Lightning Rod Sailboat

Are Sailboats lightning rods on the water?

I have 3 sailboats and two of them have been hit by lightning.  An aluminum mast with an antenna on top just pulls the lighting out of the sky. If you are out on the water the mast is the highest thing around, thus it is best target around. I think that the boat can build up a static charge with the Dacron sails flapping in the wind and this may add to its likelihood of being hit.

Electricity will flow to ground by the easiest route. It will go to ground by any way it can if there is not a good convenient path. When lightning hit my boat the first time, the tri-color light and antenna on the top of the mast just disappeared. The antenna wire down the inside of the mast melted, and the radio was fried. When I opened the radio case the electric components looked like burnt popcorn. My speed sensor was blown off the bottom of my boat. Almost all my fuses in the panel were open. I cannot remember if I had to replace the battery or not.

My boat was the only sailboat in the marina that afternoon when a sudden “sun shower” popped up. I was razzed that it was nice to have a lightning rod in the marina to protect the other boats. There was very little other damage I could find from the strike other than the electronics.  I ask around what I could do to prevent damage like this again and got no real positive feedback
.

One sailor that is an electrician by trade said that a boat is always grounded by the water. A clear easy path to the water is the best protection. A very simple way to create an easy path is to attach a piece of wire cable like what the shrouds are made of, to one of the shrouds and let it trail in the water. The electrician said that boat lighting rods were a waste of money, but could get one for me if I wanted one; this was accompanied with an evil smile. The quote: “a fool and his money are soon parted” was what came to mind seeing the smile.

Depending on the size of the boat and its construction, the boat may a grounding system in the boat that connects things like bronze through hull fittings, steering cables, and other metal parts all together to provide a ground to the boat and to the water. This gives a ground plane for some electronics as well as a ground for the boat.
 

My small sailboat has PVC through hulls and no internal motor and thus no ground plain in the hull. It does have a metal drop keel. The drop keel has a safety cable attached to it that moves up and down as the keel is raised and lowered. I figure it is there in case the strap winch fails. I attached a jumper wire between this cable and the mast mounting plate assembly. This gives a direct path to ground for my boat
.

Since the water you are floating on is ground and if you establish a ground line from the mast to the water the mast is the same potential as the water. When this is done the boat mast and water are of equal potential and there is now just a random chance that any point on the water has the same chance of being struck by lightning.

A wire cable to shroud and into the water is an easy and cheap way to add protection to your sailboat. It works as well as other thing you can do and it is cost effective. I have some old shroud cable and cable clamps that I can sell you for a lightning protection system if you need some (evil smile). Have a good sunny day. *-)