OSS – In a nation of boat builders with roots dating back a century or more, Heesen Yachts is a rookie, 59 years shy of its centennial. But it has a solid reputation for making very advanced, very fast yachts. And none shows that better than its 80.7m (265ft) Project Cosmos.
Heesen’s largest, most ambitious project ever is bound to solidify its grip on the market for highly customized aluminum and steel yachts of 40 to 80m (131 to 262ft.). But to get there, Heesen is jumping through very challenging hoops.
“Project Cosmos,” says CEO Arthur Brouwer, “is raising the bar once again. Not only for Heesen, but for custom aluminum yacht building in general. From a technical standpoint and from a performance point of view we are pushing boundaries. Not only has this 80.7m project been designed to reach close to 30 knots top speed, she has been designed for fast, 20+ knots cruising in an efficient manner.”
Cosmos _ it is the project’s name, not the yacht’s _ will use a development of the Van Oossanen Naval Architects’ Fast Displacement Hull Form. The project has forced Heesen and its partners to rethink construction methods and propulsion techniques. Ahead of the keel-laying, Heesen did much advance work with in-house design and engineering expertise and outsourced knowhow from Van Oossanen Naval Architects and Rolls Royce.
To ensure an 80.7m aluminum yacht retains stiffness _ not a minor concern in a yacht doing 30 knots! _ Van Oossanen developed a patented ‘Backbone’ construction model that preserves stiffness but adds no weight. This was extensively tank-tested. Combining a FDHF design and the Backbone method in a large aluminum yacht yielded a slightly deeper draft and a slim underwater body in the aft ship area.
Fortuitously, that improved performance and speed with comparatively low fuel consumption.
Rolls Royce worked on the propeller design and used its Promas system which integrates propeller and rudder into one unit to optimize hydrodynamic efficiency. A special hubcap will be fitted to the propeller to streamlines the flow onto a bulb that is added to the rudder. This reduces flow separation behind the prop whose design was fine-tuned to ensure speed and efficiency and eliminate potential cavitation problems. Cavitation occurs when air bubbles form behind a propeller causing noise and vibration.