Renk launches hybrid system for two-stroke engines


Propulsion technology specialist Renk is to launch a hybrid concept that enables two-stroke engine users to harness the electrical potential of their engines for either propulsion or power generation.

The MARHY (marine hybrid) system features a tunnel gearbox and propeller shaft clutch enabling the two-stroke engine to be connected to an electrical motor. The electrical package includes an asynchronous motor, active front end frequency converters and couplings.

MARHY can be used with both fixed pitch and controllable pitch propellers. In combination with energy storage, the system offers four operational modes: main engine propulsion with power take out to supply onboard electrical demand; main engine propulsion with power take in, to provide an electrical boost to propulsion; fully electric propulsion with the main engine turned off; and main engine as generator with the propeller disengaged.

The system offers fully redundant propulsion fulfilling class requirements including Bureau Veritas’ AVM-APS and Lloyd’s Register’s PMRL. For passenger vessels, this means that MAHY satisfies safe return to port requirements while for tankers, containerships and crude oil carriers the redundancy allows hazardous cargos to be transported in restricted areas.

The system, which is available for propeller shafts with diameters of 250-850mm, can also be used by ship owners to reduce the number of gensets deployed on a vessel, either by generating electricity for storage in a battery or through enabling the main engine to be used as a generator.

Motor ship