Along with Svitzer of Denmark, Schottel said it has developed a new hybrid propulsion concept that makes it possible to drive two thrusters with either one of the main engines.
The new concept, called SYDRIVE-M, is based on the recent Schottel Y-Hybrid thruster technology and connects a port and starboard mounted azimuth thruster in a vessel with each other. The companies are now discussing a pilot project to retrofit an existing tug with the new mechanical hybrid technology.
Svitzer runs a fleet of 430 vessels and has operations all over the world. Thomas Bangslund, group head of Innovation at Svitzer, was closely involved in the development of the synchron-mechanic hybrid drive system.
The companies said that common vessel operation profiles for tugs or workboats include up to 90% of operation time with low engine loads. To optimize propulsion systems for such load, conventional hybrid propulsion systems come with two independent power sources per propeller, normally configured with a main engine and a smaller electric motor. Those additional electric components make those hybrid concepts more complex and more expensive.
Based on the Schottel SRP-Y Hybrid upper gear module for azimuth thrusters, the Schottel SYDRIVE-M is a new variable and purely mechanical hybrid propulsion system with no need for any additional electronic components or an additional gearbox.
The core functionality of SYDRIVE-M is to mechanically connect two thrusters and one of the two main engines for all light operation activities which do not require full power of the two main engines. In this synchronized Light Operation Mode, one of the two main propulsion engines remains alternating off. This leads to a noticeable reduction of operating hours of the main propulsion engines, and thus to a reduction of maintenance costs, the companies said.
In addition, the single running main engine remaining in operation is now better loaded by two thrusters and operates in a better specific fuel consumption range, leading to less fuel consumption and emissions, according to the companies. In contrast to a conventional tug, with two engines running in traditional Light Operation Mode, where both engines are operated at a relatively low rpm range which is not efficient with regard to fuel consumption and emissions.
For short operation times when full propulsion power is needed, the connection between the two thrusters is disengaged and each engine is engaged to each thruster. The system is now identical to any other directly driven propulsion system.
For any directly driven vessel the new SYDRIVE-M system provides a solution to enable fire-fighting operation with no need of an additional investment in components like medium or heavy duty slipping clutches, CP propellers or dedicated engines to supply power to a FiFi-pump, the companies said. For the SYDRIVE-M FiFi-mode, the disengaged main engine is used to drive the FiFi-pump through its front PTO.
SYDRIVE-M can be integrated into any usual vessel design with direct propulsion with no need of design changes. It is available for the Schottel Rudderpropeller and EcoPeller series of azimuth thrusters from 1000 kW up to 3000 kW. Retrofit is possible upon request for specific Schottel azimuth thrusters and engine types. The system has been filed for patenting.