The Princess R35is a boat with a new foil systemand strong stylistic references to the automotive world
by Luca Sordelli – photo by Quin Bisset
THE R35STEMS FROM COLLABORATION BETWEEN PRINCESS YACHTS,Ben Ainslie Racing Technologies (a group of boating experts working with Great Britain for the America’s Cup), and Pininfarina, an Italian design studio. The boat was built with innovation and revolution at the top of the agenda, combining a modern design with a high-quality build and advanced technology to offer a completely new experience. The exterior was designed by Pininfarina,and the design firm harked back to its origins for the project, concentrating on the obsessive focus on aerodynamics of its founder, Battista “Pinin”Farina, responsible for shaping the company’s DNA, based on a pure and elegant style geared towards speedand performance.
Paolo Pininfarina said: «With the R35 we wanted to convey pure excitement, with a capital E. The excitement experienced by a child the first time he sees an aeroplane –that surprise at seeingsomething unknown combined with amazement at its beauty and power. The R35 embodies these three factors: a cutting-edge yacht with an extraordinary skin and the heart of a sprinter».
Just like a sports car, beauty always has to go hand-in-hand with function. Following this approach, Pininfarina has used the latest computational fluid dynamics technology to create and optimise shapes that are modelled by the wind, and has introduced air intakes in the hull. Their purpose is twofold: functional, because they take in air for the engines and expel it, eliminating vortices at the stern and thus improving aerodynamic performance; and aesthetic, as the wings that cover the intakes form the boat’s topside, becoming the distinctive feature of the design and creating a new icon in the process.
The hull is equipped with the Princess Active Foil System (AFS), designed by the Plymouth-based shipyard alongside engineers from BAR Technologies and Pininfarina –people who know a lot about ‘flying boats’and foils and who have moved from the world of sailing to that of motorboats specially for the occasion. According to Princess’engineers, this solution not only reduces water resistance by 30%, thereby improving performance and fuel consumption, but also provides excellent stability.
The two carbon-fibre foils can adjust independently of each other by +/- 5 degrees, and their positioning is calculated automatically by the onboard computer, which measures the pitch, roll and heave acceleration from a high-resolution Inertial Measurement Unit.
The speed of the boat, enginerevs and the driving style are also taken into account –the latter is selected by the pilot using a mode selector at the helm. One of the major consequences of this for the pilot is the boat’s excellent lateral stability, even when tackling normal turns.The optimal foil position is computed 100 times per second, responding practically instantly to ensure comfort and safety for those on board.
Unlike other foil technologies, AFS does not bring the R35 out of the water, but instead regulates the keel angleand the handling of the boat to ensure the least resistance possible with the utmost stability. A lot of work has gone into keeping weight down in the boat’s build –the hull is made of 100% carbon fibre, and the traditional gel coat has also been removed, replaced by a special coat that managed to shave 300 kg off the total weight. Overall, the boat weighs 25-30% less than competitors of the same length.
The twin Volvo Penta 430 horsepower petrol engines give the R35a maximum speed of roughly 50 knots, and an efficient cruising speed of 25 knots. «Aside from the revolutionary technology, the look and design of the R35 is enough of a reason alone to make you fall in love with this yacht. One day all boats will be made like this», Antony Sheriff, Executive Chairman at Princess Yachts said.«The R35is a rare mix of extreme elegance and technology. Often design is a triumph of beauty over function or function over beauty. Princess has been able to develop a technologically game-changing yacht that is also stunningly beautiful. It is in every way a new experience, yet also instantly recognisable as a Princess».
IMPRESSIONS AT SEA
Leaving your moorings is very straightforward, the Volvo Penta joystick and the bow thruster make it all very easy. The two AFS wings stay hidden inside the hull until we reach six knots, at around 1,000 rpm. Then they come out and you can feel the difference. The effect it produces is of gluing the boat to the water.
The T-shape of the two wings (which are 60 cm long) create a “tunnel”between the hull and its two wings which are parallel to the water surface. When the trim changes, the AFS tilt five degrees in all directions. The main aim is stability, and safety. So, then the first thing that you feel is actually a surprising degree of longitudinal stability.
You don’t notice the transition from displacement to planing mode, and it doesn’t go very nose up. But the best of it comes when the speed increases, the bow-stern trim is always perfect and gives a great feeling of security to whoever is helming –you get a nice sense of having “talons” gripping the water in the stern.
It feels as if you are running on rails even during high speed turns. You can choose between two modes, Comfort and Sport. In the first of these two, the AFS do all the work (they adjust a hundred times a second), and in the latter you can make your own adjustments to the boat trim.
Using the Comfort mode, and heavily loaded (six people and 90% of the liquids on board) we reached a top speed of 41 knots. In Sport mode, raising the trim, we reached 44.6. Getting to the very top speed of 48/50 knots with an empty boat seems plausible. Fuel consumption isn’t bad considering that you have as much as 860 hp available: at 4750 rpm and 35 knots, which is cruising speed, the two Volvo V8s use 168 litres an hour; whereas at economy cruising speed, 23 knots, that figure falls to 75 litres an hour. The acceleration is excellent: in five seconds you start planing, and in 23 seconds you get to top speed (in Comfort mode).
PROJECT: Concept Princess Yachts – Naval Architecture Ben Ainslie Racing Technologies – Design Pininfarina
HULL: LOA 10,89m •Maximum beam 3.27m – Draft 0.76m • Light displacement 4,500 kg- Full load displacement 5,900 kg • Fuel tank volume 600 l • Water tank volume 140 l
MAIN PROPULSION: Volvo Penta Petrol V8 (2×430 hp)
EC CERTIFICATION: CAT B
Princess Yachts Limited
Newport Street, Plymouth, Devon
United Kingdom PL1 3QG
Marine Group – Princess Yachts Italia
Portosole Via del Castillo 17
I-18038 Sanremo (IM) +39 0184 990770