Lightning

[barnakiel]

Divide the storm area by your decks area and you get the chances. Probably one in a million, but how does it count, given the possible damage?

There will be damage. Up to the risk of sinking the ship.

You see a thunderstorm, sail around it, while you can.

If you cannot, sit down, away from all conductors, and pray.

If not religious, buy various thunderstorm prevention/mitigation systems.

b.

[osirissail]

This "Siedarc" system seems to be designed to specifically address the "side-arcing" that occurs with a lightning strike. Although the bulk of the energy most likely passes directly through your mast to your lightning ground system underwater, there is a large enough "side-charge" or the part that makes the "blue corona" hanging around to do havoc to your sensitive electronics.
- - The blowing holes in the side of the hull is most likely due to the energy heating defects or trapped water in the composite and it blowing a hole. But anyway the "spark-gap" design of the Siedarc is, according to the literature, supposed to allow a path for the residual energy to jump to the sea water's surface. Very interesting. . .