— July 2003
By Ben Ellison
Live Weather at Last
Relative to your
May column “Zap! Boom!” do you have any suggestions for protecting
those of us with steel hulls from lightning, or will our boats simply
serve to protect the nearby FRP and wood boats by involuntarily attracting
the lightning strike to our own boats? R.D., via e-mail
The crucial concept is that you cannot really shield any boat from a strike, but you can attempt to limit the damage it might inflict. The first defense is one or more “air terminals,” or lightning rods, as high above the boat as possible, connected via low-resistance conductor to some sort of ground plate on the hull bottom. That’s where you’re ahead of the game, as your entire hull bottom can act as a ground plate. The second defense is bonding your electronics into the protection system, and the third is to have a game plan for securing the boat and retiring to a neutral spot below if and when you find yourself in lightning. Overall, while strikes do act in notoriously erratic ways, they don’t hit boats all that often. Also, as I note in this month’s column, products are appearing that will let us track storm cells at a distance and thus possibly avoid them.
Finally, the fact that your bottom is an enormous ground plate does mean that an improperly designed lightning protection system could cause serious electrolysis problems. NMEA and ABYC are knowledgeable on these issues, and you shouldn’t have a system designed without the expertise of both organizations.—B.E.
Got a marine electronics question? Write to Electronics Q&A, Power & Motoryach, 260 Madison Ave., 8th Fl., New York, NY 10016. Fax: (917) 256-2282. e-mail: PMYElectronics@primediamags.com. No phone calls please.
This article originally appeared in the June 2003 issue of Power & Motoryacht magazine.