Putting Together 'Starship of the Line'

[dccarles]

I've had a bunch of ideas about space combat bouncing around in my head for a while, and with the advent of Traveller 5 I think I'm finally going to put them together.

My main interest in Traveller has been Trillion Credit Squadron, due to lack of available players. I'll design a ship for a specific world, and then design another ship to beat that one, to be built by a rival. By now I have something resembling Conway's All The World's Fighting Ships for TL 10-13 navies.

My version of High Guard (which I call Starship of the Line to avoid confusion) will have the following features/design priorities:
1) An emphasis on command, control and initiative. (I'm considering using a MegaTraveller-like 'interrupt' system to determine sequence of play.)
2) An abstracted movement system, like the original Book 5; however, ships can be grouped under command of an admiral.
3) An emphasis on (abstracted) movement over firepower. Dividing one's force to outflank the enemy may give a fleet a tactical advantage. (This gives the player many meaningful choices on a fleet level, rather than messing about with allocating the fire of specific ships.)
4) Small engagements should take skilled players no more than an hour; large-scale engagements about four hours.
5) Compatibility with Traveller 5.

This thread, then, is for ideas, comments, playtest reports, observations, flames. Enjoy.

--Devin

 

[dccarles]

Initiative and Maneuver

I have some ideas for initiative and maneuver which, I think, are quite clever. They should be, because I stole them from the best possible sources.

Assume the two opposing sides are each arranged in groups of several ships (each printed on a 3x5" index card), not exceeding the level of their admiral's Fleet Tactics skill. Each group is arranged to oppose at most one enemy group. Both sides also have a reserve (though that isn't important here.) Each fleet is commanded by a grand admiral, who may or may not also command a group.

[I'm not explaining just how ships are grouped or how the line of battle is formed just yet.]

On the first and each subsequent turn, the grand admiral of each side rolls an opposed task:

To gain the initiative in a fleet action.
(Int + Fleet Tactics) > Difficult (3D).
Opposed (1). Becomes a Formidable (4D) task if the opponent had the initiative last turn, or if suffering from tactical surprise. Becomes a Staggering (5D) task if suffering from complete surprise.

Whoever wins gains the initiative and may, if they desire, put forth one of their groups to act by declaring a specific action, optionally declaring whether or not the action is hasty or cautious. Alternately, they may allow the other player to go first. When this is done, put a marker for the group on the table. This is the first action in the action stack.

Once a group is put forth, any group on the other side may attempt to interrupt it, declaring its action as it does so.

To interrupt another group.
(Int + Fleet Tactics + Optional Agility) > Difficult (3D).
Cooperative (1, Fleet Tactics, grand admiral only.) Opposed (1). Task difficulty increases one level if opponent declared its action as hasty. Task difficulty decreases one level if opposing group declared its action as cautious. Record Agility points as they are spent.

[I'll explain Agility use later.]

If the interrupt is successful, place the interrupting group's marker above the interrupted group's; otherwise, put it below. The interrupting group is committed to action.

Groups that are interrupting may themselves be interrupted until all groups are committed to the action stack, or both sides decline to commit further groups. Once this is done, each action is resolved, from top to bottom.

[Some notes: firing secondary weapons is not an action, it is something that is done during another action. Firing spinal weapons does, because it requires the ship be oriented toward the enemy, i.e., use maneuver Gs. Actions require maneuver Gs, which then can't be used for evasion.

Sample actions: change range, take command, disengage, fire spinal mounts, break the line, missile screen, charge!]

--Devin

 

[pendragonman]

Have you looked at the "fighting instructions" of the 18th Century British Navy?

 

[dccarles]

No, I haven't. But now I think of it, it must be on Gutenberg somewhere. I'll go have a look at it now.

 

[robject]

3) An emphasis on (abstracted) movement over firepower. Dividing one's force to outflank the enemy may give a fleet a tactical advantage. (This gives the player many meaningful choices on a fleet level, rather than messing about with allocating the fire of specific ships.)

That's pretty clever.

 

[dccarles]

Hit Resolution

I'm trying to make hit resolution pretty simple. To that end, I'm making some assumptions.

When a task force is acting, it is said to be its phase. During its phase it may, in order,
1) play a maneuver,
2) launch and recover small craft and missiles,
3) fire beams,
4) resolve damage to targets,
5) resolve noncombat actions like damage control, awakening the frozen watch, communications tasks, etc.

In this post I'm only dealing with step 3.

Every ship rolls an attack task for every target it fires on in the beam fire step. As fire control data is shared throughout a ship, only one roll is necessary, though the attack DMs for individual weapons may vary.

To hit a craft with beam weapons.
(10 + Attack DM - Defense DM) > Difficulty (nD)
Cooperative (see below). Difficulty at close and short range is Difficult (3D), at long range Formidable (4D) and Hopeless (6D) at extreme range. Increase the difficulty one level if the target is evading. Decrease the difficulty one level if the target can't maneuver.

A ship's attack DM is its fire control rating + crew's Ship Gunnery skill + weapon accuracy. Its defense DM is its size DM + unspent Agility + Pilot. The captain's Ship Tactics may, in both cases, may be used as a cooperative DM.

[A note: default skill of 3 is average for trained naval crews; some crews may have exceptional skills in some specific areas. Fire control rating is based on the ship's computer and sensors.]

If the number rolled is exactly the number required, then half of the weapons, rounding up.

If the number rolled on the dice is higher than the number required, then fewer than half the weapons will hit. For every multiple of the number of dice rolled, or fraction, the roll fails by, the number of weapons that hit is halved again.

If the number rolled on the dice is less than the number required, then fewer than half the weapons will miss. For every full multiple of the number of dice rolled the roll beats the target number, the number of misses is halved.

Example: The CR Ashtabula fires 20 triple laser turrets at a Zhodani Zhdits destroyer escort at short range. The frigate is evading, and all skills are 3.

The attack DM is 17 (9 for the Ashtabula's 9/fib computer, 3 for the crew's skill, 3 for the captain's Ship Tactics, and 2 for the accuracy of the lasers.) The defense DM is 14 (6 for the Zhdits' agility, 3 for the crew's skill, 3 for the captain's skill, and +2 for the size DM.) The roll necessary to hit, then, is 13.

Sixty weapons are being fired, with an RoF of 2, making 120 shots in total. The task is Formidable (4D), and the Imperial player rolls a 9. This is 4 less than 13, the number needed, so one quarter of the shots miss, that is, three quarters hit. (If the roll had been one greater, only half the shots would have hit.) A total of 90 laser bursts pepper the Zhodani.

 

[Whipsnade]

That's pretty clever.

Robject,

Flank observers? Actually, that's right out of various late 19th/early-to-mid 20th Century, gunnery based, naval tactics.

Many navies came up with the idea about the same time. Fire control was the BIG ISSUE in naval technology from the latter decades of the 1800s through WW2. The RN was badly embarrased by it's poor firing at Alexandria in the 1880s and the USN was equally chagrined after 1898. Guns and their ranges had gotten so big that the old ways of aiming them just didn't work anymore.

It was the RN that first applied the idea of "flank observers". They actually trained light units to flank an opponent and them signal "forward observer" type information back to the gun line. During WW2, the IJN actually pulled off this trick, albeit briefly, during the Battle of the Komandorski Islands.

Of course, the role of flank observer was simply added to the myriad jobs that light units perform while screening larger units and one of those myriad jobs was preventing the opposing light units from accomplishing any of their jobs!

Seeing as all Traveller ship comagt systems and games have neatly sidestepped the Fire Contorl/ECM/ECCM issue by folding it into such things as computer ratings and sensor rolls, adding a wrinkle like flank observers would be a nice way to introduce more tactical thinking into the mix.


Have fun,
Bill

 

[pendragonman]

Example: The CR Ashtabula fires 20 triple laser turrets at a Zhodani Zhdits destroyer escort at short range. The frigate is evading, and all skills are 3.

The attack DM is 17 (9 for the Ashtabula's 9/fib computer, 3 for the crew's skill, 3 for the captain's Ship Tactics, and 2 for the accuracy of the lasers.) The defense DM is 14 (6 for the Zhdits' agility, 3 for the crew's skill, 3 for the captain's skill, and +2 for the size DM.) The roll necessary to hit, then, is 13.

So, in your calculation, there is no effect from the Zhdits own computers (effectively providing ECM) on the defensive side? Seems a little extreme...

Also, have you thought of having a maximum number of targets per round for a given ship to fire at? Something like a master fire director?

IMTU (your results will vary) I use half the firing ship's computer number (round up) as a maximum number of ships able to be tracked for targeting purposes. So a Beowulf with a 1 or a 1 Bis would only be able to target one ship, a Gazelle with its model 6 would be able to track 3, and a Chrysanthemum with its model 9, five.

 

[dccarles]

So, in your calculation, there is no effect from the Zhdits own computers (effectively providing ECM) on the defensive side? Seems a little extreme...

It is. I've changed my mind on this point, exactly because of that problem:
Attack DM = Weapon Accuracy + Computer + Gunnery;
Defense DM = Computer + Pilot.

Pilot skill is limited to the ship's agility or less. Agility doesn't directly help a ship avoid incoming fire, but the evade maneuver does (2 agility points = +1 diff mod to incoming fire, except at close range.)

I'm not married to any particular task profile (or system) yet. The basics of the game are sketched out in my head, and I'm busy writing them down when I get time. When I have a comprehensible rules set, I'll start playtesting in earnest.

I'm handwaving the number of targets issue, allowing even civilian ships to fire at as many enemy ships as they like. I assume every ship in the 25th century has planar-array electronically-scanning radar, or the like; an equivalent of the US Navy's Aegis system is necessary for dealing with micrometeors and other kinds of space junk. The gameplay reasons, however, are that it would add complexity (one more number to remember), and that it's not a decision the fleet admiral needs to make - it's the job of his subordinates (the task force admirals and ship captains.)


--Devin

 

[dccarles]

Robject,
Seeing as all Traveller ship comagt systems and games have neatly sidestepped the Fire Contorl/ECM/ECCM issue by folding it into such things as computer ratings and sensor rolls, adding a wrinkle like flank observers would be a nice way to introduce more tactical thinking into the mix.

I won't actually have flank/forward observers, because the limits of the speed of light make them less useful. Specifically, the firing ship would be using a targeting solution that is seconds old.

I do assume, though, that ship designers regularly put the heaviest armour where a ship is most likely to be hit. The advantage of flanking the opponent means that at least one of the flankers will be able to hit the vulnerable areas (e.g., the maneuver exhaust, boat dock doors, etc.)

--Devin

 

[Whipsnade]

I won't actually have flank/forward observers, because the limits of the speed of light make them less useful. Specifically, the firing ship would be using a targeting solution that is seconds old.

DCCarles,

shrug Your firing solution is seconds old already. Increasing that time lag by a few tens of percent isn't going to make much difference.

Your concerns also ignore missiles and fixate solely on beams.

I do assume, though, that ship designers regularly put the heaviest armour where a ship is most likely to be hit. The advantage of flanking the opponent means that at least one of the flankers will be able to hit the vulnerable areas (e.g., the maneuver exhaust, boat dock doors, etc.)

"Chinks" in the armor? Please.

You're firing at light-second distances and you actually believe you can [aim at boat bay doors? Or that armor is made up of discrete slabs laid down belts like something out of the Dreadnought Age instead of being a measure of a ship's overall toughness?

Whatever.


Have fun,
Bill

 

[robject]

You're firing at light-second distances and you actually believe you can [aim at boat bay doors? Or that armor is made up of discrete slabs laid down belts like something out of the Dreadnought Age instead of being a measure of a ship's overall toughness?

I recently got a thought similar to that one from a guy who's never played Traveller before, but was familiar with other SF RPGs. He suggested that firing two batteries in one attack should produce twice the penetration.

It's possible of course, but I simply told him that Traveller combat involved saturating a volume in which the target is likely to be, with multiple actual shots, and all that is abstracted into one "attack" roll. So there's "no" chance that two different shots will hit exactly the same spot. Or something like that. (But perhaps you could slave them into one super-battery... ah whatever).

I suspected he was thinking of Star Wars dogfights or Star Trek battles (which is how we all picture space combat anyway, let's face it).

 

[chshrkt]

DCCarles,

shrug Your firing solution is seconds old already. Increasing that time lag by a few tens of percent isn't going to make much difference.

Your concerns also ignore missiles and fixate solely on beams.

Go look at post #6, he specifically stated that he is only talking about beam weapons right now.

"Chinks" in the armor? Please.

You're firing at light-second distances and you actually believe you can [aim at boat bay doors? Or that armor is made up of discrete slabs laid down belts like something out of the Dreadnought Age instead of being a measure of a ship's overall toughness?

Whatever.

I don't believe he was talking about aimed shots at the bay doors. When you fire on a target with multiple weapons or shots, they will not all hit exactly the same spot, but will instead be spread over a particular area, and one of those shots could likely hit the bay doors or exhaust ports, which might be more lightly armored than the hull and thus vulnerable.

Your dismissive and condescending attitude is rather distasteful.

 

[dccarles]

DCCarles,

shrug Your firing solution is seconds old already. Increasing that time lag by a few tens of percent isn't going to make much difference.

I'm talking about the distinction between engaging at one light-second and engaging at four light-seconds - forward observers, rather than flank observers. (Missiles, though, could have control handed off to them.)

In any case, remember the surface area to hit decreases proportional to the square of the range. Also remember that the (presumably) evading ship will be accelerating in an indeterminable direction.

So, if you have a 1 m2 target at one light-second, and it's the largest target you're certain to hit with a laser, at 1.1 light-seconds the beam is only 83% (1/1.21 x 100%) likely to hit.

That's not so bad, I suppose. But now let's look at a maneuvering target.

Now assume it's maneuvering at one G, and you have a bunch of lasers to cover every space it could be. It can move 19.2 m in the two seconds it takes for light to travel to you and back again (processing time is assumed to be trivial at these ranges), making the target uncertainty area (19.2 x 2 + 1= 39.4^2 = 1552 m2. Again, let's assume you have a bunch of lasers with RoFs high enough to cover this area to always hit this target, but not one any smaller.

At 1.1 light-seconds, it can move up to 23.2 m. The target uncertainty area is now 47.4^2 = 2247 m2. That's a factor of x1.45 in the difficulty, i.e., the number of lasers firing to be certain to hit this thing. And the target is also relatively smaller: 1.21 times smaller, in fact, as we showed before. We have a difficulty increase of x1.75 for a 10% increase in range.

You're firing at light-second distances and you actually believe you can aim at boat bay doors?

Gaaaaah, no!

Rereading what I wrote, the misunderstanding is plainly my fault - what I wrote was very misleading. I'm thinking more about the armour distribution on MBTs, with the heaviest armour up front. Where the armour envelope has to be penetrated for design purposes, it's better to put the holes anywhere but the front. (One reason flexi-mount hull MGs have gone out of fashion. Also note that imaging systems and periscopes always open on the top of the turret, not the front.) Any hits on weak points come at random.

I'm also assuming that the maneuver drive exhaust is always a weak point. (IMTU, maneuver drive is not reactionless; there always needs to be some mass spewed out the back end. Maneuver drives rely on inertial enhancers to limit the amount of reaction mass they need.) There's always a hole at the back, and the more armour you put over the inertial enhancers the less efficient they are.

This saves the law of conservation of linear momentum, though at the expense of the the first law of thermodynamics. Luckily, no one - absolutely no scientist on any world at any time IMTU, not even Grandfather - has noticed this.

Or that armor is made up of discrete slabs laid down belts like something out of the Dreadnought Age instead of being a measure of a ship's overall toughness?

I'm assuming it's a bit both. In my damage system, which I'll do right after this post, a weapon either fully penetrates, partially penetrates or fails to penetrate at all.

When I think about it, though, halving the armour for flankers is brutally unfair, considering I'm using a logarithmic system for damage. (A damage-4 laser is about twice as powerful as a damage-2 laser.) A much better way to do it would be armour factor - 2.

--Devin

 

[dccarles]

I suspected he was thinking of Star Wars dogfights or Star Trek battles (which is how we all picture space combat anyway, let's face it).

...Actually, I picture High Guard space combat as being like Trafalgar, with missiles (the nearest thing small ships have to an equalizer) and fighters. In other words, huge behemoths blowing each other's doors off, with a few daring and decisive maneuvers, and lots of light forces busily engaged in acts of pointless heroism.

Oh, and ninjas. Can't forget the ninjas; they're what keep the pirates away.

--Devin

 

[dccarles]

Your dismissive and condescending attitude is rather distasteful.

It's okay; for one, what I wrote assumed too much mind-reading, and second, I'm a big boy who can take a few punches on teh internets.



--Devin

 

[dccarles]

Weapons, Penetration and Damage

I'm going to skip defenses, because I haven't entirely figured out how they're going to work yet. (Meson screens will probably work roughly like they do in Battle Rider - a successful block stops the attack, a failed one reduces the damage.)

All weapons (except meson guns) have a penetration modifier score and a damage score. These are listed for short range. It is worthwhile to note that damage does not depend upon range - the same amount of energy is being pumped out - but the penetration modifier does, because that energy is much less concentrated at longer ranges.

Weapons
To find a weapon's Starship of the Line statistics, take any pre-existing High Guard design and 'spend' factors to increase the Acc, Pen, Dmg and RoF of that weapon's batteries. Four factor-5 laser batteries could look something like this (alternate configurations are possible):

Type: Beam Laser Weapon Name: GR-24 TL: 12 Mount: 4(4x3) Acc: 12 Pen: 4 Dmg: 2 RoF: 1 Dur:[2]1

In English, this means four batteries, each composed of 4 triple GR-24 beam laser turrets, each battery individually armoured to factor-2 with a durability of 1. (Some of these stats are purely for colour.)

For most beam weapons, the penetration modifier decreases as range increases by 2 per range band, and increases by 2 at close range. Energy weapons are the exception: their listed penetration modifier (usually negative) increases by 4 at close range, and they can't fire beyond short range.

Fixed mounts require the expenditure of maneuver Gs to be brought to bear. This means the player will have some difficult decisions to make beyond fight or flee: fire the spinal mounts, evade, or assume a helpful formation?

[Missiles are, of course, different. A close nuclear burst will have tremendous damage - comparable to a spinal mount - but because it is spread across a large surface area, it is compared to double the target's armour value. (This may have far-reaching consequences: a 20,000 ton freighter may be crippled or even destroyed by a single nuclear warhead.) X-ray laser warheads will hit the target with a moderate-damage laser with obscene penetration.]

[The RoF of missile batteries depends upon how much ammunition the player wants to spend - RoF 1 spends effectively no boxes of ammunition, RoF 2 spends one box, etc. (The theory is that any sufficiently large magazine is effectively of limitless capacity in a battle of finite duration, provided the captain uses missiles in moderate, non-fratricidal salvoes.)]

Hulls
A ship's hull will be listed something like this:

CL Distinction Hull: [4/2]19

where the two numbers in the brackets are front/flank (really, front and side/rear) armour and the ship's High Guard size code (used for computing critical threshold.)

Penetration
When a weapon hits a target and penetrates its defenses, compare the weapon's penetration modifier + damage to the appropriate armour rating.
* If the combined Pen + Dmg < armour, there is no penetration. (Surface damage is mostly ignored for purposes of the game.)
* If the combined Pen + Dmg > armour, a full penetration results. Roll on the ship's damage table to find out which type of system is hit.
* If the combined Pen + Dmg = armour, a partial penetration results. Roll on the ship's damage table, but the effective damage rating is reduced by 2, and there is no possibility of cascade damage.

If the remaining damage >= hull size + flank armour factor, a critical is scored. (Most criticals will disable a ship, and they should only happen in the case of an obvious mismatch.)

Each ship has its own damage table, rolled with 2 dice. The position of each system is calculated based on its relative size within the ship - the largest system goes in slot 7, the two next largest go in 6 and 8, etc. Turret weapons, bay weapons and hangars are then swapped one slot closer to 7, because they're on the outside of the ship, and thus more likely to be hit.

Once damage has penetrated the hull, it is considered to have Pen 0 no matter what its original penetration was. (It now consists of high-velocity shards of hull.) If it hits a system protected by its own armour, just follow the system above to determine if it penetrates to damage the system.

Damage Effects
When a system is hit, compare the damage to the durability:
* Damage < durability: The system is damaged and inoperable (i.e., it's repairable, but doesn't want to work.) For systems with multiple factors (e.g., jump drives and power plants), each factor is considered to be its own system.
* Damage >= durability + 4: The system is destroyed beyond repair; it must be replaced. Roll again on the ship's damage table for cascade damage.
* Otherwise: The system is destroyed. Do not continue with cascade damage.
* If the weapon also inflicts radiation damage (i.e., the Dmg score is appended with an asterisk) Crew hits are doubled, and any damage to a non-fiber-optic computer destroys that computer.

Cascade Damage
Cascade damage is the spinal mount's best friend. If the damage of a weapon is much higher than the durability of the system it hits, damage continues until the damage is absorbed by something or a blowthrough occurs.

[Blowthrough is mainly a play-balance handwave. I don't have a satisfactory blowthrough mechanism yet; I'd use hitting the same system type twice in a row, but this doesn't give light forces the benefit of any doubt.]

 

[rust]

Assume the two opposing sides are each arranged in groups of several ships ... , not exceeding the level of their admiral's Fleet Tactics skill.

This seems a bit too restrictive to me. I think an admiral should have the
chance to take some risks (or to overestimate his own abilities ...), but
should then be "punished" (through some modifier) for trying to command
more groups than his Fleet Tactics skill does enable him to control.

 

[dccarles]

This seems a bit too restrictive to me. I think an admiral should have the
chance to take some risks (or to overestimate his own abilities ...), but
should then be "punished" (through some modifier) for trying to command
more groups than his Fleet Tactics skill does enable him to control.

I agree with you. One formation a task force admiral can assume is Line Ahead, which lets him control more ships. A fleet admiral or task force admiral can also command more ships than his skill, but then is assumed to be dividing his attention, and so uses half his Int for initiative. (That, at least, is the plan.)

One thing I plan on doing is allowing each admiral to use his Fleet Tactics skill as a modifier to one task roll per turn. This represents where the admiral is putting his (or her) priorities. They only have so much situational awareness and a lot of information demanding their attention (even with a full staff), and I think one of the most important game decisions will be where best to place that attention.

--Devin

 

[rust]

One thing I plan on doing is allowing each admiral to use his Fleet Tactics skill as a modifier to one task roll per turn. This represents where the admiral is putting his (or her) priorities.

I think this is a very good idea.

I am more "at home" with land battles than naval battles, and there some of
the worst defeats were caused by the inability of commanders to recognize
in time on which part of the battlefield the decisive action took place.

The most successful commanders (like Wellington, who never was defeated)
had an almost incredible talent to be (or at least look) at the right place at
the right moment, and there to give the decisive orders.