ROLLS-ROYCE Marine is about to promote its Ulstein Aquamaster azimuth thrusters to the fishing industry for both newbuildings and refits.

They have been practically standard equipment in the offshore industry for some years.

The thrusters are fitted amidships or forward in the hull and are dropped into the water to operate in any direction. In the retracted position they can work as a powerful tunnel thruster.

"There are several advantages with this type of equipment, " Kjell-Olav Kleppe, director of sales and marketing in the fishing division, tells FNI.

"Purser-trawlers in particular could use azimuth thrusters effectively. These vessels spend long periods searching for marks or other activities at low power consumption, but need substantial power for trawling.

"Instead of having a single large main engine that operates for long periods on low loads, with an azimuth thruster these vessels could have a smaller main engine and use the thruster to add to their towing power when needed, " he explains.

He says that the engine size of these combination-type vessels is constantly increasing, along with the size of the whole propulsion system including the gearbox and propeller. This increases the vessel's draft to accommodate the large propeller.

"For vessels like these a smaller engine and an azimuth thruster could meet all of their needs and eliminate the need to have a large engine running a lot of the time with a small load.

"We estimate an increase in towing power of between ten and 20 per cent with this arrangement compared to a conventional propulsion system." Normally an electrically-driven azimuth thruster can also be diesel-powered, if required, and in the swing up version can be delivered from 880 up to 3000 kW.

"This is already proven technology, " Kjell-Olav Kleppe tells FNI.

"We have supplied hundreds of azimuth thrusters to supply vessels and coastal ferries.

Anchor-handling tugs use them and they have worked well on advanced offshore vessels, so we feel that they have their place in the fishing industry as well."

Rolls-Royce also sees fitting an azimuth thruster as a cost effective solution for an existing vessel in need of increased towing power.

"This is an option instead of replacing the entire main engine, shaft, propeller and gearbox. An azimuth thruster can increase the towing power of a trawler efficiently and we have already had interest from Norwegian operators, as well as from Russia. "In Russia there are a great many older vessels in need of increased towing power and this could be the most cost effective way of increasing their bollard pull."

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Thrusters increase towing power