It wasn’t long ago that even ambitious cruising yachts had only the bare minimum in electrical systems. Navigation lights, a VHF radio, perhaps an electric windlass and a single GPS plotter were about as sophisticated as things got.

Power demands were modest, and we managed with a decent-sized battery bank, topped up now and then by the engine alternator.

Modern cruisers are a different story.

Today’s yachts are expected to run fridges, freezers, laptops, and autopilots as standard. These place a heavy drain on the house battery bank.

Add in watermakers, air conditioning, or even induction hobs, and you’re into the realm of AC power demands as well.

This is where a generator can become essential. Not only can it keep your batteries charged without prolonged engine use, it also powers those high-demand systems that require 230V or 110V AC.

Choosing a generator, however, is not something many yacht owners will have done before.

At Rubicon 3, our vessels operate year-round, from the icy seas of Greenland and Svalbard to the Caribbean’s sweltering humidity. In between are many ocean crossings and many nights at anchor, with our crews relying on their generator for power, heat, refrigeration, desalination, and more.

It means our yachts need a generator that can handle variable loads smoothly, work hard every day in a commercial environment, and above all, remain reliable.

Unlike items such as foul-weather gear, where you can try something on and trust a few reviews, selecting a generator is more opaque.

Manufacturers such as Fischer Panda, Northern Lights, Onan and WhisperPower all have confident sales teams and polished brochures, but once you’ve filtered out the marketing spin, how do you make the right choice?

Fisher Panda 8000i installation in one of Rubicon 3’s adventure yachts. Photo: Rubicon3

Know your load

The first step is calculating your expected electrical load, including peak expected draw and a lower ‘duty cycle’.

This will narrow the field.

You’ll find that generators are usually rated in kVA – their total output, including wasted or ‘non-working’ power due to inefficiencies in the electrical system. They should also give an output in Watts (far more helpful to know), which will usually be around 80% of the kVA.

So 8kVA gives around 6.5kW, enough to run the kettle, toaster, battery charger and watermaker – though never more than two at once.

Check the physical size

Once you’ve got a shortlist of models that can meet your power requirements, the next crucial step is ensuring it will physically fit, not just into your engine room, but onto your bearers or generator platform – and, if not, what modifications you need to make.

Some models are compact and modular, while others are bulky and require greater installation space. It’s not the most exciting aspect of choosing a model, but it is quite key!

Rubicon 3 chose Fischer Panda generators for its fleet of yachts because they best suited the firm’s operating model

Fixed vs Variable Speed: The Trade-Off

You’ll also see that some models are fixed speed and others variable.

Variable speed generators adapt engine speed to the load demand, while fixed speed sets run at one speed, whatever the load.

Variable speed generators are, therefore, ideal for vessels with constantly fluctuating loads. They’re usually quieter, more fuel-efficient under light loads, and generally more compact. But they’re also more complex and there’s more to go wrong.

Fixed speed generators, on the other hand, are usually simpler but slightly heavier, noisier, and less efficient when running below capacity.

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Think Beyond the Spec Sheet

Equally important to your choice should be after-sales support.

The most sophisticated generator won’t help you if there are no service technicians or parts suppliers in your part of the world.

Look at the brand’s service network in the regions you plan to sail.

Again, quick access to support and spares is not glamorous to prepare for, but you’ll be very pleased that it’s there when you need it.

Fischer Panda generator

The Reality of Ownership

Having worked as an engineer on superyachts and managed multiple different generator brands in the Rubicon 3 fleet, i can honestly say this: if a generator is properly installed, operated within its limits, and serviced correctly, most of the major brands are very good.

I have not found that any one brand stands head and shoulders above the rest in terms of reliability.

Final Thoughts

Choosing a generator for most cruising yachts is part of careful research of the items listed above and the happenstance of which generator is available near you, at the time you need it, and the price you can negotiate.

Take time to specify it correctly, plan for access and support, and match the system to your operational needs.

Do that, and whichever brand you choose, you’re likely to have a generator that repays your trust when you’re hundreds of miles offshore or in the wilds – and that’s what really matters.

If you enjoyed this….

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