Ramming

[Brandon C]

I thought I'd split this off on it's own thread.

In the course of dealing with the frac-c impactor issue, let's not forget normal battle speed ships ramming ships/stations.

Although, oddly, of the four versions of Traveller I have (CT, MT, GT, MgT), only GT deals with ship collisions*

I would be inclined to treat a ramming ship as a missile, although it would take a great deal more than one laser hit to stop it. Unless the M- drive or powerplant was rendered incapable of maneuvering for an attack, the final resolution should involve the agility and Pilot (or Small Craft) ratings of both ships. Not sure about damage yet.

* there might be something in MgT:HG I missed

 

[Timerover51]

I thought I'd split this off on it's own thread.



Although, oddly, of the four versions of Traveller I have (CT, MT, GT, MgT), only GT deals with ship collisions*

I would be inclined to treat a ramming ship as a missile, although it would take a great deal more than one laser hit to stop it. Unless the M- drive or powerplant was rendered incapable of maneuvering for an attack, the final resolution should involve the agility and Pilot (or Small Craft) ratings of both ships. Not sure about damage yet.

* there might be something in MgT:HG I missed

Considering how difficult it was for one nautical ship to ram another deliberately, I would view the likelihood of a successful ramming attack by one starship against another as somewhere between nil and non-existent.

 

[kilemall]

well darn it, coulda posted my rules!

 

[mike wightman]

Post them anyway - I like to see new rules and how others do stuff.

 

[Brandon C]

Considering how difficult it was for one nautical ship to ram another deliberately, I would view the likelihood of a successful ramming attack by one starship against another as somewhere between nil and non-existent.

Ramming is just a high speed version of general collision rules, which most editions don't cover either. Collisions, though, are the result if failed rolls (badly failed for some editions) all around.

 

[ShawnDriscoll]

I've only used critical rolls to see which ramming ships get what damages to them.

 

[Ulsyus]

I would be inclined to treat a ramming ship as a missile, although it would take a great deal more than one laser hit to stop it. Unless the M- drive or powerplant was rendered incapable of maneuvering for an attack, the final resolution should involve the agility and Pilot (or Small Craft) ratings of both ships. Not sure about damage yet.

If the target vessel wasn't changing it's vector at all, then it'd just be a matter of doing the maths and having sufficient velocity in the sacrificial vessel.

If the target vessel is under power, then the aggressor would need a lot of g's/agility to be able to continually adjust their own to maintain aim. At that oint the proverbial camel through the eye of a needle may be a pretty simple problem in comparison.

 

[aramis]

If the target vessel wasn't changing it's vector at all, then it'd just be a matter of doing the maths and having sufficient velocity in the sacrificial vessel.

If the target vessel is under power, then the aggressor would need a lot of g's/agility to be able to continually adjust their own to maintain aim. At that oint the proverbial camel through the eye of a needle may be a pretty simple problem in comparison.

Even if it's under power, the potential position change is a function of acceleration and distance. As the ships close, positional uncertainty reduces drastically.

It's all the same math as missile interceptors in air. ANd those missiles have good hit rates

 

[Carlobrand]

Given the similarities, I'd agree with treating it as a missile attack - maybe factor-1 with the usual modifiers.

Where the devil hides is in figuring out damage. The range of possibilities ranges from ships of about the same mass to a little unarmored 10 dT fighter ramming a million dT armored dreadnought.

 

[kilemall]

Post them anyway - I like to see new rules and how others do stuff.

Well my players don't usually look to do this sort of thing, so I just came up with a quick version I might resolve it by, more as a starting talking point then anything else.

[FONT=arial,helvetica]Try this quick resolution I just made up on for size-

In CT/HG terms, I'd say target roll is 10+ with the following DMs-

+ rammer agility & pilot skill

- target agility & pilot skill

+/- target ship size DM

Phasing is during movement, attack can only occur at short range and the rammer having higher agility.

Target ship gets a free round of firing against the incoming rammer(s), and fires only against ships that succeed in the above to-hit roll. If the ramming ship is destroyed or loses agility to hit, the rammer 'misses'.

Damage is 1 hit per 100 tons of rammer ship tonnage at spinal/nuclear weapon rolls (no +6 DM), x (rammer agility-target agility if higher then one). IF the target and the rammer are ramming each other, add both agility scores and multiply against the tonnage hits.

So a Type S at max agility 2 against an agility 0 target would generate 2 spinal hits.

If there is some question as to whether the rammer would survive such an impact, treat the rammer as having damage inflicted as though the target ship rammed them, with the same agility multiplier.[/FONT]

 

[Carlobrand]

...
Damage is 1 hit per 100 tons of rammer ship tonnage at spinal/nuclear weapon rolls (no +6 DM), x (rammer agility-target agility if higher then one). IF the target and the rammer are ramming each other, add both agility scores and multiply against the tonnage hits.
...

Given the kinetic energy formula, you might consider squaring the (rammer agility-target agility) part of the equation.

 

[Brandon C]

Damage is 1 hit per 100 tons of rammer ship tonnage at spinal/nuclear weapon rolls (no +6 DM), x (rammer agility-target agility if higher then one). IF the target and the rammer are ramming each other, add both agility scores and multiply against the tonnage hits.

What about small craft? Do they not do any damage? For example, a 10 ton fighter ramming a 400 ton patrol cruiser.

 

[kilemall]

Given the kinetic energy formula, you might consider squaring the (rammer agility-target agility) part of the equation.

Well, maybe, but I'm looking at this more through game needs then sim.

Since HG is so abstract, can't really do a proper velocity kinetic calc anyway.

 

[kilemall]

What about small craft? Do they not do any damage? For example, a 10 ton fighter ramming a 400 ton patrol cruiser.

Hmm, perhaps alter it to per 100 round down, so say a 10 ton fighter agility 6 hits an agility 2 target ship, that's 1 x 4 for 4 hits.

That's like getting hit with a surface impact spinal hit of D.

 

[Carlobrand]

You've given a way to generate a number of hits based on size. You didn't mention anything about armor. A TL 15 fully armored ship, if you go by the rules as written, is going to modify the roll well down the damage chart, taking at best some weapon and fuel damage and sometimes taking no damage.

However, you're dealing with impact energy at a level that's going to make armor pretty much useless. Impact velocities are going to be in the tens of kilometers per second at worst and in the hundreds at best. Your scout hits with kinetic energy in the terajoules to hundreds of terajoules, at velocities that render mechanical forces irrelevant: armor at the point of impact simply vaporizes - as does the forward end of the scout. The scout/superheated-plasma mass just keeps moving through the ship, vaporizing more mass, vaporizing more of the scout, shoving that out of the way, decelerating as it spends energy, but even on something as big as a dreadnought it goes out the other side of the ship in a small fraction of a second, before the now-plasmafied scout can even begin expanding significantly. My best guess is it looks a bit like this:

http://americanart.si.edu/collections/search/artwork/?id=32694

except that the bullet would be a glowing mass of plasma.

If the target is big enough relative to the impacting ship, it could survive with only that scout-size hole through it. Well, a bigger-than-scout-size hole, but nonetheless.

My thought is that armor is irrelevant at this level of impact. All the damage rolls need to be straight unmodified rolls.

 

[BlackBat242]

Yep - that's how I would handle it!

 

[vegas]

Even if it's under power, the potential position change is a function of acceleration and distance. As the ships close, positional uncertainty reduces drastically.

It's all the same math as missile interceptors in air. ANd those missiles have good hit rates

Right, but those missiles in the air are much faster and can pull far more Gs than their target and can still be evaded. It is going to be a lot harder for a ship-as-rammer to intercept a target with comparable M-drives. Not sure how to model it, but an evading target will be tough to hit.

 

[Carlobrand]

Right, but those missiles in the air are much faster and can pull far more Gs than their target and can still be evaded. It is going to be a lot harder for a ship-as-rammer to intercept a target with comparable M-drives. Not sure how to model it, but an evading target will be tough to hit.

I'm not an expert on missile stuff, but I was under the impression that most of the evasion techniques involved taking advantage of some weakness in the missile rather than in outmaneuvering it per se. For example, fighter aircraft take advantage of wing surface to alter their course more sharply than a missile can manage using its thrust.

https://defenseissues.net/2013/08/17/evading-air-to-air-missile/

In the spacecraft ramming scenario, there is no air and both craft are using the same method of propulsion. The only things I can see that would make a difference are the actual thrust being put out and the mass of the target versus the mass of the chase craft. Thrust being equal, and starting from the same vector, no one's hitting anyone. With a thrust advantage, the more nimble craft should have no trouble impacting the less nimble craft. Things get less clear when a craft has a thrust advantage but is less nimble than its target.

 

[vegas]

[1] Thrust being equal, and starting from the same vector, no one's hitting anyone. [2] With a thrust advantage, the more nimble craft should have no trouble impacting the less nimble craft. [3] Things get less clear when a craft has a thrust advantage but is less nimble than its target.

I broke your conclusion into 3 cases. [1] and [3] we agree. [2] I don't think is right, (but I can't prove it). The article you linked to however does describe the evasion I have in mind:

Once missile gets closer, aircraft will make a hard turn in opposite direction; if missile follows, aircraft will immediately reverse the turn. As there is a lag between aircraft changing the direction and missile following (for several reasons, most important of which is missile’s inertia), this will cause missile to head in wrong direction until it manages to correct.... Eventually, it will fly past the aircraft and miss.

Even if the missile/ramming ship has a speed advantage, I don't think that alone isn't enough to guarantee that you can make hi-speed contact. (If speed at impact in not a concern, then yes, I think [2] is probably true.)

It is obviously easier to chase a slower target down from behind, (though your energy on impact will be substantially less) than trying to intercept head on. (If you have enough time, you can turn around and try again if you miss.)

 

[aramis]

Right, but those missiles in the air are much faster and can pull far more Gs than their target and can still be evaded. It is going to be a lot harder for a ship-as-rammer to intercept a target with comparable M-drives. Not sure how to model it, but an evading target will be tough to hit.

You're thinking AAM's. I'm talking anti-missile missiles. AAM's have ≥90% published hit rates. AMM's only in the 70's, and are targeting those AAM's and AGMs... duels at 15+ G's. Each.