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Morgan3820 · 25-05-2011, 18:24

I had made a ground plate out of 4" x 18" x 0.5" copper plate. In the plate I had parallel groves cut lengthwise. The grooves are 0.25" deep and wide, spaced 0.25" apart. This gives me around 1 sqft and almost 12" of 'edge'. It is bolted to the hull with 3 - 1/2" bronze bolts. A 4/0 cable attaches it to the mast. Pretty cool huh?

I also have the bottle brush on the mast. A surveyor once told me that he surveyed 14 boats that year that had been hit by lightning and none of the boats hit had the bottle brush. Doesn't prove anything but for $80 bucks it can't hurt.

niel12 · 25-05-2011, 21:37

Now aint that somethin! Excellent posts that proves the importance of planning, nothing can beat that! Improve the odd's as i am told by the experts that if one could capture a lightning bolt and relay the electric charge New York could have free lights for about 5 days! That as a magnitude of power simply just wet my pants, period!

Having a ground plate connected to the mast and wiring to connect to stays and shrouds is no garuntee for a miss, it kind of even odds about .005%. As Mark said doing nothing does not make any sense so do what you have to do or can afford to do even the odd's out somewhat.

niel12 · 25-05-2011, 23:23

Something that caught my eye in another thread on lightning was the reality of side flashes in a strike. Question i do not know is when a lightning strike dissapate through the groundplate into the sea water what are the odds that strike flash back track and burn a hole beneath the groundplate? Would inserting a rubber behind the ground plate, say 5 mm thick not combat such a possibility?

arjand · 01-07-2011, 10:28

I hope this does not qualify as reviving dead threads... One follow-up; is a copper plate that much better than the wire to the keelbolt?

niel12 · 01-07-2011, 11:02

Ahoy there!

May i suggest that you read through the posts. There is some real good points raised for and against the principles. What confuses me is what older sailors did was to throw a cable connected to the mast over the side into the water. And that was that. In my mind ther's a whole lot of good sense in that, especialy if one think of a flash back from strike diversion path to a ground plate or keel bolt. Frankly a flash back can punture a hull and suddenly the simplicity of throwing the cable over board seems by far the safest and simplest, most effective and cheapest method.

psneeld · 01-07-2011, 11:08

Read all you want...the best way to protect your boat is to keep it moving...the best way to protect onboard electronics is to disconnect them totally...power cords and antennas...other systems are in jeapordy from EMP (electromagnetic pulse) from a hit or even nearby strike). If high voltage power transmission cables can't survive a direct strike...what can u add to a boat that can?

Anyone that tells you something definite is making a big guess...the more you read... the less you believe is possible in preventing damage....you are at mother nature's mercy when it comes to lightening...things help...but can't prevent or lessen a direct strike.

niel12 · 01-07-2011, 11:31

Agreed that is the only good preventitive measure for electrics and cables in a electric storm. Beyond that, well you are for sure at mother nature's mercy. But i still like the old salty guys idea of a cable over board!

psneeld · 01-07-2011, 13:42

Quote:

Originally Posted by niel12

Agreed that is the only good preventitive measure for electrics and cables in a electric storm. Beyond that, well you are for sure at mother nature's mercy. But i still like the old salty guys idea of a cable over board!

Good idea at anchor...especially the bottle brush idea too...preventing the strike and handling spikes with a cable are OK...nothing will protect from a main direct hit though...underway....cross your fingers but I think underway strikes are pretty rare as you aren't sitting on top of a "potential difference" for very long...

zeehag · 01-07-2011, 13:49

watched bottle brush attract lightning--i wont do anyhting except have a set of jumper cables handy or qattached--i use feline, crocs, and rubber suit with gloves. my own boat is wood masts. and not tallest-- taller than me are sloops and cutters and schooners.LOL
HOWEVER lightning is random and protection has not been proven to help prevent strikes.

markpierce · 01-07-2011, 21:38

My lightning rod is the pointed rod rising from behind the anchor light.

niel12 · 01-07-2011, 21:49

Hey Mark, that's evening the odds somewhat, say about 0,01 percent?

I stand by you "doing nothing does not make any sense," doing something even if it's just bare minimum, could increase your survival rate no matter how much. Who can determine how much is enough?