The engine manufacturer MAN Engines has expanded its in-line six-cylinder platform with a new generation of engines. These are designed specifically for yachts and sport fishing boats.
The new 12.4-litre MAN i6X engine delivers an output of around 735 kW. It is largely based on the MAN D2676 technical platform, which was introduced in 2015 for workboats and (under the name MAN i6) for yachts. According to the manufacturer, the high-performance MAN i6X shares many common components with the existing MAN i6 series.
A newly developed turbocharging concept, which still requires only a single turbocharger, contributes significantly to the increase in power. This approach makes it possible to tap into new power ranges on a tried-and-tested basis whilst deliberately limiting the complexity – and thus also the weight – of the system, according to MAN Engines.
Single-stage turbocharging concept
The key feature of the MAN i6X is the newly developed turbocharging concept. The engine is designed to achieve high power output with a single-stage system. According to MAN Engines, this represents a unique approach in the selected power class, as comparable power levels are often achieved using multi-stage turbocharging systems. With the MAN i6X, however, the aim is to reduce complexity and specific weight whilst ensuring highly dynamic responsiveness.
According to the information provided, the engine’s design deliberately focuses on the interplay between power, dynamism and reduced specific fuel consumption compared with the previous model. A key focus is on the rapid availability of the maximum torque of 3,250 Nm and, consequently, on agile acceleration. For applications in the yachting and sport fishing sectors, this means that increased power and dynamism are not only delivered within the rated power range, but particularly in situations where an immediate response from the propulsion system is required, especially in the lower rev range – for example, when accelerating or manoeuvring.
The further development of the MAN i6X focuses on the functional areas relevant to the higher power range. These include an innovative turbocharging system and thermal management. An enhanced intercooler system and an expanded, demand-driven oil cooling concept ensure stable operating conditions even under high loads and enable sustained power output within defined operating profiles.
According to the manufacturer, the chosen design has a direct impact on the engine’s power-to-weight ratio, which stands at ~0.6 kW/kg with a displacement of 12.4 litres. “The MAN i6X thus sets a new benchmark in this class. For our customers, this means high performance from a compact, clearly structured engine platform,” says Reiner Rößner, Head of Sales at MAN Engines. For shipyards and system integrators, this provides additional flexibility in the design of yacht and sport fishing applications, particularly where performance, dynamics, weight and integration requirements are closely interlinked.
The new MAN i6X engine generation is designed for use in international markets and, according to MAN Engines, will comply with the relevant emission requirements: IMO Tier II, EPA Tier III and the EU Recreational Craft Directive 2013/53/EU. Furthermore, the MAN i6X has dimensions that are virtually identical to those of the MAN i6, whilst the customer interfaces remain the same. This means it can be integrated into existing vessel designs and used under a variety of regulatory frameworks.
Within this engine generation, the 735 kW power rating represents an extension of the existing range. In addition to the 735 kW version, a 662 kW variant will also be available. These complement the existing variants of the MAN i6 in-line six-cylinder engine – rated at 537, 588 and 625 kW – and open up applications that previously often had to be realised using alternatives with greater weight or larger installation space.
The MAN i6X will be unveiled for the first time at the Cannes Yachting Festival in September 2026. The engine will be available as standard from the first quarter of 2028.
