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The perfect GenSet across your fleet

By applying innovative technology combined with classic design principles, the MAN L23/30H Mk3 GenSet is built to meet your needs for today and for the future. With an exceptionally wide power range of 500kW–1800kW, including the new 9-cylinder unit version, the MAN L23/30H Mk3 GenSet is suitable for almost any vessel type in your fleet.

An updated 500 kW-1800 kW power range makes this GenSet perfect for almost any vessel
The MAN L23/30H Mk3 GenSet has a 15-20% increased power output per cylinder unit

More power – same reliability

The MAN L23/30H GenSet has been trusted by owners and operators for stable, reliable and cost-efficient operation for more than five decades. With over 12,000 MAN L23/30H GenSets in active service, the L23/30H has proven to be one of the most reliable marine GenSets in the market and has a well-earned reputation for easy maintenance and longest time between overhauls (TBOs) in its class.

The new MAN L23/30H Mk3 GenSet improves on this trusted design in virtually every way. The engine has an exceptionally broad power range that can also accommodate SOx scrubber solutions and is designed to operate on Low Sulphur Fuel Oils in accordance with the IMO 2020 Sulphur Cap regulations.

This results in a cost-effective GenSet platform for years to come with easy access to spare parts and lifetime support.


The Mk3 version of the MAN L23/30H GenSets

Key features


  • Wide power range of 500kW to 1,800kW
  • IMO 2020 Sulphur Cap compliant
  • One less cylinder required than with the Mk2 version
  • 24,000 hours Time Between Overhaul (TBO)
  • 15-20% increase in power output/cylinder unit
  • Reduced fuel oil consumption
  • Connecting rod applying marine head design
  • Bedplate design for easy installation
  • Applying the popular SaCosone safety and control system


IMO’s global 2020 Sulphur Cap means that vessels will either have to use marine fuel oils with maximum 0.5% or 0.1% sulphur, or invest in SOx-reducing technology that will require higher auxiliary engine power. The new MAN L23/30H Mk3 GenSet supports both solutions.

For shipowners preferring to comply with the 2020 Sulphur Cap by operating on Low Sulphur Fuel Oils, the new MAN L23/30H Mk3 GenSet is a perfect choice. The engine is designed with coated fuel oil pumps to account for the poorer lubricating properties of Low Sulphur Fuel Oils.

Engine room layout

When running on Low Sulphur Fuel Oils, an additional advantage of the MAN L23/30H Mk3 GenSet is the increased power output. In many cases, the engine can be selected with one cylinder less compared to Mk1 and Mk2. This means lower engine weight and shorter length.

Thanks to the higher power output, the MAN L23/30H Mk3 GenSet is also especially suitable for installation in engine rooms designed with a SOx scrubber. 

The engine room for a MAN L23/30H
Mk3 GenSet can be designed with the same cylinder numbers as for a pre-2020 vessel without a SOx scrubber. This means that only a few changes are necessary in the engine room.

Service solutions for optimum cost-efficiency

MAN PrimeServ offers a worldwide service network with dedicated and experienced experts. Look forward to advanced modernization solutions for optimizing the reliability, availability, and economic efficiency of existing equipment. Furthermore, MAN's retrofit solutions and PrimeServ Assist digital services are tailor-made to customers’ specific applications and machinery.

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The MAN L23/30H Mk3 GenSet has the longest Time Between Overhaul in its class
The MAN L23/30H Mk3 GenSet is fully compliant with IMO 2020 Sulphur Cap regulations

A lifetime of support

With the new MAN L23/30H Mk3 GenSet, you get unique full lifetime support from specialized departments at MAN Energy Solutions. 

This starts in the planning phase, even before the order is placed, continues throughout the building phase at the licensee and shipyard, and extends across its operational lifetime even after the warranty ends.

WhoPromotion  & Sales
Engineering Engines
Production EngineeringOperationMAN PrimeServ
WhatUnique new building
technical and commercial promotion
Unique quality assurance
support at licencee and shipyard
Unique operation support at initial service stage and warranty follow-up

Worldwide network for unique technical service, support and spare parts sale

PrimeServ Assist: remote monitoring and data analysis with instant notifications

WhenPrior to new build orderProduction & Erection periodWarranty periodPost warranty period

Explore our interactive marine propulsion systems

Click here to access our Interactive Product Experience and see how MAN marine products enable a ship to operate on sea efficiently and reliably. Each of the products shown have their own key features displayed in 3D and explained. Explore our two-stroke main engine, GenSets, turbocharger, CP propeller and control system and our innovative digital offering “PrimeServ Assist”.
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Contact our experts

The new MAN L23/30H Mk3 GenSet is built to support your power needs today and for the future. 

Contact us now to explore your options.
Contact us

Past MAN ExpertTalks

Uptime anytime – the new L23/30H Mk. 3 and L21/31 Mk. 2 GenSets

(W. Europe Standard Time)
MAN ExpertTalk

In this session we will present the new state-of-the-art L23/30H Mk. 3 and L21/31 Mk. 2 auxiliary engines on which we apply innovative technology in combination with classic design principles.

Learn more about the application, benefits and proven GenSet expertise in this area.

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