Hybrid Drive Systems

Operation profiles of tugs and workboats feature low engine loads for up to 90 percent of operation time. In such instances, an engine that is rated for maximum propulsive power works in an unfavourable partial-load range that is inefficient in terms of emissions and fuel consumption. Hybrid drive systems are predestined for applications with highly variable power ranges. These generally consist of two separate power sources (diesel and/or electric motors) per propeller with different power ratings. SCHOTTEL has further extended the system to a broader understanding of hybridization with SYDRIVE-M.



Thanks to the combined or sequential use of combustion engine and electric motor, SYDRIVE-E with its extensive and intelligent operating modes enables efficient energy and thrust generation in many different operating conditions. A unique feature is the flexible configuration of power input positions, which allows the drive train to be designed in various manners. This provides greater freedom when designing a vessel and ensures that the individually available installation space can be used optimally. Three power input positions for a ±90° or ±135° installation angle form a Y-shaped arrangement. The individual power inputs are not subject to any power limitation which means that any arrangement of primary and secondary input with variable load distribution can be realized.




  • SIMPLE | Hybridization of SCHOTTEL azimuth propulsion units from 400 to 2,600 kilowatts in vessels of all types and sizes
  • VERSATILE | Three power input positions for an installation angle of ±90° or ±135° for two power sources
  • SCALABLE | Retrofitting with SCHOTTEL azimuth propulsion units possible for existing vessels
  • ADAPTABLE | No modifications required in the drive train
  • PROVEN | SCHOTTEL quality and experience, and high availability



SCHOTTEL SYDRIVE-M is a variable and purely mechanical hybrid propulsion system with no need for any costly additional electronic components. The concept 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. They can be driven together by only one of the main engines.




  • SIMPLE | Purely mechanical system without additional electrical components or additional gearboxes
  • ADAPTABLE | No modifications required to the ship design
  • COST-SAVING | Reduced engine operating hours for lower maintenance costs, less fuel consumption and fewer emissions
  • FLEXIBLE | Suitable for new constructions and retrofits in existing vessels
  • VERSATILE | Available for SCHOTTEL SRP and SRE
  • PROVEN | SCHOTTEL quality and experience, and high availability



Based on the unique SCHOTTEL SRP-Y Hybrid upper gear module for azimuth thrusters, SCHOTTEL SYDRIVE-M is a variable and purely mechanical hybrid propulsion system with no need for any additional electronical components or an additional gear box. This system comes with many advantages as noted in the three following main operation modes: 

Light Operation or Free Sailing Mode

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.

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. 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.

Full Thrust Operation Mode

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 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. For the SYDRIVE-M FiFi-mode, the disengaged main engine is used to drive the FiFi-pump through its front PTO. 


In action