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One of the least understood natural phenomenon is lightning, and a great deal of confusion surrounds what is known as lightning protection. Many boaters believe the term "lightning protection" means "strike prevention" and that they won’t be struck if a system is installed. But lightning protection systems are not capable of preventing lightning strikes to boats. They are designed to direct the electrical discharge if your boat is struck by lightning in a way that minimizes damage to the boat and injury to the crew.
There are two schools of thought among lightning experts on protection systems for boats. One school holds that it is not necessary to protect a boat at all. The other school sees value in a lightning protection system. But what constitutes proper protection is still being debated. Perhaps with a better understanding of lightning and lightning protection systems, you can make a more knowledgeable choice about whether or not to have a lightning protection system installed on your boat.
During the thunderstorm season hundreds of boats are struck by lightning, and while few of these strikes result in personal injury, damage to spars, rigging, engines, electronics and electrical systems, as well as sinkings, can be counted in dollar value only by insurance companies.
Lightning is the result of the difference, or potential, between positive and negative electrical charges. These differences in electrical charges can be measured in hundreds of thousands of volts. The positive charges are usually higher in a cloud formation while the negative charges are lower, resulting in electrical current movements within a cloud, between clouds, or from cloud to ground. There is also evidence that the potential can travel in the opposite direction, that is, from ground to cloud, meaning that the positive charges are accumulating on objects on the ground below the cloud.
Negative charges always seek their positive counterparts, but because air is a poor conductor of electricity, this buildup of electrical potential searches for a conductive path between the positive and negative charges until the energy is released in a sudden flow—lightning. The basic precept to remember about lightning is that it searches for a conductive path to ground. Only when the insulation of the air can be overcome by huge amounts of energy is the electrical potential, or difference between positive and negative charges, released between the cloud and the ground as a lightning bolt. In the case of a boat, water is the "ground" and the lightning will use the boat as its path to earth, just as it will use the human body, which is mostly water and a much better electrical conductor than air.
When you install a lightning protection system on your boat, you’re providing a direct path to ground, which is an invitation for a lightning strike to come aboard. This is the great irony of lightning protection systems—unprotected boats may actually be struck less often. But when they are struck, they usually suffer more damage. A boat with a good lightning protection system, on the other hand, may actually have a greater likelihood of being struck, but the strike is dissipated and directed away, usually with minimal resulting damage.
Because metal is a well-known conductor of electricity, aluminum and steel boats are likely to suffer less damage than wooden and fiberglass vessels, which are fairly good insulators. This is not to say metal-hulled boats aren't hit by lightning, only that they can dissipate the strike more quickly because of their conductivity to ground. If your boat has a wood or fiberglass hull |
