There is no such thing as a lightning-proof boat, only a boat that is lightning-protected. A properly grounded boat is made to reflect the energy and electrical charge of a lightning strike away from the people and electronics on the boat, and onto the water’s surface. Many people are under the misconception that the energy of the lightning strike is supposed to be spread out over the frame of the boat, but the energy must be diverted to the water’s surface, an extremely conducive matter.
If the electricity from a lightning strike were allowed to spread throughout the hull of your boat, it would cause major arcing of electricity from wires to wires, even those of higher gauge with heavy insulation. Electronic components, like solenoids, resistors, capacitors and other items will easily melt under the amperage that comes with a high-voltage lightning strike. The amazing energy that is zapped through the boat’s electronics, and it’s passengers, is spread out to the water instead by installing proper lightning dispersal equipment to your boat.
In order to make your boat more lightning-friendly, you should first determine the most likely points that the lightning is bound to hit on your boat. Any communications towers or radar posts are likely lightning targets, as is a down-rigger. Basically, anything made of a metal that sticks out from your boat. You should run a heavy gauge wire from any probable lightning attractors to lightning grounding strips that are touching the water. Connecting the grounding strips to a metal plate, about an inch thick and a square foot in size, submerged about a foot down in the water, makes for a great grounding method, and is one of the best ways to come close to lightning-proofing a boat.
In trying to make your boat as safe from lightning strikes as possible, you should realize that you, and your passengers make some of the best electrical conductors, since we are made predominantly of water. You can drill some holes through the hull, near the bottom of the side of the boat, and insert electrodes through, half-way, so that half of them are in the boat, and half in the water. When a storm strikes while you are still out on the water, everybody in the boat rests their feet on these reverse-lightning rods, which disperse the electrical current from the dazzling bolt of power, from the hull outwards into the water and away from the electrical components, and, of course, the people on the boat.
If, for whatever reason, you find yourself out in the water during an electrical storm, and did not see it approaching dark clouds, increased barometric pressure and higher winds (maybe the lake was surrounded by large hills or mountains), you should immediately head for shore, and get off of the boat as soon as possible. Try not to jump into the water to get to shore, unless you are a mere few feet from dry land.
Boat safely, boat informed.