How many Ravens (assume L4 or L5 skills) would it take to pop a freighter in one volly, in highsec?
Ro'Kera
I did some quick calculations, just for fun.
A Fenrir piloted by a minimally skilled pilot is weakest against pure Explosive, where it has 152,222EHP.
A Raven with Level 5 skills in EVERYTHING can fit a Raven for up to 7,133HP per volley: 6x Siege Launcher II, Bane Rage Torpedo 5x Estamel's Modified BCS 1x Large Warhead Calefaction Catalyst
Divide 152,222 by 7,133 and you get 21.3 -- so under absolute best conditions, you'll need at least 22 uber-gank-fit Ravens. If you just go with BCS IIs, your volley damage drops to 6,640. That means you'll need another Raven, so 23.
Then account for less-than-perfect Raven pilots, a less-than basic freighter pilot, and a little extra "to be safe," you'll need somewhere in the neighborhood of 30-40 gankers.
Probably not a good investment. :)

I should have added t1 fit insurance suicide. Also remembr, in .5 you’ll get 2-3 volleys off so less there. :-D