Reason for the square edges: the 'point' where sharp edges meet will allow lightning a quick, clean exit from whatever it is running over. Lightning travels along the surface of things, and doesn't like to turn - so it's like Wile E. Coyote on a cliffs edge when it comes to a square turn, and off into 'ground' it'll go.

At least, that's what I've read/"they" think...

One company markets a ridiculously expensive copper pipe thingy that has points and sharp edges all over/inside of it. They claim that it has, for the diameter of a relatively small pipe, some huge amount of surface area thus exposed to ground. More hydrodynamic that a plate. Seems like you could get the same result with one of those "static dissipating" brushes, stuck in the water instead of at the top of the mast.

I've thought to devise a folding or telescoping arm(s) that just flips down into the water behind the boat from off the backstay(s), try to keep edges and surface disruptions on it to a minimum, see if I can't make it a nice "off ramp". The other thing is the external chainplates; my uppers are going to terminate close enough to the water that if I am heeled, it'll be a short jump there, too.

Of course, keeping a battery jumper cable coiled in a accessible box is another easy layer of (hopeful, isn't it all?) protection.

I'm with you, Ebb - our boats are too small inside, to be sharing it with gazilabazillions of volts. And I don't want to live with large diameter cable/wire artfully looped all throughout the cabin. Because it would have to be intrusive, to make that kind of ground system effective, IMHO.

Wandering farther afield: The idea of the new synthetic rigging tickles my noggin; being able to keep a supply of small diameter line aboard instead of a big coil of SS wire for rigging repairs/replacement makes more storage sense. But I wonder at the ability of the miracle fiber to handle the temps of a lightning strike. And having the mast held up solely by 'rope' means any lightning which comes has only one conductive path down - and that's straight to the cabintop.

Might be a good thing for emergencies, though...

Contemplating using something like this FRP rod for the 'core' of my 'ribs':

http://www.trippplastics.com/product...s.asp?catID=22

It looks like the Pearson factory used a side grinder disk to trim the edges of the cabintop liner, because I can see where the under skin was penetrated by just such a device. I'm going to need to remove 3-4" of the liner, in order to bond directly to the underside of the deck. Trying to think of how best to do that, what tool to use. Dremel comes to mind, but I wish I could find something more along the lines of a "nibbler" like sheet metal workers use...