Anonymous wrote:
A little bit of reading about what the professionals do in the field of marine lightning protection tells me that it's a very complex subject, and unskilled amateurs are just as likely to make things worse as make them better.
http://www.marinelightning.com/index.html
This link is the one that will possibly be of most interest to us:
http://www.marinelightning.com/science.htm#Cruising_sailboats
I'd about reached the same conclusion after reading the PDF I posted David, fascinating read that, it explains in layman's terms exactly what happens when lightning strikes a mast. Now that I'm a bit better informed I'll probably do as the experts recommend and a bit more besides.
Thanks for the links David, very helpful, and now I'm even more worried, according to the stats on strikes by boat type a catamaran is about 12 times more likely to be struck by lightning than a sail only monohull and sustain about twice as much damage!
and I'm working on a proa which is essentially an asymmetrical catamaran, I guess sometimes ignorance really is bliss.
On the upside, there will be very little metal or electrical on my boat, just the woodstove and stovepipe, and handheld devices that'll be stored in a waterproof plastic case when not in use, and either a windmill or solar panel and a charging station for cordless tool batteries which I'll use to power LED lighting.
Because it's a telescoping mast and they tend to get a lot of rain running down the top section into the bottom section that needs somewhere to go, I already have a drain hole through the bottom of the boat drawn for the mast step so it'll be easy to put a cable out the bottom.
And on the Proa I'm designing the mast step will be outside of the water line in the flare of the hull so it'll be even easier to ground.
I must have been writing my last post when you posted Arne, I like your idea, so much that I'm giving serious consideration to standing rigging, something that I really wanted to avoid, a couple stays with copper cable clamped to them leading to the ends of the ama would protect the cockpit area between the hulls and lead the charge away from the boat. A stay to the bow with the wood stove would protect that a bit as well.
here's a link to a Sidearc System which takes your idea a couple steps further, lots of great info there both on what happens during direct strikes and near misses.
One question though, since you've probably forgotten more about electricity than I'll ever know, why an insulated wire? As I understand it, (Not very well) insulating a wire raises it's resistance, considering that the average lightning bolt is around a billion volts and from 10,000-200,000 ampres, wouldn't that just vaporize the insulation?
Well, time to stop planning and start doing :)
Speaking of which, just started on an aerojunk rig.
Bill F