Innovative LNG carrier machinery configuration granted patent by South Korea

Malcolm Latarche
Malcolm Latarche

07 January 2019

An innovative use of dual fuel engines and a new hull design developed by Athens-based Arista Shipping as part of its Project Forward initiative has been granted its first official patent right by South Korea.

The Project Forward initiative led by Athens-Based Arista Shipping, demonstrates that with LNG as fuel, an advanced hull design, and highly efficient propulsion machinery, it will be possible to meet the IMO’s target for a 40% reduction in carbon intensity by 2030. The patented machinery arrangement consists of two low-pressure, four-stroke Wärtsilä 31Dual Fuel main engines and two PTO/PTIs, coupled on one shaft that drives a CPP propeller.


Arista claims that this arrangement doubles the propulsion redundancy, quadruples the power-generating redundancy, and provides safe return to port, setting a new standard and lowering operating expenses. Th arrangement also allows for an improvement in the streamlining of the aft part, the percentage of which is not taken into account in the consumption tables. Further, the positioning of the engines above gearbox centreline allows for additional hull lines’ optimisation.

Model tests of the Project’s concept vessel indicate that the EEDI rating is well below the current most stringent Phase III level. EEDI Phase III is applicable to ships built after 2025 and signifies a 30% reduction from the 2008 reference level.

Last year the IMO announced ambitions for a possible further reduction in CO2 emissions per transport work of up to 70% by 2050. One commonly discussed way to reduce such emissions has been to limit the propulsion engine power, but this would require a significantly lower service speed, resulting in a serious impact on the chain of logistics. Project Forward shows that this 70% reduction in CO2 emissions target can be met, even without lowering service speeds, through the use of carbon neutral fuels mixed with LNG. Such carbon neutral fuels can be transported, stored, and consumed in a similar way to that of fossil LNG.

“Through the advanced engine technology available today, LNG has a clearly superior well-to-wake emissions profile compared to liquid fuel. LNG appears not as a transition fuel, but the fuel of tomorrow and for many years to come,” says Antonis Trakakis, Technical Director at Arista and Chief Technology Officer of Forward Ships.

The concept vessel’s hull form has been optimised in cooperation with Finnish ship designer Deltamarin and classification society ABS. “The efficient propulsion design concept for Project Forward is based on a novel arrangement featuring just two highly efficient Wärtsilä 31DF engines without auxiliary gensets. The project is totally in line with Wärtsilä’s Smart Marine vision that foresees an era of concept solutions delivering optimal efficiency, safety, and environmental sustainability,” says Johnny Kackur, General Manager, Wärtsilä Marine Solutions.

In addition to Arista Shipping, Deltamarin, ABS and Wärtsilä, the French LNG membrane containment system designer GTT is also involved in the project. The vessel is fitted with an LNG tank positioned midships.