C-Job Naval Architects has delivered a concept design to Switijnk Shipping for a wind-assisted general cargo vessel, known as a Flettner Freighter, that is expected to achieve fuel savings of approximately 13 percent.

The 8,500 dwt vessel will be equipped with two Norsepower rotor sails that will supplement the main engines.

As HLPFI reported here, Switijnk approached C-Job following the latter's involvement in the European Union SAIL project, for which C-Job originally developed the 4,500 dwt Flettner Freighter.
After studying the wind patterns on Switijnk's proposed sailing routes, C-Job modified the design of the new vessel, called the FF8500, to include two larger rotor sails, rather than four.

"Our experience from the Project SAIL study showed that rotor sails were the most viable choice compared to other wind-assisted propulsion systems," explained C-Job business manager Jelle Grijpstra. "And then, together with Finnish rotor sail supplier Norsepower, we concluded that two larger rotor sails were most effective for this project.

"This was because these would yield a comparable propulsive force to four smaller units."

The vessel will measure 129.65 m in length overall (LOA), and has been designed with a maximum draught of 8.5 m.

While the fuel source of the vessel's main engines has yet to be decided upon, C-Job has reserved space for LNG engines, although this will be dependent on LNG bunkering infrastructure along Switijnk's sailing routes.

With the concept design of the vessel complete, the next stages of the design process include a basic  design and a detail design as well as testing at the Maritime Research Institute Netherlands (MARIN).

The intention of this velocity prediction research is to validate the design and to quantify the fuel savings to be gained, said C-Job.

A spokesperson for C-Job said: "This new design is creating quite some attention and we hope this will benefit the chances of getting more financing for our client, Switijnk Shipping."

Once the financing is arranged, Switijnk will be able to select a shipyard to build the vessel.