Ferry propulsion systems, ferry engines, and more

A short answer is difficult to give because the best solution depends on the operational environment. Even for two ferries identical in size, one may operate a 1-hour route while the other may have a 31-hour route.

The most typical setup for ferry propulsion consists of mechanical machinery – engines, gearboxes, and CPPs – complemented by hybrid systems. Diesel-electric (DE) or gas-electric configurations work for certain types of ferry operations.

A typical set-up for high-speed ferries consists of four engines connected to four gearboxes and four waterjets.

Common to all configurations: if the distance is short, a fully battery-powered solution makes a lot of sense. 

There are many ways to reduce emissions and comply with new regulations. The following are only a few examples. There are many more that can be evaluated case by case.

• Modern engines: A new Wärtsilä engine is significantly more efficient than older models.
• Natural gas engines: For example, the methane slip in Wärtsilä’s latest engines is much lower than before. We are already well below the 3.1% limit set by FuelEU Maritime as the default methane slip level for four-stroke medium-speed engines.
• Energy-saving technologies: There are several solutions that can improve propulsion efficiency, such as EnergoProfin, GATE RUDDERTM, EnergoFlow, EnergoPac, and others.
• Ferry electrification: Options include modern shaft generator systems and shore power connections.
• Future fuel readiness: Wärtsilä engines are designed for fuel flexibility, and their modular structure makes them ready for fuel conversions. This helps ensure long-term compliance with regulations. 

Electric-hybrid propulsion can benefit ferries whose operational profile is suitable.

An electric-hybrid solution makes it easier to maintain optimal load, and this helps reduce greenhouse gas emissions. Such a solution usually includes more than one engine, and it is possible to start them only when needed. This also improves efficiency and saves fuel.

An electric-hybrid solution can be readier for future changes. This is because it would then be easier to replace an engine with new technology or with batteries, compared to replacing a solution that consists of two mechanically driven main engines.

However, some operational environments are such that the best propulsion solution will consist of mechanically driven main engines combined with state-of-the-art hybrid systems. Even for newbuild ferry projects.

Yes, Wärtsilä can retrofit older engines to make them compatible with new fuels. This, of course, depends on the engine type and its age – whether it’s 20, 10, or 5 years old. These details can be assessed together with the customer to find the best solution. 

Wärtsilä sees an increasing interest from customers in lifecycle service support. We can offer tailored service agreements according to customer needs. A service agreement with Wärtsilä will help

• reduce downtime – and especially unscheduled downtime
• improve fuel efficiency
• decrease emissions.

In short, a service agreement helps minimise operational risks.

Wärtsilä has a strong position as a leading ferry engine manufacturer and has held this position for a long time. When looking at the ferry orders placed in 2025, Wärtsilä holds a leading market share in medium- to large-size ferries.

The small ferries market is more fragmented, with no clear market leaders.