From Road to Sea: Why Element is the ideal epicyclic gearbox for marine applications

As the global maritime industry moves toward cleaner, more efficient propulsion systems, an increasing number of naval architects and shipbuilders are exploring electrification as a pathway to decarbonisation. Particularly those working with smaller vessels under 400 gross tonnage (GT).

But for many, the transition to electric drive presents a unique set of challenges: tight development schedules, limited engineering resources, and constraints around packaging, performance, and cost.

“One of the most critical early decisions in electrified powertrain development is selecting the right Electric Drive Unit (EDU),” explains Peter Trueman, Market Head for Marine, “Whilst electric motors are relatively easy to scale and customise, choosing the right epicyclic transmission to match often requires a trade-off between adding significant cost to develop a clean sheet solution, or to compromise on packaging or performance.”

The Element modular transmission range seeks to overcome this challenge with a collection of three pre-engineered baseline reduction drives which are customisable with a range of gear ratios to match operational requirements.

Available to in low, medium, and high torque variants and compatible with a range of motors, these units are designed to enable rapid prototyping of EDUs with low engineering effort.

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Compact packaging for space constrained applications

Whilst originally developed with high-performance automotive applications in mind, the Element range has quickly demonstrated its versatility across a wider spectrum of industries. This is especially true for smaller marine craft where space, efficiency, and reliability are paramount.

“One of the real strengths of the Element platform is its compact size and low weight,” adds Peter. “This alignment of the motor and gearbox along a single axis is especially beneficial for marine vessels where space is at a premium.”

The transmission’s slim, cylindrical profile allows it to be mounted closer to the stern tube, freeing up valuable hull volume and creating more usable internal space. An increasingly important design consideration for both commercial and recreational watercraft.

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Quiet operation

Beyond packaging advantages, Element’s marine suitability is also reinforced by its exceptional NVH (noise, vibration, and harshness) characteristics, an area in which Ricardo has invested heavily. This is especially important because as electric motors replace traditional ICE engines, engineers can no longer rely on engine noise to mask noise associated with transmission operation.

“Certain applications in the marine sector require designers to be very conscious of system noise. For these segments, the demand for ultra-low NVH is non-negotiable” explains Peter, “Decades of precision manufacturing experience for our top-tier motorsport and performance automotive clients mean that we can fine-tune the gear microgeometry and contact ratios to suppress vibration and noise even at high RPM.”

Matching performance with precision for ease of propulsion system conversion

“We’ve designed the interface to accept a standard spigot diameter and a generic mounting arrangement,” adds Peter, “This can accommodate a cooling collar between the motor and gearbox, making it straightforward to implement a shared cooling system. This is especially useful in enclosed engine rooms or pod-based propulsion setups.”

Element’s wide range of reduction ratios also offers marine designers significant flexibility in matching high-speed electric motors with propellers optimised for different load profiles and mission requirements. This is particularly advantageous for operators seeking to replace legacy ICE systems with electric drivetrains, where shaft speed and torque conversion must be carefully controlled.

And crucially for mission-critical marine applications, the Element units are engineered for durability, designed to endure harsh operational conditions without failure. “We’re not just building for performance, we’re building for reliability,” notes Peter.

“That’s especially important in applications where gearbox failure is simply not an option.”

Marine Propulsion System designers! It’s time to Find your Element

Although Ricardo is most widely known for its automotive expertise, our cross-sector experience also positions us perfectly to support marine, off-highway, and defence applications.

“With the ramp up on decarbonisation policy targeting vessels below 400GT, we are seeing more and more clients considering an electrified solution for their product portfolios – from battery electric and hybrid through to alternative fuels and even hydrogen fuel cell,” adds Peter, “Whatever decarbonised propulsion system solution that marine OEMs opt for, Ricardo recognise that there is increased pressure from the market and from regulators to develop new products quickly and cost effectively.

“Ultimately, Element is designed to make the transition to electrification easy for our clients. It gives vessel designers and OEMs a plug-and-play solution that lets them adopt electric propulsion without starting from scratch. It's modular, efficient, and ready to meet the rigorous demands of the marine environment.”

Whether you’re retrofitting a legacy platform or building a new electric vessel from the ground up, Ricardo’s Element range offers a ready-made, adaptable gearbox for marine applications. With a flexible suite of ratios, scalable torque capacities, and exceptional NVH performance, Element helps shipbuilders and integrators accelerate development without compromising on quality or performance.

If you're working on vessels under 400GT and need a trusted partner to support your electrification journey, speak to us today about your marine application. Our team can help you select the right Element unit for your needs, or work with you on developing a bespoke solution tailored to your vessel's mission profile.

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