The behavior of lightning is very tricky to predict. Just being in the vicinity of a strike can do you harm due to the inductive nature of the massive increase and then decrease in current. It throws out a magnetic field that can induce current in near by objects. A few years ago, a fiberglass boat trolling off the Pink Hotel in Long Beach got struck. It hit the VHF antenna. It looked like it was blown apart with a cherry bomb. All the electronics, not just the radio were fried and the engine wouldn't start. They towed it to my marina to fix the outboard. The guy fishing was fine.
I saw a buoy get hit in Jones inlet. Grounded right through the chain holding it to the bottom. I guarantee the electricity will find a bronze through hull and use that as a path into the water. Lightning strikes trees and we think of wood as a pretty good insulator. Air is an insulator and lightning passes through 10000 feet of it to get to the ground. A few feet of fiberglass will conduct electricity at that voltage with no problem.
Fiberglass will not conduct electricity I don't care how much the voltage is, it's all based on how many valence electrons in the outer shell of the material, copper has 2 valence electrons making it an excellent conductor, silicone has 4 valence electrons, making it a good semiconductor, fiberglass and porcelain have 8 valence electrons, making them excellent insulators, hence why most insulators for High voltage are made of porcelain or rubber coated fiberglass, when lightning strikes an object like an radio antenna, the voltage/current goes up exponentially because it has a small pipe to travel through, that's why most antenna explode when hit, the dissipation of a lightning strike depends on the object that has been struck to dissipate high current, with fiberglass boats, when struck, the electromotive force (current) is so powerful that it will run across the surface looking for a place to ground itself leading some people to believe that their fiberglass boat can conduct electricity.
I have personally been involved with several lightning strikes, and not one did the same thing twice.
Unpredictable at best, I saw it strike a catenary while working for Metro North on the south side and shoot across and hit the north side where 8 guys were just finishing up and aerial ground, they were surrounded by an orange aura of electricity, only one guy was affected, the guy holding the aerial ground wire, his hands were slightly burned.
Again while working for Metro North, lightning struck the trolly wire we were working on, we had 2 grounds on and the lightning traveled down the wire like a bright light, at first we thought there was another train on our track, when the light got to the ground sticks that's when the fun started, it dissipated right through the ground sticks and encompassed the tower car we were standing on, it traveled down the car and right into the rails, sparks flying everywhere.
Best thing to do is not be in the path, if your on the water caught in a lightning storm, drop all your antennas, leave your outriggers up if you have them, they give you a better cone of protection, if possible slide in next to a vessel that's bigger than yours, I did that when I was caught in thunderstorm while fishing the sound, I got right up next to the Port Jeff ferry, giving me a nice cone of protection, the storm moved off and I headed for the barn.
Be safe.
