[Rhodes22-list] lightning protection

[Chelle or Bob Ginsburg]

FWIW, many, many years ago I worked on packaging for aircraft control electronics.  As you would guess, the electronics are redundant systems.  Even so, they are surge protected by current limiting resistors. 
Lightning strikes on aircraft do occur, but the consequences don't get much notice.  I hope this is because the surge protection and redundancy work.
A cursory look at my USBoat / West Marine catalog doesn't show any item I recognize as a surge protector for boat applications.
Maybe the incidence of lightning strike is so low that no one has thought to use a relatively inexpensive protective device.  
Surge protection could be independent of grounding.
The equivalent for domestic protection on standard 60 HZ is widely available at Home Depot and all hardware stores.

Bob G