Join Date: Mar 2006
Location: New England
Thanked 17 Times in 13 Posts
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The people in your marina are deluding themselves into thinking they're protected... they're not. Shrouds and stays, made of 316 stainless steel, are very poor conductors of electricity, and the connection of the wire to the shroud is questionable at best, given the amperages we're talking about here. The wire's bare end trailing in the water also doesn't provide enough edge for it to act as a good boat-to-water grounding surface.
Ideally, you should have a heavy (4 AWG or heavier) wire running down from your mast, which acts as the primary lightning path on most boats since aluminum masts are fairly decent conductors of electricity, and down to a bolt or stud that attaches to a metal plate faired into the hull. The plate should have four linear feet of edge at a minimun—a 1' x 1' plate would do, but a 2" x 2" plate would be better—to dissapate the charge into the water.
The conductor connecting the mast and the stud should have as straight a path as is possible, since lightning doesn't like to turn corners. If you also bond the shrouds, stays, chainplates and stanchions to the same plate, it will create a "faraday" cage for the boat made of the standing rigging, and that should protect the passengers on-board from a direct strike.
YMMV... on some boats this works well, on others, not so good... If you have an external bolt on keel, the keel can often be used for the lightning ground surface—but only if it is external. Doing so with an encapsulated keel is a really bad idea.
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You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.
—Cpt. Mal Reynolds, Serenity (edited)
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