With a low freeboard hull and impressively low noise levels, the architect’s first motor vessel is comparable to a sailboat, says Charlotte Hogarth-Jones
“Listen, what can you hear? You can’t hear anything, can you?” asks architect Renzo Piano as the 24 metre motor boat Zattera hits the water for the first time. “It’s whisper quiet,” he smiles, “and that’s what’s important.”
Just the wooden hull of the boat exists currently, at the Castagnola Yacht shipyard in Lavagna, Italy, and work is now about to begin on an impressive glass superstructure that will contain an office. The project is a collaboration between Piano – who has designed world-famous buildings including The Shard in London, the Centre Georges Pompidou in Paris, and the Whitney Museum of American Art in New York City – and the owner, Norwegian property developer Olav Selvaag, along with their wives, Emilia and Kristine. Design is by Nauta Design, who worked on Piano’s latest sailing boat Kirribilli II back in 2007, and which is now owned by the Selvaags themselves. The naval architect is Francesco Rogantin of NAMES studio, and Zattera also has a propulsion system developed by Siemens Energy.
The relatively light vessel has a displacement hull that reaches a maximum speed of 12 knots (cruising speed of 10.5 knots), and onboard there’s an owner’s cabin and two guest cabins in the bow area, with the galley, the crew area and the engine room aft. Featuring crisp, clean lines and unusual proportions – Zattera has a beam of 7.2m and has been called “the raft” (“Zattera”) – the boat is already striking, even in an unfinished state. “Well, I feel much better!” laughs Piano as she’s lowered into the water. “It’s been a long time coming.”
The idea for her came about five years ago, he explains, while himself, Olav, Emilia and Kristine were sailing in Sardinia. “Renzo had this idea of a project based around sustainability and moving in total silence,” explains Selvaag, “and then we’ve developed that over many years.”
The lack of noise was a key feature for them all, he explains. “It’s a good thing in a time when there are so many distractions.” A connection to nature was also a key factor. “We don’t look at it as a motor boat, more like a sailing boat where you have time to contemplate and just be in the elements,” explains Kristine. “It’s a true one of a kind.”
Selvaag and Piano have known each other for over 20 years, having collaborated together on a museum project in Norway. It’s been easy to agree on what they want for the boat, they explain, as they have a similar vision for the project.
“It’s really fun because we’re collaborating on what is important for each of us, and since we’re making it together, it’s going to be a boat that we all feel extremely comfortable in,” explains Kristine, describing how the four have regular board meetings (or, during Covid times, Zoom calls) to exchange ideas. “Who is the most lively? Probably Renzo,” she laughs, “he’s very enthusiastic.” They plan to use her together, “for recreation, maybe a little bit for work, a bit as a house,” explains Selvaag.
With a deck almost at sea level – Piano’s idea – walking on Zattera has been compared to walking on water. “It’s very simple, but the silence and being so close to the ocean – it’s the nearest thing to being on a sailboat,” says Piano. “And we are all sailors,” he adds, “we’ll never stop sailing.”
In fact, he goes on, it’s his favourite part of the boat – although he’s keen to point out it’s “not a yacht, it’s too small.” Being on deck is “like being on a flying carpet, you feel nothing,” he enthuses. “She’s slow and silent.”
Low noise levels onboard are largely due to the Siemens Energy hybrid propulsion system, which is powered by two 180kW variable speed diesel generators, and a 95 kWh lithium-ion battery pack. This connects to a 700v direct current distribution system, which powers both the propulsion and the other onboard utilities.
The propulsion consists of two traditional shafts driven by high-torque permanent magnet motors, each with a power of 135kW. The two diesel generators, meanwhile, were developed by Mase Generators for Siemens Energy with Volvo Penta D4-300 engines, and use permanent magnet alternators in order to minimize consumption and emissions. The generators are also installed on a double series of anti-vibration mounts – not common on a boat at the smaller end of the spectrum – while extensive research was done on what materials should be used to soundproof the generators and engine room. Work is also underway to obtain a silent submerged exhaust system.
As well as the lack of noise, Piano is passionate about Zattera’s wooden hull. “We have such beautiful pieces of wood,” he says, digging out pictures on his mobile phone. “It’s like being inside the belly of a whale!”
Piano’s original idea had been to build the boat in reinforced concrete, but in the end, wood became a more practical choice. “It’s lighter, very sustainable, and you know, it looks alright,” laughs Piano, who also has a number of wooden buildings currently in construction – amongst them is a new wooden skyscraper in Japan that’s over 100m tall.
He’s also excited to be building – and keeping – Zattera in this part of the world. “You’d normally do a project like this in the north of Europe where there’s very little sun, so doing this in the Mediterranean is different,” he explains. “You have double the sun and double the energy, so that makes a real difference – we have totally different options than we would in the north.”
Despite it being a collaboration, there are some trademark features that mark the project out as Piano’s – a recognisable Renzo mast for one.
“One of the things I like a lot about Mr Piano is that he doesn’t think technical elements need to be hidden. If you run a pipe, you can run a pipe, just do it in a good way,” explains naval architect Rogantin. Piano agrees. “I like to see how a building is made, and I like to see how a boat is made. I like to show this visually, otherwise everything becomes flat.”
There’s a sense that for all involved in Zattera, the project is something of an experiment – a continuous evolution between shipyard, architect, designer and owners, and one that all parties are keen to get just right.
“For sure – it’s fun, but Mr Piano adds innovative new ideas every week!” laughs Rogantin. “He sees the project as a workshop – swapping ideas, trying them, seeing if they work, then perhaps trying something else,” agrees Luca Pedol of Nauta. “It’s a great pleasure to work together,” adds Mario Pedol, co-founder of the Nauta studio. “He organises his thoughts and design procedures very differently to us, so it’s been very interesting. On this project, he’s really made his mark as the great architect he is.”
Those eager to see Zattera completed may have to wait some time. The battery system still needs to be finalised, as do the interiors, which will likely be “something very functional and clean,” says Selvaag. The aim is to have the boat finished ready for the summer season, but that’s by no means a hard deadline. “This project, it’s like a laboratory,” says Piano. “That’s why we’re not in a hurry. We will take our time.”