Major advantages at a glance

• Environmentally friendly design with water-lubricated bearing system
• Significant noise and vibration reduction
• Significantly reduced space requirements
• Reduced weight
• No dynamic sealing needed
• Exceptionally high dynamic performance of the thruster
• Optimized thrust to input power relation
• Outstanding DP performance
• Customized thrust characteristics for forward and astern operation
• Unique propeller blade design for significantly reduced cavitation risk
• Low-maintenance system
• Easily replaceable composite (CFRP) blades
• 360Azimuthing / Steering control

Diesel Electric Propulsion

• Lower fuel consumption
• Better load sharing between the diesels due to multiple use of the power plant
• Simple layout of machinery spaces
• Improved smooth running, less vibration and low noise levels
• Reduction in maintenance costs - a major advantage of diesel electric systems is that the diesel engines can be made to operate at their design optimum power and generally installed within one area of the vessel.

For ships with a rather constant speed, such as container vessels running 90% of the time at cruising speed, the classic diesel direct propulsion provides a very good solution because the propulsion drive train can be optimized to this point of operation.

With yatchs with a varying speed profile optimizing a diesel direct propulsion still can be done but a large portion of the operating time the yatchs will sail in a non optimized operation point. Operation below 40% will lead to excessive fouling of the diesel engine and with that to higher maintenance costs. Further the specific fuel consumption increases when a diesel engine is not operating in its “sweet spot”. In fig 2 a general shape of specific fuel consumption is given for diesel engines.

By introducing diesel electric propulsion the negative effect running at non optimized operation points can be reduced, resulting in better fuel economy. At low speeds a number of diesel generators can be turned off which will lead to a higher loading on the remaining diesel generator sets.

Diesel electric propulsion provides flexibility in layout of the ship, avoids low loading of diesel engines, provides more reliability in operation, is beneficial for the environment and enlarges the maneuverability capabilities of the ship. So diesel electric propulsion provides modern alternative propulsion with high maneuverability and efficiency.

Fuel consumption can be minimized by choosing optimum genset configuration, according to hull resistance characteristics of ship.

A Revolutionary Propulsor System

Creating a thruster system that offers the ultimate in comfort without compromise in performance was our driving motivation. Using the latest technology, Voith developed this state-of-the-art rim drive system: Voith Inline Propulsor (VIP).

The steerable Voith Inline Propulsor (VIP), combined with a nozzle, is designed as a main propulsor or assist system for DP or tracking modes, while providing the highest comfort-class criteria.

General specifications

The Voith Inline Propulsor systems are driven by an integrated permanent magnetic (PM) synchronous ring motor.

The motor windings are housed in the stator, the permanent magnets are housed in the rotor. The rotor is supported by water-lubricated bearings for the radial and axial load. The propeller blades made from Carbon Fibre-Reinforced Plastic (CFRP) are directly connected to the inner ring of the rotor, which eliminates the need for a central shaft or gearbox. The sense of rotation, as well as the speed, is controlled by frequency converters.

Thruster housings are pressure-tested to verify water tightness and are filled with resin to encapsulate all electric parts and permanent magnets.

Blades

The fixed pitch blades are made from Carbon Fibre-Reinforced Plastic (CFRP). Each blade, employing a special coating system, is individually replaceable and highly resistant to cavitation.

Power and monitoring cables Voith uses high-performance underwater cables and connectors for the monitoring as well as for the power supply of the thruster systems.

Performance

Exceptionally high dynamic performance. PM motors deliver high torques – even at low revolutions. High acceleration in combination with instant thrust values increase the dynamic behavior of the vessel. VIP thruster is designed for optimum thrust in its preferred operating direction.

Reduced noise / Vibration emissions

The unique design of the VIP results in significantly reduced noise and vibration emissions. With conventional propellers there are two key reasons for noise:

• The propeller tip clearance, i.e. the distance between hull and the tip of the blades
• Shaft-induced cavitation due to the support structure

Both elements are not present in the VIP design, therefore noise and vibration emissions are greatly reduced.

Less installation space

New compact azimuthing propulsion system requires significantly less installation space without any other propulsion elements outside of the engine room such as Shaft, P-Bracket or Rudder.

Test facility – FAT

Voith tests all propellers under realistic conditions by using an in-water test facility. During factory acceptance tests, thrusters are operated per classification rules in real conditions. The test program includes verification of thrust performance, thermal behavior, endurance, insulation, and high voltage test.