Thanks Oliver & Bill,
Fantastic response but I think my question was a little missleading. I am not so concerned with lightning. (well I am concerned but am off the belief that if it is going to get you a little wire is not going to help much)
What I am more worried about is corrosion. My understanding of the bonding system is not just to be able to determine if there is a leak, but also to protect the important componets (mast, thru hull fittings etc) from corrosion by bonding them to the zinc annodes. I might be wrong but is the bonding system not connected to the rudder annodes?
I am sure that the thru hulls should be bonded (it even looks like perhaps at one point mine may have been) I would also think that bonding the masts, handrails, headsail track etc would help prevent corrosion. I have recently removed and refitted all the mast fittings and reapplied tef-gel. Even so there was some signs of corrosion starting on the mast. Also there is some corrosion on the headsail track where a stainless bolt passes though it.
This may well be just a case of deteriation on a 30yr old boat, but wouldn't bonding these items help?
Mahiti Maramu #147