I have a 28' Corsair folding trimaran with all plastic/FRP hull in contact with the seawater (i.e. the mast is not electrically connected to the water). Historically these boats have not been struck by lightning while on the trailer with the mast raised but... on the water they have been struck. The strike generally carries down the SS shrouds to SS chainplates that are located about 12" inches from the waterline. From there, the strike is quite destructive, generally punching 1/4" holes thru the hull delaminating FRP as it goes. I'm trying to bond the mast to the water using NFPA and ABYC standards in the system design. My limitation is that I do not want to bolt a 100 sq in copper plate to the hull for drag purposes (race boat). So, I'm thinking of using a temparary system of heavy guage copper plumbers tape (7' long, > 100 sq in exposed surface area) with lots of edges towed thru the water by a #8 Cu THHN wire bonded to the mast with a lug.
My questions is two fold: one general comments on whether the temporary system would work and improve the situation, and two... how good of an electrical connection would I need to make to the mast? I would like to install a bolt on lug to the mast and am questioning which materials to use? Al, SS, Cu Lug? Al, SS, Cu Bolt? The mast is 3/16 extruded aluminum section. Also trying to minimize any galvanic corrosions between the mast and the lug. My best guess now is Al mast -> 3/8" threaded hole ->Al bolt -> Al lug to copper wire.
I'd appreciate any tips/advice.
John
My questions is two fold: one general comments on whether the temporary system would work and improve the situation, and two... how good of an electrical connection would I need to make to the mast? I would like to install a bolt on lug to the mast and am questioning which materials to use? Al, SS, Cu Lug? Al, SS, Cu Bolt? The mast is 3/16 extruded aluminum section. Also trying to minimize any galvanic corrosions between the mast and the lug. My best guess now is Al mast -> 3/8" threaded hole ->Al bolt -> Al lug to copper wire.
I'd appreciate any tips/advice.
John