Advanced shaft generator.

Turn your main engine's mechanical power into onboard electricity, and eliminate auxiliary generator dependency at sea. A variable speed shaft generator system is one of the most cost-effective retrofits available for existing tonnage.

270+
Vessels in operation
3
Operating modes
0
Extra bearings required

Main engine power, used twice.

A permanent magnet generator is mounted directly on the intermediate shaft between the main engine and propeller. As the shaft rotates, it generates electricity, feeding ship loads through a variable frequency drive and DC bus, without running auxiliary diesel generators.

The permanent magnet rotor mounts with minimal mass and inertia, avoiding impact on torsional vibration calculations. No additional bearings are required for two-stroke installations.

MAIN ENGINE SHAFT GENERATOR PROPELLER ME SG Perm. magnet AC → DC Variable Freq. Drive WE Drive™ technology DC BUS Bow thruster Accommodation Aux. systems

One system, three modes.

The shaft generator operates in the mode that best fits the situation — generating power under normal conditions, providing a safety fallback, or adding extra thrust when the main engine needs support.

PTO — Power Take Out

Economical generation

The shaft generator produces electricity directly from main engine rotation. Auxiliary diesel generators are switched off at sea, reducing fuel consumption and engine hours.

Best for: Normal sea passage

PTI — Take Me Home

Auxiliary propulsion

The shaft generator switches to motor mode and drives the propeller shaft if the main engine is unavailable. The vessel can return to port safely under its own power.

Best for: Redundancy & safety

PTI — Boost Mode

Peak power boost

The shaft generator adds motor power to the propeller shaft on top of the main engine, providing extra thrust in demanding conditions such as heavy weather or canal transits.

Best for: Heavy weather, canals


Measurable savings, from day one.

Generating electricity from the main engine instead of running separate auxiliary generators eliminates a major source of fuel waste. The result is lower operational costs, fewer running hours on auxiliary engines, reduced emissions, and improved EEXI and CII ratings.

  • Significant reduction in fuel consumption at sea
  • Reduced auxiliary engine running hours and maintenance costs
  • Lower NOx, CO₂, and greenhouse gas emissions
  • Improved EEXI and CII compliance
  • Quieter vessel — less vibration and noise from aux. generators
Energy source comparison WITHOUT SG Main Engine Propulsion only Aux. Generators ×2 Ship electricity 2 fuel sources running WITH SG Main Engine Propulsion Shaft Gen. Ship electricity (DC bus) Aux. generators — OFF 1 fuel source — optimised

From screening to sea.

Every retrofit starts with an operational profile analysis to confirm the business case. MHS manages the full scope, from survey and simulation to engineering and class approval through installation and commissioning, so the shipowner has one point of contact throughout.

1 Vessel screening Operational profile, compatibility, simulation 2 Onboard inspection Shaft measurements, space survey, system verification 3 Engineering & class approval Detailed drawings, torsional analysis, classification 4 Installation & commissioning Shipyard installation, sea trials, system handover 5 Digital after-service Miira monitoring, performance tracking, crew training

Works across ship types.

Variable speed shaft generator systems are suitable for both two-stroke slow-speed and four-stroke medium-speed main engine configurations, across a wide range of vessel types.

Bulk carriers & tankers

Long ocean passages with steady shaft speeds make bulk carriers and tankers ideal candidates. High fuel savings potential and fast payback.

Container & cargo

Variable speed shaft generator systems handle fixed and controllable pitch propeller arrangements across container and general cargo vessels.

RoRo & RoPax

Shore power connectivity and boost mode capability make shaft generators especially attractive for ferry and RoPax operators facing emission-free port requirements.

Is your vessel a candidate?

Send us your operational profile and we will assess the fuel saving potential and payback period at no cost.