Azimut Yachts, the Italian shipyard noted for luxury yachts, revealed its Azimut Grande 140 Trideck with a new Rolls Royce propulsion system at the 2012 Cannes Boat Show in September. With an overall length of 42 meters (138 ft) and displacement of 276 tons (280.4 tonnes), this is the largest Azimut Grande model ever built and is the first vessel to feature the Rolls Royce Carbon Azipull 65C propulsion system with fully steerable pods.
The Azimut Grande 140 Trideck is a fast yacht intended for the Mediterranean market and carries seven crew and twelve passengers at a maximum speed of 21 knots (24 mph, 39 km/h). It’s built around a glass-reinforced plastic (GRP) Displacement to Planing (D2P) hull with a "Wave Piercer” bow to cut through the water and a hull tunnel to improve water flow over the propellers. Speed and performance of the design was verified using virtual 3D simulations and tank tests at the Brodarski Institut in Zagreb, Croatia.
The upshot of all this is that the Azimut Grande 140 Trideck hull has aspects of both a displacement and planing hull, which Azimut claims allows it to operate more efficiently than a displacement hull of the same length. It also shows a significant reduction in wave resistance, which results in better fuel efficiency and increased cruising range.
The Azimut Grande 140 Trideck is, of course, a luxury yacht, so Azimut Grande puts a great deal of emphasis on the exteriors designed by Stefano Righini and the interiors by the British yacht design firm Redman Whitley-Dixon, which are based on “Land, Sea and Air” concepts. This means lots of sun-bleached wood, elevated surfaces and paneled interiors over its three decks, along with the inclusion of two Jacuzzis and a fold-down stern complete with swimming deck and a bar.
What makes this hull possible is the Rolls Royce Carbon Azipull 65C propulsion system. The hull itself was designed to develop the best hull shape for the Rolls-Royce propulsion pod and a lot of work went into making sure that the propulsion pods and the hull are hydrodynamically compatible.
The Azipull 65C is an azimuth thruster propulsion system. Instead of a conventional propeller sticking out the stern, the propellers sit in pods sticking down from the hull. Each pod can be steered through 360 degrees, providing optimal maneuverability at high and low speeds and during docking maneuvers – all without the need of a rudder.
The pods are of carbon composite construction with a “twisted” profile for improved hydrodynamic efficiency, and a fin for greater course stability. Specially designed for fast Mediterranean yachts, it’s made to be lightweight, highly efficient and with very low noise and vibration levels. The carbon composite construction reduces weight by about 50 percent compared to metallic versions.
The Azipull 65C consists of two parts. There is the 1,150 kilogram (2,535.3 lb) inboard part with the upper bevel gearbox, the azimuth bearing and steering rams, and the 1,650 kilogram (3,637.6 lb) underwater pod comprising the lower gearhouse with bevel gear transmission, shaft seal and pulling propeller. These are connected by a flange that is designed to snap the pod off without compromising the integrity of the hull in the event of a grounding.
The propulsion system has a rated power of 2,000 kW at 600 propeller rpm and is designed to be installed in one piece. Each pod can be steered independently, so bow thrusters aren't needed. They can be set for a number of different comfort or green running modes and a simulator has been developed for training crews.
The Azimut Grande 140 Trideck is scheduled for delivery in 2015.
Sources: Azimut Grande, Rolls Royce Marine
Update: This story was amended on Dec. 11, 2012, to correct the weight of the two parts of the Azipull 65C.
