The machinery arrangement driving Project Forward’s gas-fuelled bulk carrier design has been awarded a patent in South Korea. Project Forward is a collaboration led by Greek shipmanagement company Arista Shipping to develop and build some of the first gas-fuelled bulk carriers. Partners include Wärtsilä, ABS, Deltamarin and GTT.
The patent features two medium-speed, gas-fuelled engines coupled to a single shaft by power take-out generators linked directly to the engines, rather than through the gearbox. The arrangement means that the main engines can also be used for electricity generation at port without turning the propeller.
The main engines are used to generate propulsive power and electricity at the same time, with no auxiliary engines are required. This results in a doubling of propulsive redundancy and a quadrupling of electrical generation redundancy while ensuring safe return to port, according to the project leads.
Arista Shipping technical director and Project Forward chief technology officer Antonis Trakakis told Marine Propulsion that the innovative arrangement bridges the gap in thermal efficiency between two-stroke and four-stroke engines. “When running on LNG, even with four-stroke engines, we have the same total fuel consumption as installations incorporating two-stroke engines,” he said.
The arrangement also improves aft streamlining compared to conventional bulk carriers, while the positioning of the engines above gearbox centreline allows for further optimisation of hull lines.
Mr Trakakis said that the South Korean patent represented recognition of the concept from an important shipbuilding country. He noted that Korea’s yards had been very close to the concept development so far, although “very far in price”.
Project Forward signed a letter of intent in April 2018 to build 20 of the 84,000 dwt bulk carriers at Jiangsu Yangzijiang Shipbuilding. Mr Trakakis said that the search for a building contract has now moved on and the project has started discussions Oshima Shipbuilding. But he admitted that shipyards were proving reluctant to consider such projects, “mainly because they are not convinced about the future of LNG as fuel and the higher costs involved".
Project Forward has selected Wärtsilä 31 dual-fuel engines to power the ships.