[Alberg30] Lightning protection
gord at transatmarine.com
Fri Mar 15 05:35:51 PST 2002
Re: [Alberg30] Lightning protectionI worry a fair bit about lightning - mostly because you can find supporting evidence for the effectivness of any coflicting theory about protection. I don't know what works.
A business colleague of mine lost his father to a strike when in his boat. (Dufour 27 with factory installed grounding) They think the strike hit him directly then went through the cockpit sole, set fire to the diesel then out via the shaft and through-hulls causing serious leaks. Horrible.
Near my club five years ago two boats were rafted together: one wooden (obsessivly grounded) the other glass (no grounding) masts same height - the strike hit the wooden grounded boat and sent side flashes THROUGH THE HULLS WHERE THEY TOUCHED. The grounded boat had major damage - the worst being her wooden rudder which literally fell into splinters the next day, while the glass ungrounded boat had gel coat damage. People were in both boats - no injury.
In our boat, when at anchor, there is a direct conductor to ground via our all chain rode (metal roller) but even then we had an experience two years ago where a storm was coming, and as we approached our boat I noticed my wife's long hair standing on end reaching toward the boat. Clearly a charge was building! Nothing happened although a yacht was struck several miles away that day.
I have clung to the hope that the bow strip might help.... I have also clung to the hope that we might never get hit!
----- Original Message -----
From: Wally Moran
To: public-list at alberg30.org
Sent: Friday, March 15, 2002 10:13 AM
Subject: Re: [Alberg30] Lightning protection
There are a lot of theories about lightning protection. One of those is that a thin, broad piece of metal on the hull is better than, for example, the strip on the A 30. Another says that creating a link from the stays to the water - for example, by using a battery cable with a piece of metal welded to the wet end - can help also. Still others suggest bonding all metal on the boat together and leading that to a proper ground on the keel. So there are lots of opinions, very little that is known for sure. Evidence seems to point to the thin broad metal. Also, a lightning bolt isn't just a small jolt. If the lead to ground isn't sturdy enough, the lightning can shoot out and connect to other pieces of metal onboard, or even pierce the hull in its search for ground, causing a multitude of small pinholes. You can imagine the fun that would be. There was a tale in Gam about one boater who suffered that fate.
You might check in Nigel Calder's books re lightning protection. Also, the ABYC standards are worth looking at. I'll look this weekend and see what other books address the issue and post that info later.
Have you considered prayer? As they say, there are no atheists at sea in a storm.
A posting to this mail group in 1999 suggested all Alberg 30's are lightning grounded by virtue of the stainless strip running from the stemhead down to about 3 feet below the waterline. It connects to the forestay and thereby providing a grounding from the masthead to the water.
Any comments as to whether this should be sufficient and what alternatives there might be.
George and Kathy White
Close Harmony # 637
email: salty at ns.sympatico.ca
Telephone: 902 893 1080
The gods do not deduct from man's allotted span the hours spent in sailing. Anon
www.georgianbaysailing.ca for interesting reading for sailors
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