marine electrical system

A luxury motor yacht is basically a “powerboat,” albeit on a much grander scale. And, the power behind the power is your yacht’s electrical system. Without your yacht’s electrical system up and functioning, its motors would fail to start, its computers would not work, basically, she would be dead in the water.

The marine electrical system on a modern motor yacht can be very complex, involving multiple circuits, batteries, isolators, chargers, distributors and more!

Of course the exact power system and power requirements will vary, based on the size of the yacht, and components and amenities on board.

Marine Electrical Systems

While a modern marine electrical system is fairly self-contained, and for the most part should be trouble free, as you know, water and electronics do not mix very well. Corrosion is probably the greatest enemy of your yachts’ electrical systems. But before we get into problems and troubleshooting, it’s important that you know the basic components of your system, and what they do.

Here’s a brief overview of the main electrical components commonly found in modern motor yachts.

power hungry yacht

Your Yacht Has Many Power Requirements


Of course, batteries play a big role in your boat’s electrical power plant. There are usually two types of batteries found on power yachts: cranking batteries and storage batteries.

Cranking batteries are what provide the “juice” for your engines to turn over. Once the engines are up and running, the cranking batteries are not “in use” and are charged by the vessel’s alternators.

Marine Battery

Lithium Marine Battery

Storage batteries are what provide electrical power to your yacht’s lights, and run all of the electrical equipment and electronics on board. Storage batteries, particularly on large motor yachts that require a lot of power and amperage, are known as “deep-cycle” batteries. Deep cycle batteries can retain their charge for a long time, and can be depleted and recharged over and over again with little or no damage.


An isolator, or more specially a “battery isolator,” is what directs the flow of power from the ship’s alternators to a specific battery or batteries. Isolators are also there to make sure that batteries do not discharge from one to the other during operation.

Circuit Breakers

You are no doubt familiar with the circuit breakers in your home. The circuit breakers on your yacht serve the same purpose. They are there as automatic emergency power cut-offs in case of a power surge, which protects critical electrical system components from damage.


Again, like the fuses in your home or car, the fuses on your boat are your electrical system’s critical component’s first line of defense against spikes or irregular disruptions in power.

Fuse panel on yacht

Electrical Systems Planned Maintenance and Repairs

The marine environment can be especially harsh on the components of your boat’s electrical system. Most of the time that there is failure in any of the components of the system, it can be traced to corrosion or buildup of dirt on terminals or connections. The harsh sea environment can also lead to loose connections, frayed wires, damaged insulation, loose fuses, and fault switches.

Keeping the components of your motor yachts electrical system inspected, cleaned and fully operational, is all part of the planned maintenance you will find as part of our On Demand Yachting solution.


Operating a motor yacht can be costly. You can reduce your expenses, and avoid costly repairs by keeping her well maintained. On Demand yachting from FYM can help. If you would like to learn more, or if you have any questions or comments about this blog post, do not hesitate to contact our Yacht Management specialists, or call us at (954) 900-9968.