Taking the load off

It used to be a tough choice for superyachts: either accept very high gearing on the helm or lose the direct feedback from the rudder. Now there’s no need to compromise

Aquarius II, a 65m ketch launched by Royal Huisman in October 2024 and now in the process of sea trials, will undergo extensive sailing during 2025 preparing for the superyacht regattas in 2026. A development of the owner’s previous 56m ketch, Aquarius II will be the first yacht to feature Edson’s Electric Power Assist Steering (EPAS). EPAS gives the helm five levels of assistance without losing any of the feel at the wheel. Edson’s marine products manager, Dave Kirkpatrick, outlines the problem EPAS solves.

‘Because of a superyacht’s power you can either have a lot of wheel turns to control the steering, 8-10 turns lock-to-lock, or you can use a hydraulic system in which case you get no helm feel,’ Kirkpatrick explains. ‘The Edson technical team set out to significantly reduce the number of turns of the wheel to move the rudder from lock to lock, without making it harder to hold the wheel, while still providing real rudder feedback to the helm. Sailing the 56m Aquarius on a powered-up spinnaker reach required Mike Sanderson, the yacht’s racing skipper, to work pretty hard turning the wheels almost a full rotation in both directions to keep the yacht on track. The new Edson EPAS system will reduce the number of turns by 60 per cent and allow for significantly less load felt at the rim of the wheel.’

The Edson EPAS system will allow Sanderson to sail the 65m Aquarius II on a finer line with less work, but more importantly, the owner or his grandchild will be able to enjoy the same ease of steering while still feeling the rudder feedback.

Edson was still at the conceptual stage of development when Godfrey Cray, project manager for the new boat, committed to EPAS. Edson’s technology partner at the time had the company using a system adapted from the automobile market. Chip Johns, who acquired Edson in 2021, dug deep into his engineering background and put together a team of engineers to bring the EPAS concept to reality using robust industrial components and state-of-the-art haptic control software to deliver the finished product. ‘Our first test of the new system was one of these “aha” moments that convinced us we had a game-changing technology’, Kirkpatrick says. ‘Once we had the proof of concept tested at the loads we expected, we refined the software and hardware for the final system which was installed by Royal Huisman in the winter of 2024.’

Which yachts can benefit from EPAS? Any yacht whose owner or skipper wants to reduce the number of steering turns and rim load while maintaining the helm feel that performance sailing depends on.

One of the features designed into the system is the five assistance levels. What was the thinking behind that? ‘It allows the user to match the assistance to the load,’ Kirkpatrick says. Sailing upwind on a well-balanced, well-trimmed boat, different drivers might move between level one and three. However the owner’s granddaughter might want to take the helm, in which case she could dial it up to four or five and be in complete control. Once you turn the corner and head off on a powered-up reach, dialing the assistance up will be enjoyed by all the drivers, and by reducing the number of turns of the wheel Sanderson thinks he will be able to steer the yacht through a narrower range of headings.

‘We’ll be retrofitting EPAS on a 60m-plus yacht over the winter of 2025,’ Kirkpatrick says. ‘The two elements that need space are the torque sensor and the power unit. Each setup is a little different but our design allows for a fair amount of freedom in the location of these components. Once the system is installed, the maintenance is the same as a regular system.

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