we have been hit twice in 4 years, once just before we bought. Last hit was July 5 in Muskegon Michigan. A direct hit vaporized the main mast Windex. We lost:
1.5 KW back-up alternator
3 of 6 spreader lights on two masts
all mast-head lights
all nav lights
all bow wiring was fused
3 LED bulbs in the bow cabin
transom paint was spauled
2.5 KW Xantrex off line (re-boot fixed it)
60 amp shore power breaker smoked
Curiously, the lightning arrestor was un-damaged
We have 60 cabin LED bulbs and 13 LED lights aloft. Even with all on at once, 0.4 amps. I haven't done the math but the diesel to charge & wear & tear on the batteries is the reason to have LEDs.
My observation: all lights, radio & any device should have its own local two-pole switch to interrupt totally both power & ground with an air gap. I installed our Simrad this way as well as its radar and depth scanner - no problems. This may not save everything every time but it is a definite preventative to induced spikes.