Point Defence on a Dreadnought Battlesuit

[scc]

Originally Posted by vicky_molokh

Depends on what you're armed with. If the targets are clearly hittable, and the PD damage is enough to harm them, shooting immediately is the way to go.
If they're too tough, and the launchers themselves are protected except when actively launching, then it's a better idea to track as many targets as you have Enhanced Tracking + 1, with Opportunity Fire (Wait/Aim), and shoot as they launch, keeping Acc.

Did you mean Passive Defense or Point Defense here?

[McAllister]

Originally Posted by scc

Did you mean Passive Defense or Point Defense here?

Point defense.

[Mailanka]

Originally Posted by vierasmarius

For mounting the laser, you could use Shoulder Servomount (UT151). As for operating it, for simplicity's sake I'd assign it a "Parry" score rather than making every Point Defense attempt its own attack. Larger missiles would be easier to hit, but would also require more damage to disable, so I'd call that even and not assign modifiers for missile size. More advanced missiles would be faster or more evasive, so would have a penalty. Likewise, missiles fired at close range (or which pop up over cover) would be harder to intercept.

I'd actually handle ECM the same way, as a "Block" score modified by the sophistication of the missile's electronics. Of course, none of these stats exist yet. I'd be curious to see what results you folks get from intercepting missiles "manually", as a benchmark for the difficulty of these defense rolls.

This is nearly word-for-word how I would handle it.

[The_Ryujin]

Originally Posted by vicky_molokh

You can probably find a weapon mount/arm somewhere. Then stick an AI into the computer that will have access to the arm. Then use the Wait rules. Which, of course, will give you bad chances unless you know whom you are Waiting against - better detect those missile launchers, and have enough levels of Enhanced Tracking. Shooting down missiles on a millisecond's notice is hard.

Bad chance or not, having an AI use a wait maneuver "against any missiles that enter range" to try and shoot down a missile as far away as possible is pretty much how point defense works in real life and the last time I check the statistics (which to be fair was over a decade ago) the Phalanx system has had a 0% success rate against missiles in real combat situations and mind you these were all sub sonic anti shipping missiles like the Exocet if I recall correctly just to give you an idea.

Though as a GM I would let a point defense set to act as a "parry" as a last resort but keep in mind that means the missile explodes pretty much on top of you...

[johndallman]

Originally Posted by The_Ryujin

... last time I check the statistics (which to be fair was over a decade ago) the Phalanx system has had a 0% success rate against missiles in real combat situations...

Land-based Phalanx appears to have had successes against mortar rounds, which are much easier targets. It's not clear that it's had any engagements against missiles, apart from the 1991 Silkworm incident, when it did fail.

[Rysith]

What about the Area Defense perk from Gun-fu p.17? That provides a parry roll at -15 base for speed/size, and while it's noted as highly cinematic it seems more like it's highly cinematic _for humans_, and much more reasonable for an AI-controlled laser with ETS and targeting/stabilization software shooting down larger projectiles.

As a side note, assuming a skill-16 AI with ETS and an acc-12 laser gives you an area parry of (16/2 + 3 -15 +6 + 12) = 14, which seems quite decent.

[The_Ryujin]

Originally Posted by johndallman

Land-based Phalanx appears to have had successes against mortar rounds, which are much easier targets. It's not clear that it's had any engagements against missiles, apart from the 1991 Silkworm incident, when it did fail.

There are a few more instances including an Israeli ship in 2006 if I recall. I use to have some research collected on this subject that I came across while working on gun rules for a home brew RPG I worked on before happening upon GURPS but the HD I had the files on has long since bit the big one. But for the most part what I remember is that in practical combat situations having only 1 or 2 CIWS on a ship did not give adequate protection to a ship when quick response times were required (mind you in situations where there more then on ship or they had time to track the missile longer the numbers would probably be better, also some ships do have some serious coverage problems). Also in hindsight it showed how realistic giving +4 situational bonuses to closed test firing really is given how much better the system works during tests heh.

Of course by TL 11 this technology is gonna be just a bit more capable, even if Transhuman Space style SAIs don't pan out just having access to compacted lasers and hyper-velocity rail guns will make for far better interception tech.

[vicky_molokh]

Originally Posted by Rysith

What about the Area Defense perk from Gun-fu p.17? That provides a parry roll at -15 base for speed/size, and while it's noted as highly cinematic it seems more like it's highly cinematic _for humans_, and much more reasonable for an AI-controlled laser with ETS and targeting/stabilization software shooting down larger projectiles.

As a side note, assuming a skill-16 AI with ETS and an acc-12 laser gives you an area parry of (16/2 + 3 -15 +6 + 12) = 14, which seems quite decent.

Acc only helps if you are a Gunslinger. And that is a Cinematic trait. (ETS is much more reasonable for an AI.)

[McAllister]

Originally Posted by johndallman

Land-based Phalanx appears to have had successes against mortar rounds, which are much easier targets. It's not clear that it's had any engagements against missiles, apart from the 1991 Silkworm incident, when it did fail.

In its defense, in the 1991 Silkworm incident, it appears to have decided to defend the ship from its own chaff, and then the Silkworm missile was destroyed by another missile... hard to say if it would've worked if the IFF had been better.

[McAllister]

Originally Posted by vicky_molokh

Acc only helps if you are a Gunslinger. And that is a Cinematic trait. (ETS is much more reasonable for an AI.)

It looks like this is what I'd want my point defense system to have.

• Enhanced Time Sense [45]
• Altered Time Rate (Wait: Aim and Wait: Attack only) [?]
• (Optional) Enhanced Tracking X [5X]
• (Optional) Scanning Sense with Targeting [Varies]

Enhanced Tracking seems unnecessary, as it would be impressive enough if a point defense weapon could reliably fend off one threat per second, let alone multiple.

The question is, is there a better way to try to Aim at incoming missiles before shooting them? I don't like the idea of giving Gunslinger to an AI, but if we could extract "All Attacks have the Aim bonus," that would seem to work. Should the AI simply Aim at missile on the first second of their approach, and accept that it has to make snap shots against missiles that would reach it within a second?