Losses and Lessons: Risk of a lightning strike isn’t limited to sailboats
Accidents happen. That’s why we work to ensure that our clients’ prized vessels are properly covered should disaster strike.
Lightning strikes are generally considered a concern only for sailboats, but the risk of lightning damage extends to anyone who leaves their boat in the water for any period of time.
While lightning typically strikes the highest point in a given area, if your boat is alone at the end of a dock, it may easily be the highest point relative to the water – especially if it is equipped with a VHF antenna or metal-framed Bimini top. Even mooring your boat near a sailboat or large cruiser could result in collateral damage from a lightning strike.
Wooden boats are no more likely than non-wooden boats to be struck by lightning; they are, however, more susceptible to damage from lightning because of their inherent construction material. Unlike the metal masts found on most modern sailboats, wood is not a good conductor of electricity; consequently, lightning does not have an easy path to follow as it works its way to the ground, thereby increasing the likelihood of damage as it seeks an exit.
It is pretty typical to see damage to a boat’s electronic equipment when lightning strikes. Unplugging equipment such as radios and GPS displays in advance of a storm can minimize damage in the event of a lightning strike; however, little can be done to fully protect your electronic devices from electrical damage.
In addition to electronics, damage to the hull is frequently another consequence of a lightning strike. Because electricity travels along the path of least resistance, the most likely escape routes for lightning are via metal through-hulls, the rudder and the propeller – potentially leading to engine damage as well. Either the through-hull fittings could be blown out of the boat, or lightning can indiscriminately blow a hole through the hull itself, with either scenario leading to a possible sinking. While electronics damage may be unavoidable, you can minimize the potential for sinking through a process referred to as bonding your boat: A one-square foot (larger if in fresh water) grounding plate can be affixed to the underside of the hull, with a large gauge wire leading to something that can act as a lightning rod (such as a metal radio antenna).
Don’t believe the misconception that only sailboats are at risk from lightning; it can be a threat to any boat that is not in covered storage. If your vessel endures a lightning strike, it’s a pretty good bet that there will be some damage. However, there are steps you can and should take to help protect your boat and ensure that the potential for catastrophe is diminished. We recommend that you seek out a qualified marine electrician to ensure your boat is properly grounded, in addition to scheduling annual inspections of your bonding system.