Point taken.
But on the other hand, would scattering a half dozen fragmentation hand grenades in seperate locations in the vicinity of a tank really crack that tank like an egg, as these rules suggest? I'd like to find to find a middle ground for game balance purposes.
Now that I think of it, there are already rules for combining multiple explosives... which work entirely differently from the overlapping explosions rules. According to RAW, those 1,000 separate 1kg C4 charges would be fifteen times as powerful as a single 1 tonne C4 charge (1 + 999 / 2 = 500.5 as opposed to square root of 1000 = 31.62).
...times like this I really miss the explicitly-logarithmic damage of Star Wars Saga Edition, where double the *BOOM* always meant +1 die of damage.
It's a case of one size not fitting all. The rules make sense for everything
but frag grenades, really, since the "shredding" effect of the criss-crossing shockwaves really will do much more damage than one, bigger kaboom hitting at the same spot... although, really, the 501 vs 32 just demonstrates the how nerf the "charge scaling" rules are.
As a fix, since it makes no mention one way or the other of how you modify the AP when using the Overlapping Explosions rules, I'd take the route of assuming that the AP of the Overlapping Explosions rule also adds the same way. AP of the best single hit + half of the total of the rest.
In that case, those frag grenades are at AP +5 per grenade. That gives them a final AP of +18... which, of course, adds to the Vehicle Armor. That means, assuming the worst case scenario of them all landing with zero scatter, it would only need 24 points of armor to defeat the grenades' collective DV 42... easily doable for even a modded street vehicle that's been upgraded with Smart Armor.
Of all the vehicles in Chummer marked as a "Tank" of some sort, none of the ones marked as "Battle Tanks"... the equivalent of a modern M1 Abrams... fail to rise
well above that mark, and the ones that
would be vulnerable to such a strike are all fluffed as lightly armored, due either to a desire for speed or because they're "cheap"... and the weakest still rolls 55 dice to resist after the +18 is added in.
And, again, that's pretty much assuming zilch scatter on all the detonations. That means the grenades have landed on and under the tank, where they stand the best chance of damaging the treads or bouncing just right and managing to detonate in part of the engine's intake/exhaust system. Every meter of scatter off the primary detonation, or 2 collective meters of scatter off the supplementary explosions, drops the DV by 1 while the +18 AP stays the same, meaning an inaccurate barrage would quickly become worthless.
--- --- ---
Of course, talking about actual
explosives doesn't really cover the effects of White Phosphorous Grenades, which fill the area with a load of ultra-hot incendiary particles that are more than capable of melting through steel and similar materials. Douse a tank with enough of the stuff and you'll end up with all sorts of nasty problems like tank shells cooking off, fuel-cells exploding, and the crew getting dry-roasted and/or burned alive.
Here is a link from LiveLeak showing a real WP rocket hitting a real tank. The WP grenades may not be armor-piercing rockets, but I definitely think a full-scale barrage of them would make up for it with saturation.