Octopus Electrical Service

How to protect your yacht against lightning?

As per the insurance claims department (of BoatUS Marine Insurance), the cases of boat lightning have increased from 1 per 1000 to 3.3 per 1000 in the lightning-prone areas of Florida. According to Pantaenius, the relative share of lightning damage in the total losses each year is 10% and much more in the cruising regions such as the Mediterranean, parts of Pacific, and Caribbean regions. According to Pantaenius’s Jonas Ball, the total number of lightning damages has tripled in 15 years. Note that steel and alloy boats are far less likley to be affected as they are self grounding


According to most UK and US-based insurers, multihulls are two or three times more prone to lightning than monohulls. The reason being more exposed surface area and lack of keel and adequate grounding. The cost of strikes has also increased as yachts carry more electronic devices and systems.


How To Avoid Lightning Strikes?


The only defensive measure to prevent your yacht from lightning is to avoid the lightning-prone areas. Based on the data provided by NASA, the lightning hotspots are Florida, Cuba, and Colombia in the Caribbean, Malaysia, Singapore, and West Africa. Also, most of the famous cruising grounds are located in tropical waters only. So monitoring weather and flexibility to change plans is an essential part of the channel.


Protection against lightning strikes


There is some Yachts lightning protection experience far-reaching damages.  So it’s practical to implement a protection system in the boat to prevent lightning damages. 

First, analyze the boat and the relative positions of the top metallic fittings to disclose the places to avoid and safer places to hide. Areas below the steering pedestal and near the engine are the highest damage-prone areas.


One of the most common practices to limit lightning damage is to direct the current outside the boat using heavy electrical cables attached to the stainless steel rigging and the other end of the cable immersed in the ocean, providing a conductive path from the masthead to the ground. Also, ensure adequate copper to be in contact with the seawater to discharge the lightning current.

Other temporary practices to avoid lightning damage include disconnecting radar and radio aerial cables, keeping portable electronic devices in the microwave, turning off all the batteries, and unplugging the shore power cord.


Permanent lightning strike protection

Well, here we have listed some of the permanent lightning protection. Without further ado, let’s jump into the list!



Lightning rods installed at the top of the mast and connected to an external grounding plate on the hull allow the current corridor to enter the water. Heavy electrical cables can also be used as a down conductor. A single plate near the base of the mast is sufficient for monohulls, while Catamarans usually require two grounding plates. A schooner, ketch, or yawl requires a straight down passageway for each mast and an extended strip under the hull between the masts.



The bonding cables help to prevent internal side strikes. With bonding cables, an internal bonding circuit attaches the metal objects on the boat to the grounding plate. It is very crucial to ensure the correct design of the bonding system. The five possible grounding systems on a yacht, including lightning protection, bonding for corrosion, SSB radio ground plate, AC safety ground, and DC negative, should be joined at one point and finally connected to the external grounding plate.


Surge protection and EMP protection

During a thunderstorm, the yacht’s lightning anchored close to shore or shore power lines are more vulnerable to voltage pitch. The lightning current traveling down the electricity cable can enter through the shore power line or can pass through the water and flashover to a yacht at anchor. So Surge-protective devices (SPD) are used to prevent the vessel from lightning.


These devices are self-sacrificial devices that ‘shunt’ the voltage directly to the ground. These devices reduce the voltage spikes. For example, a 20,000V surge can be weakened to 6,000V. Although the extra current is still enough to damage the sensitive electronics on the vessel. Hence fitting a ‘cascaded’ surge guard with several Surge Protective Devices in line is an excellent design.


High-tech solutions

Few high-tech solutions can also be equipped on vessels to prevent them from lightning. For example, Lightning dissipaters prevent a lightning strike. It bleeds off an electrical charge on the rigging at the same rate as it builds up and hence reduces the lightning strike. Bottle brushes acting as lightning dissipaters are occasionally seen on cruising boats. Modern dissipators however ball tip at the end of a tapered section of an aluminum or copper rod.


One more high-tech solution is Sertec’s CMCE system. The CMCE system attracts and grounds the excess negative charges from the atmosphere, hence preventing a lightning strike. However, the system works within the cover radius of the device. It claims to diminish the likelihood of a lightning strike by 99%. The CMCE system is widely installed at airports, hospitals, and stadiums. Now the same has been tailored for undersized marine uses also.



Well, the best way to evade damage from lightning is to evade the lightning on the whole. So what to do about protecting your yacht from lightning? The most common mistake most of the sailors do is to do nothing.

The straightforward purpose is to channel the lightning electricity bolt down the mast, to the water, as quickly and simply as possible.


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