[Rhodes22-list] Lightning mitigation

Sat Jul 14 13:14:08 EDT 2012

I believe in benjamin franklin's lightning dissipation theory.  Though recent studies have gone either way, for the lightning diversion theory to work the ground wire for a lightning rod would have to be solid copper 2 or more inches in diameter to keep from melting in a strike.  I think the cone of discharge helps prevent the strike and so do most ocean sailors.
Just my 2 cents.  Read up on it.  Pretty fascinating stuff.

On Jul 14, 2012, at 10:48 AM, Ronald Lipton <ronald.lipton at gmail.com> wrote:

> Grounding the mast will not protect you from a lightning strike and will increase the probability a bit. Grounding the mast will route the resulting kiloamps of current away from the electronics only if the conductor is thick enough. In general lightning protection for a small boat is probably not worth the effort, although case of a boat on a lift may be different since it is the tallest thing in the area. In general there is a concept called the circle of protection applied to lightning rods where drawing something like a 45° angle down to the ground gives you the area is protected by the rod.  that's also the area where lightning strike is likely to be attracted to a tall object. 
> 
> Ron
> 
> On Jul 14, 2012, at 8:58 AM, Goodness <spreadgoodnews at gmail.com> wrote:
> 
>> If your boat mast is grounded then a lightning strike to the mast is not really going to happen.  Many carry jumper cables and when a storm comes up clamps to a mast fitting and toss the other end overboard.  A more clever solution is an internal grounding wire to a metal underwater through hull......however that through hull needs to be protected with a zinc or it will corrode big time and sink you.  I have seen lightning switches that you flip in a storm too.  On a dock on a lift, it would be smart to ground the mast to the actual ground, very little corrosion risk there.
>> 
>> 
>> 
>> On Jul 14, 2012, at 12:51 AM, peter klappert <peterklappert at comcast.net> wrote:
>> 
>>> 
>>> Just to bring you all up to date and ask a question (or two).
>>> 
>>> Did I mention that the day I discovered the damage the Tampa Bay Times reported that Tampa has lost its (completely unofficial) status as lightning capital of the world?
>>> 
>>> I may as well get to the important question right away, then rattle on for anyone interested in the patient's health. So here's the question: 
>>> 
>>> What kind of lightning mitigation does the R22 have? For example, it might be heavy guage wire or cable connecting the shrouds to centerboard or some other metal below the waterline.
>>> 
>>> Does anyone know? Or has anyone done or modified this sort of thing on their boat?
>>> 
>>> Here's the latest news. If I had more time I could make this shorter, but it's past midnight and the marine electrician is due at 8 A.M.
>>> 
>>> The damage to Aeolia is, of course, more extensive than I knew when I sent the list under the subject "Major Electrical Problems." But it's not much more extensive, just quirky and seemingly patternless.
>>> 
>>> There is no visible damage to hull cabin or rigging, but most electronics are fried, as are running and anchor lights; the VHF aerial apparently got melted out of its mast-top mounting. So far wiring seems to be ok, with some fuses blown and some not. The outboard's electric starter is gone, but the motor starts manually and runs like a purring cat. Both main & Genoa look to be like new--I was concerned because of their proximity to metal. 
>>> 
>>> I'll know a lot more after this weekend and hope to have Aeolia out on Tampa Bay sometime next week.
>>> 
>>> The concensus among those I've talked to is that having the boat elevated on the lift and the aluminun lift itself increased likelihood of my boat being either struck or damaged by a strike nearby. Still, the total height of Aeolia on the lift, including 2-foot VHF aerial, is only about 36-37 feet above mean high tide. 
>>> 
>>> One leg of dock wiring is shorted, but that may be unrelated. Aeolia was not on shorepower at the time and the hull made no direct contact with metal--it was on the carpet-covered PT lumber of the lift bunks. Odds are that was part of the problem.
>>> 
>>> Obviously I need to make sure the lift is grounded (never thot to wonder or doubt it until this happened) and the guy who built the dock is looking into what might be possible and legal by way of a lightning rod on a pole. His power boat has a 24' metal antenna and has never been struck. My next door neighbor docked his C & C 34 behind his house for many years without incident. Lightning strikes--or damage, at least--among the big sailboats on the other size of Apollo Beach (in Bal Harbor) are reputed to be rare.
>>> 
>>> G'night!
>>> 
>>> 
>>> 
>>> 
>>> 
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