MAN L21/21 Shipsets Power Construction, Commissioning Vessels for German Operator

MAN Energy Solutions will deliver four shipsets to the Wenchong shipyard in China, each comprised of three MAN 8L21/31 MK2 generator sets. These will be installed on four construction and commissioning service operation vessels (C-CSOVs) operated by German Offshore Shipping (DO). CMP, an official licensee, will manufacture the engines in China, and delivery is expected in Q1 2027. The order includes options for additional C-CSOVs.

“We are experiencing increased demand for efficient, competitive engine designs for the offshore wind segment, which our portfolio of small-bore propulsion engines is fulfilling, backed up by our MAN PrimeServ after-sales network,” said Hakon Juel Hansen, Manager Engine Promotion & Business Development, MAN Energy Solutions. “With these technically sophisticated offshore vessels, DO is showcasing the adaptability of our engine portfolio.”

These engines will be delivered in a diesel-electric propulsion configuration, with part-load optimization for enhance fuel efficiency. The diesel-electric concept aligns with the dynamic positioning stage 2 system set by Det Norske Veritas, which outlines back-up systems, components, and redundancy options to prevent loss during faults.

C-CSOV rendering; image credit: MAN Energy Solutions

“These 12 engines represent a significant contract, amounting to over 20 MW of power,” said Colin Peesel, Head of Sales & Promotion, MAN Energy Solutions, Germany. “The L21/31’s many advantages include its class-high fuel efficiency and low noise-and-vibration levels. Crucially, it is future-proofed regarding operating fuel. Besides MGO, it can run on biofuels such as HVO and FAME, and it is additionally delivered methanol-ready.”

The 96-meter C-CSOVs execute support services during the commissioning and operation of offshore wind farms, but DO’s concept incorporates higher flexibility and adaptability for the construction and cable-grid sectors. The design itself enables the L21/31 engine to be retrofitted for future methanol combustion. Norway’s Naval Architects Salt Ship Design AS created the basic, decarbonization-focused design for these C-CSOVs.

“MAN Energy Solutions’ L21/31 is a cornerstone in our endeavor to develop a vessel with a minimal environmental footprint,” said Johannes Wolters, Managing Director of Deutsche Offshore. “The engines offer us benchmark performance in the here and now, while granting us seamless readiness for our decarbonization strategy.”

MAN’s Marine News

In mid-April 2025, MAN Energy Solutions agreed to deliver 10 marine propulsion packages to Hindustan Shipyard (HSL) in Visakhapatnam, India, which will build five fleet support ships (FSS) for the Indian Navy. The FSS large-scale replenishment vessels are intended to improve and expand the Indian Navy’s operational capabilities. With these propulsion packages, HSL fulfills its plan to enhance the Indian Navy with power generation technologies and international partnerships. The entire order features:

• 10 x 20-cylinder 32/44CR engines
• Main reduction gearboxes
• Shaft generators
• Bow thrusters
• MAN Alpha Navy controllable pitch (CP) propeller systems

The 12 MW, 20-cylinder 32/44CR models are the largest four-stroke engines supplied to the Indian Navy in 50 years and is used in numerous FSS’s across navies worldwide. The medium-speed marine diesel engines are each supported by two Indian-made, 1-Mwe shaft generators, with each vessel propelled by a naval Alpha CP propeller. The company enhanced the hydrodynamic propeller design with balanced efficiency and reduced noise and cavitation, improving overall performance across operating conditions. MAN Energy Solutions India will handle installation and commissioning services.