The problem with lightning
is the range of voltage, hence damage, can be from 10v to 10,000,000v (or higher).
arrestors help on the lower voltages strikes (or side flashes), but a direct strike with millions of volts of potential will burn anything in it's path. There is no failsafe protection from lightning, it's simply too variable. Statistically, using arrestors and mechanisms to help get the bulk of the current
off the boat in a direct path has helped, but it's very hard to measure the level of 'help' with the variability between the power of each lightning strike.
A common belief is to provide a direct and short path from the mast
to the water
. The goal is to get as much of the current
off the boat quickly. It's generally accepted that you'll lose the electronics
, but the goal is to save the fiberglass
. Lightning will follow the fiberglass
if that's the only way to ground, when it does this, it can burn open cracks of 2" or more. Not good when that happens below the waterline.