When anchored during thunderstorms, I have a 2'X 2' piece of copper
sheet attached to OO guage stranded tinned ground braid that I attach
to my shrouds. However, this cannot be used underway because it would
trail in the water. I do not want to attach the sheet directly to the
hull because of my fears of 10E12 watts being disspiated against my
hull in 50 microseconds.
However, why not wrap the sheet around the rudder and use the ground
braid to attach it to the backstay? This would give plenty of surface
area and keep it away from the hull. A strike might disable my rudder
but I have a backup rudder I could use.