Rolls-Royce celebrates 50 years of azimuth thrusters (1965 – 2015)

Key facts:

May 2015 was the 50th anniversary since the first Aquamaster® azimuth thruster was delivered from the Rolls-Royce facility in Rauma, Finland.

1965 was the start of a product development that has grown in size and scope to become a major product line in today’s Rolls-Royce propulsion product portfolio.

Azimuthing thrusters rotate through 360 degrees, providing propulsion and manoeuvrability, without the need for a rudder. They are produced in Rauma and Ulsteinvik (Norway).

Raumaproduces the following types: UL, US, UUC, Contaz

Ulsteinvik produces: Azipull, Permanent Magnet Azimuth (plus PM tunnel thruster)

Over the last five decades over 8,000 Rolls-Royce azimuth thrusters have been delivered.

They are mechanical thrusters which are mounted below the waterline and can be driven either by direct drive from an engine and gearbox, or from an electric motor - within the hull of a ship or structure of a floating rig.

The UUC range are our largest and most powerful thursters. They are unerwater mountable and typically used on drillships and semi-submersible rigs, but also on vessels where high power is required, such as tugs, icebreakers and offshore vessels.

In May 2015 Rolls-Royce delivered its 1000th UUC underwater mountable thruster.

The largest UUC thrusters from Rauma are rated at 7.5Mw, and can weigh in excess of 75 tonnes.

The UUC range curently has a 70% market share for drillship propulsion.

History

Aquamaster® thrusters began as a diversification for the Hollming shipyard in Rauma, Finland. The yard had originally been established to build vessels as war reparations to the Soviet Union, and was looking for something to even out market fluctuations.

This first product was a steerable propeller with a deck-mounted diesel engine and installed on a hopper barge called Palko. It was largely made up from tractor and vehicle components.

For the first few years, production volumes were small, 2-10 units per year in sizes from 100-300hp.

As the export market grew, a good name was needed for the product, and it evolved over time to be known as the ’Aquamaster azimuth thruster’. Aquamaster® remains a valued registered trade mark of Rolls-Royce.

By 1975 thrusters were offered in four sizes from 100 to 800hp. The market outside Europe had grown as well, expanding to include the US, Canada and Japan, while sales volumes were growing rapidly.

It was clear that the market was interested in bigger azimuth thrusters. The problem was finding durable large bevel gears and the other components needed to handle the high powers.

So the R&D challenge was to overcome these difficulties, while at the same time raising the efficiency of azimuth thrusters above the level of conventional propulsion systems.

A significant advance came at the beginning of the 1980s with the design of the first unit to be rated at over 1,000hp. This was the Aquamaster 1250 which was renowned for not only for reliability and manoeuvrability.

The quest for greater efficiencies led to the Aquamaster CRP, an azimuth thruster with two contrarotating propellers close together - the aft propeller recovered swirl energy from the leading one. It was given the name Contaz, and delivered improvement in thrust and vessel speed and a decrease in fuel consumption.

The first Aquamaster azimuth thrusters with a power rating in exccess of 10,000hp were developed in the early 1990s, with the initial application being a very demanding one, ice-strengthened ARC 1 units. Two thrusters per ship were supplied to the multipurpose icebreakers Fennica and Nordica, providing both main propulsion and excellent manoeuvring in open water or thick ice. The two vessels are still operating in the same way today.

Over the years the Aquamaster business was restructured and enlarged several times, most significantly when it was merged with the Rauma Repola deck machinery business. The enlarged business was acquired by Vickers plc in 1995 and was combined with Kamewa propulsion products manufactured in Sweden.

This combination of experience led to the development of the UUC range of underwater mountable thusters, with the first being delivered for drill rig applications in 1998. These robust and reliable thrusters, designed primarily to operate in Dynamic Positioning mode can be removed and installed without drydocking the vessel.

Today they are fitted to over 70 per cent of the world’s semi-submersible drilling rigs and drillships.

From 2000 the thruster and deck machinery product lines manufactured in Finland and Sweden were integrated with other Rolls-Royce products manufactured in Norway. At a stroke the range of Rolls-Royce azimuth thrusters became the broadest in the buisness and development continued.

In 2002 the first Azipull (from Ulsteinvik not Rauma)units, a ’pulling’ azimuth thruster, entered service. Designed for maximum propulsive efficiency, with a hydrodynamically efficient shape, Azipull units are suitable for higher speed applications and for continuous service speeds of up to 24knots.

Two of the world’s largest floating structures are powered by UUC thrusters from Rauma:

  • The Pioneering Spirit, owned by Allseas, is an innovative heavy lift vessel which will be used for decommission oil platforms – 13 UUC thrusters power this twin hulled, construction vessel. It starts work offshore Norway this summer, decommissioning the YME facility.
  • Shell’s Prelude, the world’s first floating liquifeid natural gas production facility will feature three large UUC thrusters, for position keeping. The thrusters are installed in a novel arrangement that allows them removed and maintained within the ship.

These are world firsts for Rolls-Royce and illustrate the company’s leading position in the sector. On board Shell’s floating liquefied natural gas production unit Prelude, the world’s largest-ever floating structure that will operate off the coast of Western Australia,, three electrically-powered 5.2MW (6,975hp) USL 455 Rolls-Royce azimuth thrusters will ensure that the unit stays head on to the weather at all times.

Since the 600,000-ton Prelude is designed to remain on station 200km offshore and continue to produce and liquefy gas constantly for at least two decades, reliability and scope to service the azimuth thrusters at sea are vital. Each thruster is housed at the base of a shaft with its own dedicated crane linked to a workshop above, within the hull.

Another notable thruster installation has taken place on board the world’s largest vessel, the 403,342 gross ton Pioneering Spirit, a giant platform installation, decommissioning and pipe laying ship which is currently being mobilised in Rotterdam prior to deployment in the North Sea later this year.

In addition to a total 94MW of power generated from her nine main engines, no fewer than 12 Rolls-Royce UUC 455 thrusters, each of 5.5MW, will ensure that the Pioneering Spirit can remain accurately on station at all times. She has the highest grade of dynamic positioning notation, DP3.

Meanwhile, at the other end of the scale, relatively small azimuth thrusters enable harbour tugs to turn on their own axis. As integral components of highly sophisticated dynamic positioning systems, they also enable the precise station-keeping of a wide range of offshore vessels including anchor-handlers, wind turbine installation ships, pipe- and cable-layers, seismic survey ships and offshore accommodation vessels

In May 2015 Rolls-Royce delivered its 1000th UUC underwater mountable thruster. It is the third unit in a series of six being installed on Seadrill’s new mobile drilling ship currently under construction at Samsung Heavy Industries in Korea

Permanent Magnet technology

PM Azimuth Thruster

Rolls-Royce launched a new azimuth thruster powered by permanent magnet (PM) technology developed in Ulsteinvik, at Nor-Shipping in Oslo in June 2015.

The launch followed a programme of sea trials place on board the RV Gunnerus, the Norwegian University of Science and Technology’s (NTNU) research ship, based in Trondheim.

On trial a pair of thrusters demonstrated efficiency savings of 7-13% depending on ship speed, and in comparison to azimuth thrusters powered by a conventional diesel-electric system.

Each PM azimuth thruster comprises three main assemblies – the PM motor/propeller/nozzle underwater unit, the hull mounting system which includes the azimuth bearing and duplicate frequency controlled electric steering gear, and the inboard power unit which feeds electric power to the thruster.

The permanent magnet motor consists of two main parts – a stator that carries a number of electrical coil windings, and a rotor fitted with a number of very strong permanent magnets.

A rotating magnetic field is created by the stator which interacts with the fields of the permanent magnets on the rotor, which generates force to drag the rotor around, providing the mechanical power.

The PM azimuth thruster will remain on sea trial aboard the research vessel Gunnerus throughout 2015.

For further information including pictures, please contact:

Craig Taylor
Head of Communications – Marine

Rolls-Royce

m: +44 (0) 7807 969 426
e:

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