Jan De Nul’s latest Ultra-Low Emission Vessel, the trailing suction hopper dredger ''Diogo Cao'', was launched last month at the Keppel Nantong Shipyard in China.

Diogo Cao keeps NOx emissions to some 30% below IMO Tier III requirements and complies with forthcoming EU Stage V regulations for inland waterway vessels

The ‘green’ vessel is the second of three 3,500 m3 capacity hoppers to be launched, equipped with an exhaust gas treatment system filtering out and virtually eliminating many pollutants from the exhaust gases. In addition to the three 3,500 m3 hoppers, there will also be two of 6,000 m3 capacity and one of 18,000 m3 capacity. Five of the six vessels are being built at Keppel.

All six vessels will be diesel-electric powered, with engines allowing optimal use of generated power but with low fuel consumption and emissions. The vessels are equipped with a two-stage highly efficient exhaust gas filter system, resulting in emissions complying with the stricter European Stage V regulations for inland waterway vessels, which are due for implementation in 2020.

“We are delighted to be leading the way in compliance with the most stringent global emission limits with the world’s first EU Stage V dredgers, which will be highly fuel efficient, reliable, versatile and productive, said Jan De Nul’s new build director Robby De Backer. “Their use will enable dredging projects to be completed with the lowest level of emissions to date.”

“As the new dredgers will frequently operate in estuaries, rivers and coastal areas near urban areas, we decided to limit NOx emissions to a level 30% below the actual IMO Tier III requirements and to reduce other potentially harmful contaminants that are currently not regulated by IMO.”

The new vessels will operate with normally available ultra-low sulphur gasoil, with the exhaust gas treated in two stages by means of a Selective Catalytic Reduction (SCR) system and a Diesel Particulate Filter (DPF). The SCR lowers NOx to achieve EU Stage V levels for inland waterways. The second stage DPF removes particulates from the exhaust, also down to the future EU Stage V levels. Eliminating black carbon emission with the DPF significantly reduces the climate impact of these vessels.

The Diogo Cao measures 89.3m LOA with a beam of 22m. It will be capable of dredging to depths of 27.6m through an 800mm diameter suction pipe. Twin 1,100 kW engines will enable a speed of 11.3 knots.