ZF launches new ENC marine transmission for all-electric vessels

The new ENC series is ZF’s first marine transmission that was developed explicitly for use in purely electrically powered vessels. [Photo: ZF]

With a growing number of fully-electric vessels either on the water, building, or at the planning stage , Friedrichshafen, Germany-headquartered transmission specialist ZF has responded with its new ENC marine transmission series. Developed explicitly for use in purely electrically powered ships, it is designed to deliver optimized efficiency with electric motors with a lightweight design and excellent NVH (noise, vibrations, harshness behavior. ZF says that the solution improves the electric vessel’s range and onboard comfort on board and ongoing operating costs, supports shipyards and operators in the transformation to greater sustainability.

According to forecasts, says ZF, the global market for electrically powered ships is expected to grow to $17.20 billion by 2032. By comparison, it was just $4.33 billion in 2024. This proves that electromobility in shipping is not a short-term trend, but – in more than one sense – a sustainable development on global waters.

Near the coast or on shorter routes, there is growing interest in pure battery-electric drives. These are an attractive alternative to conventional or hybrid units wherever shoreside charging infrastructure can be set up comparatively easily.

“With our new ENC marine transmission series, we now have an optimal solution in our portfolio for these applications to support the industry in its sustainable transformation,” says Wolfram Frei, sales manager commercial and fast ships at ZF

Experience from past projects was incorporated into the development of the new ENC series In Portugal, ZF had already equipped passenger ferries with electric drive solutions a few years ago to cross the Tagus River with zero local emissions. At that time, it was a conventional transmission that was tailored to this requirement.

“After this successful project, our motivation was to further optimize the efficiency of battery-electric drives. This paved the way for the development of the new ENC series,” says Frei.

No clutch, optimized efficiency

The ENC series was designed in such a way that the drive power of the electric motor is optimally transferred to the propeller even at high speeds and high ratios – a common scenario in electric shipping. This improved efficiency reduces energy consumption, delivering a greater range and better economy.

Unlike conventional and hybrid transmissions, this transmission series dispenses with a hydraulically actuated multidisk clutch (ENC = electric non-clutchable). As a result, the oil supply quantity can be significantly reduced, since a ‘peak consumer’ is also eliminated by omitting the clutch. In addition, the system oil pressure can also be lowered. Both factors ultimately result in a smaller oil pump and also increase mechanical efficiency. Depending on the customer’s requirements, the oil volume is supplied either via an electrically operated pump or a bidirectional mechanical pump.

ZF also lowered the oil level. “This reduces churning losses, which increases efficiency,” says Frei. Thanks to the smaller pump, the lower oil level and further structural optimizations, the ENC transmission weighs considerably less – up to 10% compared to similar solutions, depending on the version. Another development focus was on the acoustic properties to meet the special requirements of electric motors. The ENC therefore has outstanding NVH behavior.

The ENC series can be combined with all maritime ZF drive solutions, from the ZF 2000 to the ZF 9000. It thus covers a power range from 650 kW to 3,900 kW. It is suitable for all installation configurations (A/V, U, Z), center distances, attachments, transmission ranges as well as for fixed propellers, variable pitch propellers and waterjet drives.

“This provides shipbuilders with optimum flexibility in the design of the vehicles,” explains Frei. “The ENC is therefore ideally suited to electrify the operation of commercial vessels such as ferries, tugs, supply boats or river cruise ships on short routes.”

ZF can make use of proven standard components as well as the existing, worldwide service network of ZF Aftermarket in the production of the ENC. This ensures the supply of spare parts.

The new product is already attracting specific customer interest.

“We have inquiries from Portugal, Scandinavia, the USA,” says Frei. And concluderes: “This proves that sustainable ZF driveline solutions, as well as electromobility, are a global issue.”

The ENC marine transmission is part of a wide range of ZF solutions covering e-mobility across the transportation spectrum.