Jet pack: Putting the water-jet propelled Vespro 55 dayboat to the test off the port of Cannes

The Vespro 55 uses next-gen water jets to hit a top speed of 56 knots. Risa Merl holds on tight…

Surging out of the port of Cannes, eventually building up to a cruising speed of 50 knots, the 16.5-metre Vespro 55 seems to skip along from one wave crest to another in a thrilling yet comfortable ride. With its optimised Deep V hull, bounding over the waves seems like child’s play for this go-fast dayboat. Of course, many yachts can go fast in relative comfort – what sets the Vespro 55 apart from the crowd is the wealth of technological innovations on board, from its weight-saving materials to water-jet propulsion, hidden within its highly efficient hull.

Launched by Italian yard Centouno Navi, the Vespro 55 is the first offering from this new Viareggio-based builder, and there are designs in the works for three larger boats, ranging all the way up to the 38-metre Eterea model. While this brand might be newer on the yachting scene, the names behind Centouno Navi represent
a deep yachting heritage. 

The co-founder of Centouno Navi is naval architect Marco Arnaboldi, the son of designer Angelo Arnaboldi who founded Studio Arnaboldi in 1984. Then, in 1992, the Arnaboldi family started AB Yachts, known for its high-performance yachts achieving speeds up to 70 knots.

“In 2010, I left AB Yachts and decided to work as a naval architect, developing fast projects for many shipyards in Italy, such as Sanlorenzo, Pershing and ISA,” says Marco Arnaboldi, who has worn many hats in the yachting industry, including boatbuilder, naval architect, designer, marine technology researcher and even water-jet dealer, partnering with Marine Jet Power. “When the shipyards need speed, they call us.”

Arnaboldi got the urge to build boats again under his own banner and co-founded Centouno Navi with fellow Italian designer and childhood friend Manuela Lucchesi in 2020. Together, the two designers created the Vespro 55’s exterior and interior, while Arnaboldi took the helm on the naval architecture. 

“Other projects were for other shipyards, and sometimes they were shy of innovation and new technical solutions so were often only partially building what I was designing for them,” says Arnaboldi. He wanted to push the envelope, and in the case of the Vespro 55, this means designing a dayboat with water-jet propulsion.

While water jets have been around since the 1950s, the technology has vastly improved since its inception. With this propulsion solution, water is pulled from beneath the hull of a vessel and forced through a nozzle to create a powerful jet stream from the stern, propelling the boat forward at great speeds. 

Other pros to water jets include low noise and vibration, and, as the propulsion system is inboard with no propellers, there’s a reduced draught. “Water-jet propulsion is less dangerous compared to propellers, which are a risk for marine animals,” says Lucchesi.

So, with all these pros, why aren’t more builders using water-jet technology in this size of boat? One of the cons is that building a boat with water jets can be a finicky process when compared to traditional propulsion. Small changes, such as increasing the jet size or changing a gearbox, can result in disaster, from a build perspective. “Water jets are a very delicate machine and if you miss some detail or make a mistake you have to basically throw the boat in the trash can,” says Arnaboldi.

Another hangup is that in the past water jets were considered difficult to manoeuvre. But in 2000, Studio Arnaboldi, along with Marine Jet Power, helped to develop a joystick control for water jets to make them more user-friendly. With a deep understanding of this tech and a no-holds-barred attitude to implementing it on his own designs, Arnaboldi seems to be well poised to re-invigorate water jets on board the Vespro 55.

The Vespro 55’s efficient deep-V hull form reportedly requires 10 per cent less power, compared to similar size boats, to reach a top speed of 56 knots. Cruising speed is a notably fast 50 knots, and when moving at a slightly more sedate pace of 30 knots, the Vespro 55 only consumes six litres of fuel per nautical mile. 

With a company slogan of “Fast is green”, the builder also notes that the Vespro 55 produces 50 per cent less CO2 than other boats in its class thanks to this fuel conservation. “One litre of fuel produces 2.7 kilograms of CO2; this is a standard combustion process for every boat, but since we burn only six litres per nautical mile, that’s less than 20 kilos per mile,” says Arnaboldi.

Part of this is down to the lightweight materials selected for the Vespro 55, which include a recyclable PVC foam. “The PVC foams we used on board are recycled, as are other materials we use for construction,” says Lucchesi. A variety of recycled and recyclable materials were also selected for the interior. 

The largely white decor is punctuated by high-gloss wood and black reflective panels, which give a nearly futuristic feel to the minimalist-glam decor. It was a purposeful decision to use less wood on board and to choose joinery that is itself recyclable. The builder also developed a patent-pending vertical windlass system that ekes out more space in the interior, giving the owner’s cabin an additional linear metre.

Every element of the Vespro 55 seems aimed at improving efficiency, even the sleek exterior lines. “The dynamic air intakes, for example, are integrated into the roll bar,” Lucchesi notes.

Promising performance, speed and efficiency, it’s safe to say that Centouno Navi has entered the yachting market on a high.

First published in the October 2024 issue of BOAT International. Get this magazine sent straight to your door, or subscribe and never miss an issue.