Revamped Juliet at the vanguard of modern refit

Future-proofing a yacht built in 1993

BY MAX STOTT

Sailing yacht Juliet defines the emerging era of ‘the new classic’ type of yachts. Here, we speak with Stefan Coronel, refit manager at Huisfit, about how they were able to implement hybrid technology on to an ageing vessel to ensure it could sail for years to come.

Photo: Captain Jonathan Allan

Last year, Royal Huisman’s Huisfit relaunched the 29-year-old 44-metre sailing yacht Juliet with some brand-spanking new technology and engineering. It was a refit case study that made headlines for all the right reasons and proved to the rest of the market that it’s possible to redefine the classic fleet.

Juliet now features the latest hybrid technology benefits, including silent operation, peak-shaving, shaft-generated power under sail and reduced fuel consumption, combined with enhanced operational flexibility and redundancy.

The centrepiece of Juliet’s hybrid conversion is a new gearbox, aligned with a new electric motor/generator. This facilitates indirect electric propulsion, either generated by the main engine or drawn from the new battery bank or generator. Conventional shaft drive directly from the engine also remains an option. The system enables the main engine to meet the yacht’s hotel-load requirements by means of the electric motor/generator, while the power management set-up provides additional silent options via the battery bank.

With the main engine becoming the primary source of power generation, the system is configured to deliver peak shaving from the battery bank, such as during sail hoisting and manoeuvring. The thrusters are electrically, rather than hydraulically, propelled. The same battery bank will enable silent-ship operation, including air-conditioning and hotel-load consumers.

Under sail, electrical power will be generated by the propeller’s rotation. Rapid recharging of the battery bank is provided by the electric motor/generator driven by the main engine or generator. At anchor, battery power replaces the gensets as the main power supply, eliminating the noise and atmospheric pollution.

These are, of course, some pretty major engineering upgrades for a yacht that was built before the turn of the millennium. Refit manager Stefan Coronel says he anticipated some initial challenges even before the yacht entered the yard.

“Juliet was delivered by Royal Huisman in 1993. The number of systems in a contemporary engine room is much larger and the technical requirements are of a very different, much higher level,” says Coronel. “That made it rather challenging to start designing a modern hybrid-based engine room within the existing space of this yacht, which was built almost 30 years ago.

“With the recent Huisfit project of Foftein [Royal Huisman, 1999], the team had gained experience with the conversion from conventional drive to hybrid drive. So the refit of Juliet was based on a tested concept, and lessons learned [such as improved interface and controls] could be applied as improvements in the refit of Juliet. Also, the rapid development of this technology led to further improvements.”

All the upgrades mentioned above mean there’s much less dependency on the main generators in their traditional role. They will offer a high level of redundancy, both for the propulsion via the diesel-electric system and as an alternative source of electrical power generation. In the latter role, the main engine’s generator would typically be the first choice for recharging the batteries after hours of zero-emission mode.

The Huisfit shipyard team has also reported that since this project, it is seeing an increasing interest in hybrid conversions. Owners and captains not only recognise the benefits in terms of on-board comfort, but also anticipate the requirements of future worldwide environmental regulations.

This vessel really is the ideal asset for many owners – a beautiful, classic sailing yacht that is also green and futureproofed; not many exist. So what does the industry have to do to make this refit/rebuild process more appealing to current owners?

“The hybrid conversion offers owners much more versatility and possibilities, amongst others more range and more

“A refit such as this very much suits visionary owners and captains who, like the owners and captain of Juliet, also acknowledge and embrace the great benefits of a hybrid conversion.”

Juliet on the hardstand during its refit.

Photo: Huisfit

Juliet’s hybrid controls.

available power,” says Coronel. “Despite the various additional options, the system must, above all, remain simple in order to make the end result attractive for the owners.

“A refit such as this very much suits visionary owners and captains who, like the owners and captain of Juliet, also acknowledge and embrace the great benefits of a hybrid conversion. Prior to a conversion like this, it is important to properly define both the current and the anticipated sailing profile so that a tailored corresponding system can be developed.”

Coronel explains that the process wasn’t all plain sailing for the refit team. As with any large-scale refit project, there’s inevitably going to be at least one issue arising that means either the strategy or the timescale of the job needs to be adapted.

“Some initial problems, such as cooling and limited power, could not be solved right away,” reveals Coronel. “We started testing the solutions for these problems extensively before integrating them as an improvement.”

The keel was laid for Juliet almost 35 years ago, and some of the original build team, who were junior engineers at the time, are now the senior managers who were responsible for its conversion. This combination of heritage and experience meant that the conversion of Juliet could be carried out without deliberation and concern.

Coronel concludes, “In the past years, the shipyard team has gained a lot of experience with hybrid systems, for example during the construction of Ethereal [the world’s first hybrid superyacht] and NextGEN ketch Elfje. The team’s experience with those two yachts was directly applied to Juliet’s conversion project.

“During the refit of Juliet [when the keel was also replaced] the larger part of the vessel turned out to be still in perfect shape thanks to the execution and quality that back in the day were already of a high level. This made a financial investment and the effort worthwhile. Post-refit, Juliet is still a beautiful classic and state-of-the-art yacht which, thanks to the modern hybrid system, can sail on for many years to come. She is now ready to sail into a greener future.” MS