Parallel Hybrid: Diesel + Electric Motor with Generator Power

This parallel hybrid system is capable of generating electricity for hotel loads. It’s most suitable for vessels with long waits between jobs (e.g., tugs, pilot boats, workboats in general, military vessels, and yachts), and for those operating in restricted areas and zero-emission zones. Twin Disc technology enables implementation into any standard marine transmission.

High Voltage

Data / Command Signals

System Overview

  • Parallel hybrid using diesel and electric power
  • During low-power operation, the e-motor can use excess diesel power to generate electricity for hotel load, allowing the hotel load generator to be shut down
  • In high-demand phases, electric power can boost diesel power

Marine Transmission

  • Based on standard marine transmission, with same footprint and selection criteria, for worldwide support
  • No trailing pump needed; transmission is lubricated as diesel or e-motor drives it
  • Efficient design minimizing losses


  • Provides power generation through PTO/PTI in forward, neutral, and reverse
  • Prevents engine back-driving during electric-only operation
  • Allows all features of QuickShift® transmission

PTI Gearbox

  • Drives transmission primary shaft (same as engine) with MasterClutch™ providing disconnect
  • Allows for standard speed/smaller e-motor through motor speed reduction
  • Offset to propeller shaft enables installation of large motors
  • Reductions from 1.0:1 to 2.5:1
  • Integrated sea water pump cools transmission during electric propulsion
  • PTO available for onboard hydraulics (e.g., steering pump)

Propulsion Controller

  • Twin Disc standard propulsion controller and operator interface

Hybrid Controller

  • Manages power distribution, interfacing with propulsion controller and high voltage equipment

E-Motor/Inverter, High Voltage Equipment

  • Selection based on application characteristics
  • Controlled and monitored by hybrid controller

Profitable. Sustainable. Powerful.

These innovative hybrid and electric systems support greener power transmission while delivering the reliability you expect from Twin Disc. Explore some of Twin Disc’s hybrid and electrification options, then contact our team of experts to learn about the endless custom solutions available to create the optimal system. With more than a hundred years of experience in the design of innovative power transmission products, Twin Disc understands your needs and delivers the solutions that earn your confidence.


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Twin Disc specialists are available to work with your technical experts to select the optimal configuration and components for your specific application.

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