help me grok vector movement

[weasel fierce]

I have a feeling its not very hard, but the example in the CT book isnt making sense to me.

So, can someone give a basic rundown of ship vector movement (book 2) for moving a ship at a steady pace, turning, and accelerating, respectively ?

Also, how many tabletop inches does the maneuver drive rating correspond to ?

Confused, and thanks in advance!

Ivan

 

[weasel fierce]

I have a feeling its not very hard, but the example in the CT book isnt making sense to me.

So, can someone give a basic rundown of ship vector movement (book 2) for moving a ship at a steady pace, turning, and accelerating, respectively ?

Also, how many tabletop inches does the maneuver drive rating correspond to ?

Confused, and thanks in advance!

Ivan

 

[Supplement Four]

Ivan,

Just use the Range Band method in Starter Traveller. Or, use the method shown in Mayday.

It's so much simpler. And, no protractors and rulers!




Nutshell version

Range Band method.

Ships move in Range Bands, just like as suggested in Book 1 for personal combat.

Use a sheet of notebook paper for the Range Band method. You don't need to keep track of ships on a grid or hex map. Just use the notebook paper, Book 2 Starship Combat rules, and focus the game inside the player's ship (think of all those old submarine movies where all the tense action takes place on the bridge of the sub).

This is very role play oriented as it focusses on the player characters.

You, as GM, keep track of the range between two ships by using your notebook paper.

Each Range Band equals 10,000 km.

When a ship moves, it can move a number of bands equal to it's M-Drive rating.

So, if two ships are in the same Range Band (within 10,000 km of each other), they'll be in the same line on your notebook paper.

If one ship has an M-Drive rating of 3, while the other ship has an M-Drive rating of 1, then if the first ship accelerates at full power during the turn, it will be moving at 3 Range Bands per space combat turn (1000 seconds). If it continues to accelerate, it will cover 6 range bands per round, and so on.

The ship with the M-Drive rating can accelerate from relative stop to 1 range band per round in one space combat round. Then 2 range band per round. Then three. Etc.

So...

Both ships are in the same Range Band on Round 1. Both accelerate at full accleration during their Movement phase of Book 2 space combat.

The M-3 ship will move 3 Range Bands (line 3 on your notebook paper)

The M-1 ship will move 1 Range Band (line 1 on your notebook paper).

The distance between the two is 2 Range Bands (or 20,000 km).

On Round two, both ship accelerate to their fullest again.

The M-3 ship will move to line 9.

The M-1 ship will move to line 3.

Add the ship's current velocity to it's current Range Band position to see how far it will move.

The distance between them is 6 Range Bands, or 60,000 km.

Get it?

It's simple.

The amount of acceleration a ship put into moving in a direction is referred to as its velocity, so, on Round 1 above, the M-3 ship had a velocity of 3. During Round 2, it's velocity was increased to 6. (On round 1, it moved from Range Band 0 to RB 3 with it's velocity of 3. Then, on round 2, it moved from RB 3 to RB 9, with it's velocity of 6.)

The M-1 ship had a velocity of 1 on round 1 and a velocity of 2 on round 2. So, this ship moved to RB 1 on round 1, and then RB 3 on round 2.

A ship can only change its velocity by an amount equal to the ship's M-Drive.

So, if the M-3 ship wanted to close distance with the other ship after round 2, it could only decrease it's velocity to 3 (it can't go to zero in one round having spent two rounds accelerating).

On Round 3, let's say the M-3 decreases it's velocity by 1 (it can decrease it up to 3, if it wants). It's velocity, at the end of the round, is decreased from 6 to 5.

This means, the M-3 ship would end the round in RB 14.

If the M-1 ship keeps accelerating, then, on Round 3, it will have a velocity of 3. So, from the first round, it would move to RB1, then RB 3, then RB 6.

At the end of round 3, the distance between the two ships is 8 Range Bands, or 80,000 km.

Of course, you see the importance of having a good maneuver drive...

 

[Supplement Four]

Ivan,

Just use the Range Band method in Starter Traveller. Or, use the method shown in Mayday.

It's so much simpler. And, no protractors and rulers!




Nutshell version

Range Band method.

Ships move in Range Bands, just like as suggested in Book 1 for personal combat.

Use a sheet of notebook paper for the Range Band method. You don't need to keep track of ships on a grid or hex map. Just use the notebook paper, Book 2 Starship Combat rules, and focus the game inside the player's ship (think of all those old submarine movies where all the tense action takes place on the bridge of the sub).

This is very role play oriented as it focusses on the player characters.

You, as GM, keep track of the range between two ships by using your notebook paper.

Each Range Band equals 10,000 km.

When a ship moves, it can move a number of bands equal to it's M-Drive rating.

So, if two ships are in the same Range Band (within 10,000 km of each other), they'll be in the same line on your notebook paper.

If one ship has an M-Drive rating of 3, while the other ship has an M-Drive rating of 1, then if the first ship accelerates at full power during the turn, it will be moving at 3 Range Bands per space combat turn (1000 seconds). If it continues to accelerate, it will cover 6 range bands per round, and so on.

The ship with the M-Drive rating can accelerate from relative stop to 1 range band per round in one space combat round. Then 2 range band per round. Then three. Etc.

So...

Both ships are in the same Range Band on Round 1. Both accelerate at full accleration during their Movement phase of Book 2 space combat.

The M-3 ship will move 3 Range Bands (line 3 on your notebook paper)

The M-1 ship will move 1 Range Band (line 1 on your notebook paper).

The distance between the two is 2 Range Bands (or 20,000 km).

On Round two, both ship accelerate to their fullest again.

The M-3 ship will move to line 9.

The M-1 ship will move to line 3.

Add the ship's current velocity to it's current Range Band position to see how far it will move.

The distance between them is 6 Range Bands, or 60,000 km.

Get it?

It's simple.

The amount of acceleration a ship put into moving in a direction is referred to as its velocity, so, on Round 1 above, the M-3 ship had a velocity of 3. During Round 2, it's velocity was increased to 6. (On round 1, it moved from Range Band 0 to RB 3 with it's velocity of 3. Then, on round 2, it moved from RB 3 to RB 9, with it's velocity of 6.)

The M-1 ship had a velocity of 1 on round 1 and a velocity of 2 on round 2. So, this ship moved to RB 1 on round 1, and then RB 3 on round 2.

A ship can only change its velocity by an amount equal to the ship's M-Drive.

So, if the M-3 ship wanted to close distance with the other ship after round 2, it could only decrease it's velocity to 3 (it can't go to zero in one round having spent two rounds accelerating).

On Round 3, let's say the M-3 decreases it's velocity by 1 (it can decrease it up to 3, if it wants). It's velocity, at the end of the round, is decreased from 6 to 5.

This means, the M-3 ship would end the round in RB 14.

If the M-1 ship keeps accelerating, then, on Round 3, it will have a velocity of 3. So, from the first round, it would move to RB1, then RB 3, then RB 6.

At the end of round 3, the distance between the two ships is 8 Range Bands, or 80,000 km.

Of course, you see the importance of having a good maneuver drive...

 

[Supplement Four]

If you want a more role-playing focussed scenario, then use the Range Band method I describe above.

But, if you're more of a wargamer, and want to see the plot on a hex map (or a square grid), then the Range Band method lends itself easily to this type of play.

Use counters for your ships. Use a hex map for the combat area.

Each hex (or square) equals 1 Range Band. So, each hex equals 10,000 km.

The rules stay the same. A ship can move a number of hexes (Range Bands) equal to it's M-Drive each round. Or, in other words, a ship can add-to or subtract-from it's Velocity each round an amount equal to it's M-Drive.

The Easiest Way to keep track of Range Band movement using a hex grid...

When a ship moves, count a number of hexes, in a straight line, equal to the ship's velocity last combat turn. (Or, answer this question: If the ship made no changes at all, where would it be at the end of this round.)

Once you've located the hex of the ship's future position of where it will be, had it made zero changes to velocity, at the end of the round, put your finger on it...from this point, the ship can alter course a number of hexes, in any direction, equal to it's M-Drive..

So, if a ship, with an M-2 M-Drive, has a velocity of 22 on Round 6, then, on Round 7, count, in a straight line (along the same course) 22 hexes in front of the ship. Once you reach that last hex, you can alter the future position of the ship, in any direction, by 0-2 hexes.

Picture a hex. Clock wise, around it: Side 1 is "acclerate straight ahead". Side 2 and Side 3 is a "turn to starboard". Side 4 is "decelerate". And, Side 5 and Side 6 are both "turns to port".

If your new position is to Sides 2,3,4,5, then your ship is banking a bit (little bit), and your velocity number stays the same (eventhough, technically, since you are altering course, you would be changing your velocity in the real world). If your new position is 1 or 2 hexes past Side 1, your ship is accelerating, and your new velocity will reflect that change.

If your new position is 1 or 2 hexes past Side 4, then you are decelerating, and your new velocity will be lowered to reflect that change.

Going back to the example: If the M-2 Ship, moving at a Velocity of 22, decides to decelerate by 1, then...

...you will count 22 hexes along your current path, in a straight line, across the hex board. Once you find that hex, move it past Side 4 by 1 hex. Your ship will actually only accelerate 21 hexes this round instead of 22 (you've slowed down by 1 hex).

If you want to come to a full relative stop in space, it will take you 11 space combat turns (11,000 seconds).

R1: Drop to V20
R2: Drop to V18
R3: Drop to V16
R4: Drop to V14
R5: Drop to V12
R6: Drop to V10
R7: Drop to V8
R8: Drop to V6
R9: Drop to V4
R10: Drop to V2
R11: Drop to V0.

Note that, from your original velocity of 22, it will not only take you 3.06 hours to come to a relative stop (11,000 seconds), but you will also travel 1.1 million kilometers from the point you decide to come to a relative stop to the point at which your ship actually comes to relative rest.

This isn't STAR WARS. You've got to flip your ship around and use the full thrust of the M-Drive to slow your ship down...and you've got to slow down for an amount of time equal to that at which it took you to accelerate to that speed originally.

"Where'd the planet go? I told you to make orbit"

"But sir! Our approach was too fast!"




I, personally, use the Range Band method on the notebook paper as discussed in the above post as it focuses the game on the players (inside the player's ship), and Range to target is really the only important factor from mapping a combat (a ship has over 15 minutes during a space combat turn with which to orient the ship's lasers and fire them...and a ship can be travelling in any direction, regardless of where the bow is facing as long as it is not accelerating or decelerating).

The hex board and counters (and especially the confusing vector movement system in Book 2) is too much to deal with.

The Range Band method, to me, is perfect for role playing.

Starter Traveller and Book 2 space combat are my CT Space Combat system of choice.

-S4

 

[Supplement Four]

If you want a more role-playing focussed scenario, then use the Range Band method I describe above.

But, if you're more of a wargamer, and want to see the plot on a hex map (or a square grid), then the Range Band method lends itself easily to this type of play.

Use counters for your ships. Use a hex map for the combat area.

Each hex (or square) equals 1 Range Band. So, each hex equals 10,000 km.

The rules stay the same. A ship can move a number of hexes (Range Bands) equal to it's M-Drive each round. Or, in other words, a ship can add-to or subtract-from it's Velocity each round an amount equal to it's M-Drive.

The Easiest Way to keep track of Range Band movement using a hex grid...

When a ship moves, count a number of hexes, in a straight line, equal to the ship's velocity last combat turn. (Or, answer this question: If the ship made no changes at all, where would it be at the end of this round.)

Once you've located the hex of the ship's future position of where it will be, had it made zero changes to velocity, at the end of the round, put your finger on it...from this point, the ship can alter course a number of hexes, in any direction, equal to it's M-Drive..

So, if a ship, with an M-2 M-Drive, has a velocity of 22 on Round 6, then, on Round 7, count, in a straight line (along the same course) 22 hexes in front of the ship. Once you reach that last hex, you can alter the future position of the ship, in any direction, by 0-2 hexes.

Picture a hex. Clock wise, around it: Side 1 is "acclerate straight ahead". Side 2 and Side 3 is a "turn to starboard". Side 4 is "decelerate". And, Side 5 and Side 6 are both "turns to port".

If your new position is to Sides 2,3,4,5, then your ship is banking a bit (little bit), and your velocity number stays the same (eventhough, technically, since you are altering course, you would be changing your velocity in the real world). If your new position is 1 or 2 hexes past Side 1, your ship is accelerating, and your new velocity will reflect that change.

If your new position is 1 or 2 hexes past Side 4, then you are decelerating, and your new velocity will be lowered to reflect that change.

Going back to the example: If the M-2 Ship, moving at a Velocity of 22, decides to decelerate by 1, then...

...you will count 22 hexes along your current path, in a straight line, across the hex board. Once you find that hex, move it past Side 4 by 1 hex. Your ship will actually only accelerate 21 hexes this round instead of 22 (you've slowed down by 1 hex).

If you want to come to a full relative stop in space, it will take you 11 space combat turns (11,000 seconds).

R1: Drop to V20
R2: Drop to V18
R3: Drop to V16
R4: Drop to V14
R5: Drop to V12
R6: Drop to V10
R7: Drop to V8
R8: Drop to V6
R9: Drop to V4
R10: Drop to V2
R11: Drop to V0.

Note that, from your original velocity of 22, it will not only take you 3.06 hours to come to a relative stop (11,000 seconds), but you will also travel 1.1 million kilometers from the point you decide to come to a relative stop to the point at which your ship actually comes to relative rest.

This isn't STAR WARS. You've got to flip your ship around and use the full thrust of the M-Drive to slow your ship down...and you've got to slow down for an amount of time equal to that at which it took you to accelerate to that speed originally.

"Where'd the planet go? I told you to make orbit"

"But sir! Our approach was too fast!"




I, personally, use the Range Band method on the notebook paper as discussed in the above post as it focuses the game on the players (inside the player's ship), and Range to target is really the only important factor from mapping a combat (a ship has over 15 minutes during a space combat turn with which to orient the ship's lasers and fire them...and a ship can be travelling in any direction, regardless of where the bow is facing as long as it is not accelerating or decelerating).

The hex board and counters (and especially the confusing vector movement system in Book 2) is too much to deal with.

The Range Band method, to me, is perfect for role playing.

Starter Traveller and Book 2 space combat are my CT Space Combat system of choice.

-S4

 

[far-trader]

Originally posted by weasel fierce:
I have a feeling its not very hard, but the example in the CT book isnt making sense to me.

So, can someone give a basic rundown of ship vector movement (book 2) for moving a ship at a steady pace, turning, and accelerating, respectively ?

No problem (I think ):

1 Moving a ship at a steady pace. I presume you mean simply coasting at a set speed. Starting from a velocity of zero, in orbit around a size 8 world for example, our typical Free-Trader accelerates at 1G for one turn (1000 seconds). This results in a scale vector of 100mm (representing 10,000km). That would translate to a speed of about 36,000kph. To simply maintain that speed you just cut your acceleration (do not use maneuver drive) and coast, adding a scale vector of 100mm each turn in a straight line unless otherwise acted on.

2 Turning. A bit trickier to explain. From your ship's current position plot it's current vector. To continue the example above after our ship has moved for several turns we spot something we want to look at closer. It is (for simplicity) ahead and to the side of our current plot. So to get closer to investigate we will need to turn. Plot the current vector (100mm) and then from the end of that (the point farthest from the ship) draw another vector with a maximum length equal to the ship's acceleration (in this case 1G so 100mm) in any direction. It can be backwards, forwards, sideways, or anywhere inbetween. Then draw a line between the end of that vector and the ship, that is where your turn will take you in the next 1000 seconds. Repeat until you are as close as you want to get.

3 Accelerating. To continue with the example above, you draw nearer the interesting contact and it turns out to be trouble, time to run. Your current vector has once again come out to a simple 100mm, unfortunately it is directly towards the pirate ship. That is not good. You decide to run the other way (back to port and help) and plotting the vectors will result in you coming to a stop in one turn. The next turn you are still accelerating in the same direction and will move 100mm (10,000km). In the thrid turn you again add your 100mm vector to your current 100mm vector and move 200mm (20,000km) building up your speed to about 72,000kph. In the fourth turn you continue to add your full 1G acceleration for another 100mm added to your current vector of 200mm, for a total of 300mm (30,000km) covered in that turn with a current speed of 108,000kph. And so on, until you change your direction of acceleration.

Hope that clears it up.

Originally posted by weasel fierce:
Also, how many tabletop inches does the maneuver drive rating correspond to ?

Well the book deals (largely) in metric. Each 1G of thrust will produce a scale vector of 100mm in each 1000 second turn. The scale is 1:100million so each 100mm is 10,000km. A quick conversion to inches (rounded) would be 4" per G per turn representing about 6300 miles.

 

[far-trader]

Originally posted by weasel fierce:
I have a feeling its not very hard, but the example in the CT book isnt making sense to me.

So, can someone give a basic rundown of ship vector movement (book 2) for moving a ship at a steady pace, turning, and accelerating, respectively ?

No problem (I think ):

1 Moving a ship at a steady pace. I presume you mean simply coasting at a set speed. Starting from a velocity of zero, in orbit around a size 8 world for example, our typical Free-Trader accelerates at 1G for one turn (1000 seconds). This results in a scale vector of 100mm (representing 10,000km). That would translate to a speed of about 36,000kph. To simply maintain that speed you just cut your acceleration (do not use maneuver drive) and coast, adding a scale vector of 100mm each turn in a straight line unless otherwise acted on.

2 Turning. A bit trickier to explain. From your ship's current position plot it's current vector. To continue the example above after our ship has moved for several turns we spot something we want to look at closer. It is (for simplicity) ahead and to the side of our current plot. So to get closer to investigate we will need to turn. Plot the current vector (100mm) and then from the end of that (the point farthest from the ship) draw another vector with a maximum length equal to the ship's acceleration (in this case 1G so 100mm) in any direction. It can be backwards, forwards, sideways, or anywhere inbetween. Then draw a line between the end of that vector and the ship, that is where your turn will take you in the next 1000 seconds. Repeat until you are as close as you want to get.

3 Accelerating. To continue with the example above, you draw nearer the interesting contact and it turns out to be trouble, time to run. Your current vector has once again come out to a simple 100mm, unfortunately it is directly towards the pirate ship. That is not good. You decide to run the other way (back to port and help) and plotting the vectors will result in you coming to a stop in one turn. The next turn you are still accelerating in the same direction and will move 100mm (10,000km). In the thrid turn you again add your 100mm vector to your current 100mm vector and move 200mm (20,000km) building up your speed to about 72,000kph. In the fourth turn you continue to add your full 1G acceleration for another 100mm added to your current vector of 200mm, for a total of 300mm (30,000km) covered in that turn with a current speed of 108,000kph. And so on, until you change your direction of acceleration.

Hope that clears it up.

Originally posted by weasel fierce:
Also, how many tabletop inches does the maneuver drive rating correspond to ?

Well the book deals (largely) in metric. Each 1G of thrust will produce a scale vector of 100mm in each 1000 second turn. The scale is 1:100million so each 100mm is 10,000km. A quick conversion to inches (rounded) would be 4" per G per turn representing about 6300 miles.

 

[Enoff]

http://www.bitsuk.net/Archive/GameRules/files/MayDay.pdf

 

[Enoff]

http://www.bitsuk.net/Archive/GameRules/files/MayDay.pdf

 

[Ptah]

Hi Ivan,

The description in LBB2 can be a little obscure if you are not already very comfortable with vector addition. It really is basic vector addition as can be found in many a text book.

This site has a nice description of the basic concept:

http://www.glenbrook.k12.il.us/GBSSCI/PHYS/mmedia/vectors/va.html


To your specific questions:

So, can someone give a basic rundown of ship vector movement (book 2) for moving a ship at a steady pace, turning, and accelerating, respectively ?

For a steady pace, don't accelerate.

Turning, draw you current vector, then draw the longest vector you can in the direction you want to go, keep doing this until your vector is in the direction you want.

Acceleration, keep adding vectors to your current direction.

If you have a hex mat the Mayday approach, linked above I believe, does the same thing but you can ditch the protractor and ruler!

Finally the range band approach is very good and an even more accurate representation of actual movement if only two ships are involved. The reason being LBB2 and Mayday (IIRC) ignore the third dimension. With two combatants only distance matters, since a straight line can always be drawn between two points range bands (a straight line)are always an accurate representation. Of course if you throw in a planet all bets are off.

-Ptah

 

[Ptah]

Hi Ivan,

The description in LBB2 can be a little obscure if you are not already very comfortable with vector addition. It really is basic vector addition as can be found in many a text book.

This site has a nice description of the basic concept:

http://www.glenbrook.k12.il.us/GBSSCI/PHYS/mmedia/vectors/va.html


To your specific questions:

So, can someone give a basic rundown of ship vector movement (book 2) for moving a ship at a steady pace, turning, and accelerating, respectively ?

For a steady pace, don't accelerate.

Turning, draw you current vector, then draw the longest vector you can in the direction you want to go, keep doing this until your vector is in the direction you want.

Acceleration, keep adding vectors to your current direction.

If you have a hex mat the Mayday approach, linked above I believe, does the same thing but you can ditch the protractor and ruler!

Finally the range band approach is very good and an even more accurate representation of actual movement if only two ships are involved. The reason being LBB2 and Mayday (IIRC) ignore the third dimension. With two combatants only distance matters, since a straight line can always be drawn between two points range bands (a straight line)are always an accurate representation. Of course if you throw in a planet all bets are off.

-Ptah

 

[far-trader]

Originally posted by Ptah:
Hi Ivan,

The description in LBB2 can be a little obscure if you are not already very comfortable with vector addition. It really is basic vector addition as can be found in many a text book.

Heh, you know, when I saw this I had to wonder, do they even still teach vector geometry/algebra in primary/high school?

 

[far-trader]

Originally posted by Ptah:
Hi Ivan,

The description in LBB2 can be a little obscure if you are not already very comfortable with vector addition. It really is basic vector addition as can be found in many a text book.

Heh, you know, when I saw this I had to wonder, do they even still teach vector geometry/algebra in primary/high school?

 

[etherflyer]

Originally posted by far-trader:
Heh, you know, when I saw this I had to wonder, do they even still teach vector geometry/algebra in primary/high school?

I use Mayday to teach vectors in high school.

 

[etherflyer]

Originally posted by far-trader:
Heh, you know, when I saw this I had to wonder, do they even still teach vector geometry/algebra in primary/high school?

I use Mayday to teach vectors in high school.

 

[weasel fierce]

allright. That helps clear up things. I'll have to break out the mini's or counters and play around with it a bit.

 

[weasel fierce]

allright. That helps clear up things. I'll have to break out the mini's or counters and play around with it a bit.

 

[far-trader]

One quick bit of advice, you can skip the whole planetary gravity effects bit in my opinion, it'll simplify things a bit and you won't miss it. It never made much sense since Traveller ships seem to operate with an anitgravity effect that cancels out local gravity.

 

[far-trader]

One quick bit of advice, you can skip the whole planetary gravity effects bit in my opinion, it'll simplify things a bit and you won't miss it. It never made much sense since Traveller ships seem to operate with an anitgravity effect that cancels out local gravity.