Originally Posted by Frogwatch
Having routinely worked with multi-million volt potentials, I disagree with some advice given here. One can minimize the probability of the strike going thru certain paths by offering a much better path and eliminating paths that you do not desire.
Most effective would be a very good lightning ground.
as they say in the electrical world, it is not the voltage that kills you, it is the current.
Similarly, lightning damage is a result of the current flowing, quickly. Anything that impedes current flow at inrush currents of millions of amp, is going to cause problems. Whether a mechanical splice, or welding clamp or simply some corrosion of a mast to clamp connection, that is a "high resistance" bump that the current will eliminate as a path to ground. It may blow it to pieces, or in many cases simply arc/jump to a better ground.
The ability to provide a "better path" is the challenge if it is possible at all on a boat, especially since the cable sizes and connectivity options preclude using adequate gear and there is no easy path to "ground" so water becomes the next best path to sink the current.
There is no such thing as a good lightning ground on land, let alone on the water.
All that being said, it is your boat and you are free to spend as much as you like on widgets and gadgets and cable and chains. Before spending or doing - You may want to ask to speak with an insurance loss analysis person at your insurance company and see what they will allow to be installed on your boat, and still provide coverage.
Check the web for radio tower hits to see what "good lightning grounds" look like after the strike. Some are 40' deep ground rods, with 250/500 CM copper connections to screens and such, and still are vaporized. Others are just fine and sustain multiple hits yearly, ala the Empire State Building transmitter tower. That is my background.