Aluminium Mast - Lightning Rod, Benefits?

[GordMay]

Sorry; my NWS probability citation is only applicable to the “general” population, not boats.

Excerpted from: Press release “Seaworthy Magazine looks at 5 shocking years of lightning strike claims data”:
http://www.bymnews.com/new/index2.ph...pdf=1&id=15803

BoatUS reports* that in any one year the odds of your boat being struck by lightning is about 1.2 in 1,000 (or about 0.12%), with 33% of all lightning claims coming from the State of Florida. The second most struck area in the country was the Chesapeake Bay region (29%), while on the opposite side, 13 states had no lightning-related claims, including states such as Idaho and Nebraska.

The rate of lightning strikes for sailboats was about four boats per 1,000, while motorboats averaged 0.5 per 1,000.

A surprise finding was that multi-hulled sailboats were struck more than twice as often as monohulls.

Interestingly, the files also showed that many boats equipped with lightning dissipaters were also hit, questioning their effectiveness. Most electronics aboard a boat were found not damaged by a direct hit but rather from surging electrical current created in the wiring by the strike.

* Source: "Lightning! Flash, BANG! Your Boat's Been Hit-Now What?," ~ by Chuck Fort
July 2005 issue of Seaworthy magazine

What are the Chances of Lightning Striking Your Boat?
Excerpted from: “Understanding Lightning Protection” ~ by Bill Laudeman
BoatUS.com - Seaworthy Magazine

The following statistics are based on all of the BoatUS Marine Insurance claims for lightning damage over a five-year period. The percentages suggest the chances of the various types of boats being struck in any given year.
Auxiliary Sail .6% Six out of 1000
Multi-hull sail .5% Five out of 1000
Trawlers .3% Three out of 1000
Sail Only .2% Two out of 1000
Cruisers .1% One out of 1000
Runabouts .02% Two out of 10,000

See also: “Thunderstorms -A Few Members' Accounts”
BoatUS.com - Seaworthy Magazine

[Lancerbye]

So if I stay out of Florida (too crowded anyway) andChesapeake Bay (wasn't planning on going there) Have a mono, do a daily ritual based on some tribal dance to chase away evil spirits like lightning protection system salesmen, I should be ok. Oh ya and don't go out on Friday the 13th. That's just asking for it.

As to my earlier remark about dinosaurs, they taste just like chicken. LOL

[MidLandOne]

Originally Posted by Lancerbye

...do a daily ritual based on some tribal dance to chase away evil spirits like lightning protection system salesmen, I should be ok. Oh ya and don't go out on Friday the 13th. That's just asking for it.

We make a point of not sailing under ladders and have never been struck by lightning so that works too .

More to this than meets the eys cos we have a black cat and whenever he comes cruising with us we get rough weather .

[Pauls]

Interesting posts, and some very good info. I experienced a lightning strike on a boat I used to have. Sea Runner was a 38', plywood with glass over powerboat. She had a short wood mast topped with a 3' long, 1/4" diameter brass lightning rod. The rod tip was pointed. The rod was connected to a 10 or 12 ga multistrand wire (don't remember which) which ran straight down from the mast to a 1' square copper plate mounted on the bottom of the hull. When I built her in the 70's this was a standard spec set up.

One day, doing inspections, I found that the multistrand wire, immediately above the copper post that ran thru the hull to the grounding plate, was totally burned away for a short distance above the post. It had obviously taken a strike and done its job, as there was no damage on the boat.

Note - current literature will tell you to use a wire of much heavier gauge. My experience certainly supports this.

Regards, Paul

[Roy M]

I'm installing a Strikeshield system next week on a Catana 431. The owner will be heading south from San Diego, afterward. He will, undoubtedly, inform me if anything untoward happens to him, and I'll pass along the info. I'll forward some pics when I take them.

[Tropic Cat]

Originally Posted by GordMay

According to some web-humourist:
Odds of being the victim of serious crime in your lifetime: 20 to 1
Odds of being murdered: 18,000 to 1
Odds of being struck by lightning: 576,000 to 1
Odds of winning a lottery 1,000,000 to 1
Odds of being killed by lightning: 2,320,000 to 1

So I should start buying lottery tickets?

As far as lightning protection goes, I too have done a lot of research. Unfortunately, I did it after taking a lightning hit to the top of the mast. (that was a very expensive day) What I found was that to properly rig the boat to dissipate that much energy would make the boat look like something I wouldn't want to own.

It's better to buy a boat that dissapates the energy adequately as part of the boat's design. Lot's of metal stays and a diesel with a propeller shaft. Oh, and no metal thru hulls.

Also, minimal electronics on board. Anything connected to boat wiring will have to be replaced after a lightning strike.