Jan De Nul Group has ordered a 6,000-cubic-meter (7,847-cubic-yard) and an 18,000-cubic-meter (23,543-cubic-yard) trailing suction hopper dredge. Cosco (Dalian) Shipyard Co. Ltd. will build the larger vessel in its shipyard in Dalian in China, and Keppel Singmarine Pte. Ltd. will build the smaller trailing suction hopper dredges in Singapore.
Both hopper dredges are dual fuel, diesel-electric, with all main drives electrically driven via frequency converters and power generated by three diesel-driven generator sets. A-symmetric load sharing, ‘fuel-mapping,’ and engines that automatically start and stop depending on power demand combine to reduce fuel consumption and emissions. In addition, each vessel also has a selective catalytic reduction (SCR) system installed so the engines exceed International Maritime Organization (IMO) Tier II and Tier III requirements for reducing nitrogen-oxide (NOx) emissions. IMO requirements are similar to the U.S. Environmental Protection Agency’s Tier 4 requirements that emissions from non-road diesel engines reduce particulate matter and NOx by about ninety percent.
The 18,000-cubic-metervessel is equipped with a single suction pipe, with a submerged dredge pump. The hopper is subdivided in two parts, enabling sailing on even keel, at all loading conditions. Two double-walled shore-discharging pumps with a total power of 14,000 kW are installed. The dredge is 166 meters (544 feet) in length and can dredge to a maximum depth of 86 meters (282 feet). The 6,000-cubic-meter dredge is 111.7 meters (366.5 feet) long with a maximum dredging depth of 35 meters (115 feet).