Lightning scares the bejeebes out of me and I have spent many nights anchored out among other boats hoping that if lightning strikes it would find the
radio tower across the harbor or a taller mast ( without any ill will towards others) on a grounded boat around me more attractive than my own. When I first bought my boat which is a 1980 Dockrell 27 cutter and read the survey it revealed that my little ship is not grounded and this prompted me to do a little research on the matter. What I found out after exhausting the resources on the web is the following: In rough numbers a boat that is grounded is twice as likely to be hit by lightning than one that isn't. On the flip side, a boat that isn't grounded and is hit by lighning is twice as likely to catastrophic damage i.e. have a hole blown in the hull and sink and/or kill the crew. None of the sites I visited gave me any absolute statistics except for the ones selling products which in my sceptical way always assume are skewed. It seems also that grounding a boat doesn't provide absolute protection to the crew, especially on smaller boats where you cannot physically get away from the path the lightning wants to take to the ground, down the mast and out through the grounding cable and
line.
I don't really love any of these odds. What I have done to date is
not ground my boat and to further reduce the likelyhood of being struck I have installed a stainless brush at the mast top designed to "bleed off" negative ions thereby reducing the potential of the boat. Experts disagree as to the effectiveness of this system. As I write this though I am again wondering if I shouldn't ground my boat. The following link discusses the brush system in greater detail
http://www.oceanpix.co.uk/Seamanship...g-at-sea-2.htm