Robert replied to me: > > Bug or feature? A lightweight armor means more DR, even if it can > > burn, and a big HEAT warhead will ruin your day anyway. > > > This is actually a problem with the way GURPS handles damage to large > objects - HEAT rounds aren't very effective anti-shipping warheads. the > holes they make are small, and their energy will disperse quickly in the > outer compartments, so they wan't cause massive flooding, and they won't > reach the vitals. That's why most anti-ship missiles use various kinds > of semi-armour piercing warheads.
That was in reference to burning APC armor, which was in reference to burning ship armor. As far is GURPS is concerned, HEAT vs. APEX vs. SAPHE works out as desired -- HEAT is good for targets with a high DR compared to HP, while internal explosions from SAPHE are good for high HP compared to DR, and APEX falls in the middle. Considering how the fire rules don't work out, lots of raw damage is required to degrade HP, tens of tons of HE-style warheads. > > Are there any mistakes in my math or rules? It seems that > > Phalanx can handle somewhere around 0.4 missiles per turn > > per mount, which is a lot more than I'd expect. TL7 time > > on target attacks won't be synchronized to the second. > > > > Maths looks good, and the rules may or may not reflect operational > reality. I think I noticed an error, 28 - 19 = 9, but the effective +2 for burst fire should be on top of that. But then the big Soviet missiles like a Sunburn or Kitchen are faster, which makes them harder to hit and requires a longer engagement range, so at speed 3,000 it is -22 on the first firing turn and -21 on the second firing turn. That would give an effective roll of 8 on the first turn and 9 on the second turn, for a 90% kill chance with one mount firing six 20-round bursts. The decision to aim a second CIWS would have to be made before the outcome of the first firing turn is known, so it makes sense to distribute the mounts equally. If four mounts engage four time-on-target missiles, there is a 35% chance of at least one leaker. That assumes all four mounts can bear, or that there are even more mounts (four per broadside?). Now assume that a 40-missile salvo arrives in ten groups of four, three seconds apart. Not entirely realistic, but that is surely easier for the defense than a random distribution. There would be four hits on average, and a 99% chance of at least one leaker. So the outer defenses have to degrade the incoming salvo first. The point defense which can degrade that massive strike could easily deal with a handful Exocets/Harpoons from a destroyer or a flight of fighter-bombers, but other destroyer-class warships might have only one or two CIWS. > CIWS vs missile is not something that's ever been really tested > 'live'. However, the rate does seem high, given that ToT saturation > attacks were considered a major issue (and still are, I think). The defense has to be lucky every time, the attack just once. > I expect > that they overwhelm firecontrol and the ability of the gun to physically > move to the next target more than the rate at which it can shoot down a > target once it engages it. I was assuming one turn between engagements, and one computer and radar per mount. Target distribution between mounts could be another issue, with one missile being overkilled and the other going free. > Certainly ships' SAM systems were very > vulnerable to saturation (to the point where until the Aegis systems > entered service western navies really should have been mounting a lot > more medium calibre semi-automatic/automatic guns on their ships). Point defense can only defend point targets. The Aegis ships were supposed to defend battle groups. A high-end TL7 SAM could need a skill 21 or thereabouts SARH seeker to engage missiles at 50 miles, which means there is a 50% chance of lock-on. No missile lock means no launch, so only a second would be wasted. Once there is a lock, the missile probably hits. RoF is an issue for the older launchers, less so for VLS. _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
