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Old 04-15-2018, 07:00 AM   #25
weby
 
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Join Date: Oct 2008
Default Re: [Spaceships] Missile shield vs. ramming: two questions

First: Gurps HP rules are broken for large structures/vehicles. They are much harder to destroy than the cube root gives.

And related: In spaceships the beam weapon damage scales with cube root too to keep the damage scaling same as HP, but missiles and ramming do not.

The simple solution to that is: Use square root for both damage and object hitpoints. Square root is closer to real effect. This will both make beam weapons more effective against smaller targets and make larger targets tougher.

The damage square root is proposed in "The Square Root of Destruction" pyramid 3-34 page 9.

Second: Kinetic weapons are more effective due to the ability to get high speeds at higher TLs. This one is realistic but can be unsatisfying if you want large ships to survive.

The easiest solution to that is to use super science in the form of Force Screens that are silly good against kinetic threats. As example Vorsigan saga gives their Force Screens half normal dDR vs beams but fifty times normal dDR vs kinetics(so 100 times better than vs beams).

Alternative solutions include allowing smaller batteries on larger ships and not use rapid fire rules for massed batteries. Combining this with tactical combat where you have time to attack the incoming missile multiple times.

As example at TL 10, you cannot have more than DR 30 hardened as front armor and with The Square Root of Destruction a 30mj laser with 2d*10 will penetrate it easily. The battery weights 15 tons and needs 7.5 tons fusion power plant, so by using 2.25 times the drone mass(and remember that the attacker will likely use 1 2/3 times the mass to include the vehicle bays) you will get quite many shots at the drones(20+), with likely 2-3 hits needed to neutralize. So having say 1/4 the number of expected drones in defensive weapons should be enough. Under this system the automatic misses do not matter as you get so many attacks.

Alternative to beam weapon based defense is to use massed small missiles. Even a small missile will do devastating damage. Use massed Striker Missiles (UT 168) as a last ditch defense. No small target cannot have the armor to stop a 100mm High Explosive Multi-Purpose round with an effective dDR penetration of 126 against a hardened armor target(252 normal) and the missile weights only 17 lb and is a smart weapon so is independently targeting and make separate attack rolls. So launching 2 000(17 tons) to counter a 100 drone attack(1000 tons) is definitely feasible close defense. That gives 20 tries for each incoming drone by using a minimal part of the drone mass(1.7%).
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GURPS spaceship unofficial errata and thoughts: https://gsuc.roto.nu/
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