The Chances of Sailboats Being Hit by a Lightning Strike
Some will argue that the size and type of your boat do not matter when it comes to lightning strikes. This is not true since some boats have been reported to be more susceptible to lightning strikes than others.
Lighting strikes are not your fault but there are some things you can do to help lower the chances of your sailboat being struck by lightning. While there is no guarantee in a lightning protection plan, having all materials and actions ready beforehand could save you money and someone’s life.
Multihull Sailboats
Multihull sailboats like catamarans or trimarans have a 6.9% chance of lightning strikes a year out of 1,000. Multihulls lack keels and with more exposed surface area face a greater risk of lightning strikes. Modern multihulls come with complex electronic systems that usually lead to costly damages from a lightning strike.
Monohull Sailboats
Monohull sailboats have a slightly lower occurrence of lightning strikes than multihull sailboats at 3.8% out of 1,000 per year. Just because they are less likely to be hit with lightning than multihulls does not mean you are in the clear.
Other Types of Boats
Other boats such as trawlers, bass boats, and even pontoon boats are at lower risk individually. These boats have less surface area and some are not even designed to be offshore where storms are intense. When combining those and all other boats besides sailboats, the risk of being struck by lightning is 0.9 out of 1,000.
Length of Sailboat
Your mast is an extension of your boat so you should sit and wait for the weather to pass before heading out to sea. According to Martin Uman, who leads the Lightning Research Group at the University of Florida, sailboats with 20 to 30 feet taller masts are almost three times more likely to be struck by lightning. This is due to the nature of electrical charge transfer between clouds and the ground despite lightning bolts being typically five miles long and one inch wide.
Sailing in the Rain
Rain clouds hold water and thunderstorm clouds carry electric charges. Interestingly enough, sailing in the rain is fine, but the accumulation of storm clouds is dangerous. Your focus should be on Nimbostratus and Cumulonimbus.
Nimbostratus clouds are flat, large, and closer to the ground. They can produce precipitation and span vast areas at a time. Safe boating in these conditions requires proper measures such as adequate rain protection, safety gear, GPS, and lighting for navigation and anchoring.
Why Are Sailboats a Target for Lightning Strikes?
Lightning strikes can hit boats during a lightning storm since some have metal masts and antennas. You are more susceptible to a lightning strike due to conductive material and turning your boat into a giant lightning rod.
This is especially true for sailboats with high aluminum masts since lightning can hit the mast before anywhere else on the boat. Fiberglass boats sitting low on the water are less likely to be struck by lightning.
How to Prepare for a Potential Lightning Strike
Boaters must be familiar with essential safety guidelines for thunderstorms. A practical approach to lightning protection is providing a safe discharge path for lightning. No technology currently exists to prevent lightning strikes so preparing for the worst is all you can do.
Update Insurance or Check the Policy
Ensure your sailboat has adequate insurance. If you do not have any or want to change you could always check out what BoatUS Marine insurance can do for you.
Seek Weather Updates
Equip modern weather detection gear and check the forecast before sailing. If thunderstorms are predicted you should stay in the harbor until the weather clears.
You can always tune into the VHF radio weather channel that is typically found on channels one through nine depending on your area. This gives you timely storm updates and critical information if you are out while a storm arrives.
If Stuck in the Middle of a Storm
Storms that will likely produce lightning strikes can pop up at a moment's notice at sea. If you are unable to outrun the storm, here are a few tips to consider:
- Wait it out and keep your shoes on while avoiding metal objects.
- Hold onto non-conductive items like fiberglass but beware that water can conduct electricity.
- Keep a hand in your pocket for safety and ensure no metal is inside.
- Use a vital piece of wood or rubber to control the steering wheel and set the throttles at idle or low throttle.
- Lower the antenna, outriggers, and any fishing rods.
- Stay close to the middle of the boat and remove any metal jewelry.
- If lightning strikes the boat you should immediately ask if everyone is okay and look for a hole that the lightning went through to ensure you are not taking on water.
Keeping Electronics Safe
It would be best to use transient voltage surge suppressors (TVSS) to safeguard crucial and lightning-sensitive equipment such as ECU/ECM, chart plotters, and instruments. These semiconductor devices suppress lightning-induced voltage spikes and are widely used in aviation, wind power, and telecommunications.
TVSSs function like voltage-sensitive fuses and redirect excess voltage as heat. Using TVSSs is a wise investment in preventing lightning damage to equipment even though this heat may damage them.
Ground Your Sailboat
For a grounding system, you should install lightning rods or terminals on top of the mast and connect them to the grounding plate to protect it from lightning. Use cable as a down conductor for wood or carbon masts and retrofit the grounding plate during haul out.
Monohulls require one plate, while ketches, yawls, and schooners need a path for each mast and a strip under the hull. Catamarans need two plates but a more extended plate outline is better for current dissipation.
Internal Bonding Circuit
A bonding system is a circuit inside a boat that links main metal objects to the grounding plate with cables. This reduces the risk of internal side strikes caused by current jumping between objects towards the ground.
