Why propulsion efficiency is the name of the game

Why propulsion efficiency is the name of the game!

By focusing on optimising the lifecycle efficiency of ships, Wärtsilä's role as a full-service provider and one-stop supplier helps ship owners and operators reduce fuel consumption and emissions levels. And there's more.

By focusing on optimising the lifecycle efficiency of ships, Wärtsilä's role as a full-service provider and one-stop supplier helps ship owners and operators reduce fuel consumption and emissions levels. And there's more.

This is a direct response to global trends like high fuel prices and increased environmental awareness. Since 2013, new mandatory IMO regulations, known as the Energy Efficiency Design Index (EEDI), stipulate the mandatory collection of fuel consumption data on ships over 5,000 gross tons, something Wärtsilä is already well equipped to do with a portfolio of new product launches and recent acquisitions that provide continued benefits for vessel owners and operators.

The main components affecting a vessel’s propulsion efficiency are the hull, engine and propeller. By carefully analysing the interaction between these components, Wärtsilä has developed a portfolio of products and services that substantially increase operational efficiencies and cut costs for ship-owners and operators. The portfolio includes vessel performance monitoring and advisory services and energy saving devices, among other solutions.

“In order to maximise propulsive efficiency, a perfect marriage between propeller and engine is needed,” says Tamara de Gruyter, Wärtsilä’s Vice President Propulsion System Services and Area North Europe.

“Efficiency gains can still be culled from this age-old interaction, whether it be on new-builds or retrofits.”

De Gruyter has been working with propulsion systems since 1996 and has lead Wärtsilä factories and joint ventures in the Netherlands, China and Singapore. Her ambition is to develop innovative propulsion systems and fuel saving opportunities for all customers.

“But it is not a one-size-fits-all situation.” 

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Tamara de Gruyter, Wärtsilä’s Vice President  Propulsion System Services and Area North Europe.


Maximising output

“In modern ships, only 25 to 35 percent of the energy contained in the fuel is effectively used to propel the ship. The challenge is to reduce the loss factors involved in converting the main engine’s output into propeller thrust and thereby increase overall propulsion efficiency. An investment in reliable, modern propulsion technology has a short payback time and increases the fleet’s competitiveness,” says de Gruyter.

Over the years, and due to continuous improvement efforts, propeller efficiency has reached its physical limits considering the applicable design constraints. To further optimise the overall propulsive efficiency of ships, the industry has moved towards the development of energy-saving devices. These are devices that can be mounted onto or close to the propeller that help reduce the magnitude of axial, frictional, and rotational loss factors.

Energy saving devices also minimise emissions and can reduce underwater radiated noise levels. Impact of emissions and noise impact on sea life is also gaining in importance from an ecological and environmental perspective, something that de Gruyter has also championed. In 2014, the IMO officially recognised that underwater noise from shipping should be mitigated.

“Wärtsilä has deep cavitation and vibration analytics know-how which includes executing proper design, optimisation, maintenance, and navigation routines,” says de Gruyter.

“The economic arguments obviously exist. Furthermore, front-runners like the Port of Vancouver are offering discounts on harbour dues for visiting ships which have been fitted with measures that reduce underwater-radiated noise levels.”


Master of all

Wärtsilä has developed a wide range of products and services that address these environmental and efficiency requirements. The portfolio includes the Wärtsilä EnergoFlow, the Wärtsilä High Performance Nozzle, the Wärtsilä EnergoProFin and the new Eniram Skylight fleet performance monitoring and analytics service, among other solutions. 

Wärtsilä recommends monitoring and analysing the true condition of a vessel throughout its lifecycle to ensure optimal performance. In practice, this includes keeping the equipment fine-tuned and the hull clean (with smart coatings and well-chosen cleaning intervals), as well as looking into other efficiency improvement opportunities.

According to de Gruyter, Wärtsilä’s plan is to maintain and continuously improve its role as a full-service, one-stop supplier of efficiency analysis tools and improvements.

For example, in December 2017, Wärtsilä announced the acquisition of underwater ship maintenance company Trident B.V., a Netherlands-based specialist in underwater services.

“This acquisition supports Wärtsilä’s strategy on several fronts, starting with our ambition to enable sustainable societies with smart technology. Reduced fuel consumption, efficiency improvements and higher utilisation rates are always on the top of the operators’ agenda,” says de Gruyter. “At the same time, environmental issues are becoming an integral part of customers’ business planning. Trident is a pioneer in the development of environmentally sound solutions for hull cleaning, for example. Our goal is to take away customer worries by selling efficiency as a service.” 

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Wärtsilä EnergoFlow improves fuel efficiency by up to 10%.


Efficient choices

Wärtsilä EnergoFlow

Wärtsilä’s EnergoFlow is an innovative and cost-effective pre-swirl stator that increases fuel efficiency by up to 10 percent. It improves the propeller inflow by guiding one side of the stern flow in the opposite direction to the propeller’s direction of rotation and generates pre-swirl.
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The Wärtsilä Nozzle

The Wärtsilä High Performance (HP) Nozzle increases propeller thrust and efficiency by up to 15 percent by reducing the propeller load and generating forward thrust. This nozzle can be used on a broad range of heavy duty vessels such as tugs, anchor handling vessels, dredgers and trawlers.
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Wärtsilä EnergoProFin

This is an energy saving propeller cap with fins that rotate together with the propeller and provides an average fuel saving of two percent, with a payback time of less than one year. It works by weakening the hub vortex, and is available on new-builds as well as existing vessels, and is applied already on over 250 installations worldwide.
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Eniram SkyLight

By remotely monitoring the propulsion system and analysing performance data, service experts can detect any variations in propulsion efficiency and take measures to correct the situation by, for instance, replacing a worn part or recommending a propeller damage check.

In late 2016, Wärtsilä acquired Finnish marine technology start-up Eniram, and has since developed the SkyLight, a fleet performance monitoring service highlighting fuel and speed performance data, that is currently installed on over 270 vessels.
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Written by
Alexander Farnsworth