lightning strike

[Robert Tuten]

Two days ago, my next door slip neighbor, a retired doctor in is seventies, was aboard his Beneteau 38 preparing for a Fourth of July cruise when lightning stuck his boat. He was docked in his slip in a marina with about 200 sailboats. The boat was attached to shore power. All his electronics were fried. The electrical system is questionable too. The alternator is charging, but at maximum rate. We presume the voltage regulator is shot. When we were able to crank the engine, the raw water cooling system wasn't circulating water. There is a golfball-sized hole on the port side of the hull just inches above the waterline and a similar hole in the cabin top below the mast.My neighbor told me that this is the second time the boat has been hit by lightning in the past 12 months. There was only electrical damage last time. He has some questions about lightning and boats so he is with me as we write this.Are some boats prone to attract lightning strikes? Has anyone else experienced a lightning strike? What other damage should he check for? Is there some way to deter another lightning strike?Fortunately, no opne was injured and my neighbor was able to get the boat yard to haul the boat first thing this morning for repairs. We'll see how it goes.

 

[steven f.]

shore power

I've posted questions about lightning strikes in the past. I'm wondering if both times the boat was plugged into shore power or just the last time. I too have a friend who's boat was recently hit and it was also plugged in. My question is this; do boats get hit by lightning more often if they are attached to shore power/cable/telephone or if not? To answer your original question, I've heard of boats being hit several times while the boats next door do not. Seems to be just a crap shoot so far.

 

[John Holroyd]

Surviving a lghtning strike

Lightning does not strike at random though it may seem so. It picks the shortest path to ground. That is electrically the shortest path to ground which may be different from the geometric shortest path. It is attracted to tall pointed things such as towers, trees or masts especially if they have a pointed top. The holes in the hull were most probably caused by moisture between the inner and outer skins turning instantly to steam and causing the hull to explode in these areas.You can provide a good deal of protection by making an easy path to ground for the lightning bolt. This could be done by electrically bonding the mast and rigging to the keel. Some sailors connect a heavy cable to the rigging and to a large copper plate dropped in the water for protection during storms. Whatever you use make sure it is HEAVY duty. A flat copper bar one inch by one eighth would not be going overboard.You can not prevent your boat from being hit by lightning but you can minimize damage by good grounding.The shore cable could be a factor. If the power lines are struck close to the boat you could get damage from that but it is unlikely to punch holes in the hull. Email if you have specific questions.Good luck and good sailing.