed to fire only forward) until they have overpassed you.

Not so much a problem: calculate your attack, spin, shoot, spin back. With halfway decent inertial dampers, only a few seconds or tens of seconds are lost making the actual shot.
 
Not so much a problem: calculate your attack, spin, shoot, spin back. With halfway decent inertial dampers, only a few seconds or tens of seconds are lost making the actual shot.

I'm not so sure about how much will it take you for the whole maneover, and all this time you must stop decelerating (or at least reduce your deceleration, as you're not doing it directly stern of your ship)...
 
They're the combat movement rules. The n-space movement rules are classic d=½AT².

True. _However_ the MT rules definition of starship combat is "A starship combat situation occurs when a side of adventurers (in a spacecraft) encounters another space-faring craft - and violence is offered by either side." [MT Ref Man p 90] [1] By that definition 'combat' could never occur between two groups of NPC's, or between two groups of PC's. Apparently when the Imperial Navy and the Zhondani Navy fight it's not 'starship combat' unless there are PC's on one (and only one) side. This seems like a dubious definition to me.

Therefore saying that 'combat' movement can be used only in 'combat' is the same as saying 'The physical laws of the Universe change when one or more PC's are around.' That sounds like 'Exalted', not like 'Traveller.' YMMV, but I'd use the vehicle combat rules for starships, ignore the starship combat movement rules, and use the n-space movement rules for movement.

[1] I suppose you could argue that NPC's can be 'adventurers' and that therefore NPC fights could be 'starship combat' but note that the rules state that 'starship combat' occurs when '_a_' (singular) group of adventurers encounters another spacecraft. Therefore you will need to define one, and only one, of the NPC groups as 'adventurers'. Similarly for a fight between two groups of PC's to be 'starship combat' you would have to tag one, and only one, of them as 'adventurers'. I don't recall seeing a canonical definition of 'adventurers', so I'm not sure what the technical requirements are.
 
Therefore saying that 'combat' movement can be used only in 'combat' is the same as saying 'The physical laws of the Universe change when one or more PC's are around.'

No, it's saying "The abstractions, simplifications, and level of detail we use to emulate the physical laws of the universe for gaming purposes change when one or more PCs are around". Which is an eminently sensible way of doing things in a roleplaying game.


Hams
 
Back
Top