Page 49: of Maritime Reporter Magazine (March 1995)

Schottel Pump-Jets are used both as maneu- vering drives and for main propulsion. 162 ft. (49.5 m) long and 30 ft. (9.2 m) wide with an 11.1-ft. (3.4-m) draft. The vessel is designed to work primarily in coastal areas, and the independent maneuvering

Schottel bowthruster unit is viewed as a crucial safety element. The unit, in es- sence, helps eliminate the safety risk should there be a failure of the main propulsion plant. This safety element also applies to failure of the steering gear or a jammed rudder. Even in these ex- treme scenarios, the Pump-Jet can main- tain the safety of the ship and crew.

The main engine on theiVo. 3 Tetsuryu-

Maru is rated at 735 kW, and a maximum speed of 11 knots was achieved during sea trials. On the Pump-Jet alone, the motor coaster can reach a speed of approximately lllll knots.

The Schottel unit — which develops 194 kW at an input speed of 1,469 rpm — is installed flush with the shell below the ship's bottom, eliminating the risk of air being drawn in when the vessel is par- tially loaded or during pure ballast trips.

Another motor coaster in the Japanese market fitted with the Schottel Pump-Jet as a bowthruster is the MSSumiho-Maru.

The ship was built at the Kegoya Dock Co.

Ltd. for shipping company Sumiho Kisen

Ltd., and is similar in dimension to the

No. 3 Tetsuryu-Maru. To date, four ships featuring the Schottel Pump-Jet as bowthrusters have been put into service in Japan, with an additional two ships under construction.

How It Works

The Schottel Pump-Jet is an azimuthing propulsion unit. It works on the principle of a horizontal centrifugal pump. Water is drawn in from underneath the vessel, pressurized in the jet casing and expelled again at an angle of 13 degrees through three symmetrical nozzles in the bottom plate.

The thrust can be steered in any direc- tion, since the bottom plate with its inte- grated nozzles is able to rotate 360 de- grees. A protective grid in front of the intake prevents stones or flotsam from entering. For ice operation, Schottel has developed — in cooperation with the Ger- man shipbuilding research institute HSVA — special ice grids which prevent lumps of ice from being sucked in. The Pump-Jets can be driven by electric motors, diesel engines or hydraulic motors.

For more information from Schottel

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March, 1995 85

A FORC

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