Azipull Technology Debuts on Offshore Vessels

Havila is set to retrofit its supply vessel Havila Tampen with a pair of Ulstein Aquamaster Azipull azimuth thrusters for main propulsion, replacing conventional azimuth thrusters. The Azipull azimuth thruster from Rolls-Royce uses a pulling propeller ahead of the streamlined leg and lower gear house, and a simple gear drive transmission. The units for Havila will be the largest built to date: type AZP120 designed for inputs up to 3,000 kW, but in this case each transmitting 2,500 kW.

"We have chosen to pioneer this new propulsor in offshore service because we believe that it will give us significant fuel savings — in the region of seven to eight percent compared with traditional thrusters — through its improved hydrodynamic design, with a minimum of noise and vibration," said Robert Welsvik, managing director of Havila.

Havila Tampen is a UT-Design type UT745E boat that was delivered by Kleven Verft in September 2002. The vessel uses diesel-electric propulsion and the two Azipull units under the stern will be powered by electric motors in the hull. Conventional thrusters from Rolls-Royce were installed to get Havila Tampen into service. However, the owner had decided in principle to change to Azipull units as soon as these were released for offshore service, and this has now been confirmed. The changeover is designed to be quite simple. The existing propulsion motors and the input gear units in the hull can remain in place, and only the outboard parts of the main thrusters need to be exchanged.

The first Ulstein Aquamaster Azipull thrusters to enter service will be four AZP085 units propelling the first innovative new Fjellstrand FerryCat catamaran double-ended ferry, now under construction, which is scheduled to start operating on a route in the Stavanger region of Norway this summer. The thrusters have been shipped, and Rolls-Royce has orders for another two shipsets (eight units) for two more FerryCats to be built for operation in Turkish waters.