How big a crater would a NGauss, NPPC, or other naval weapon, even the centerline mass drivers, make as ortillery?
Depth and width, thinking of a new map and what results of 1&2 SW bombardments
If you use Terrain Factor (p.62 TO AR) then every 200 damage drops the level by 1 and adds Rough if it doesn't have it already.
A Heavy N-Gauss does 300 damage to its center hex, so will drop terrain by 1 hex there.
One hex away, the damage is 0.8 x 300, so 240, still enough.
Two hexes away, the damage is 0.6 x 300, so 180, no longer enough to drop, but close.
So a Heavy N-Gauss creates a crater 3 hexes wide.
A Heavy Mass Driver is 1400 damage. It will make a crater that's 11 hexes wide, and 7 levels deep at the center.