News - Week 36, 2004
The 'Lexington' - cutter suction dredger for Cottrell Contracting Corporation, USA Cottrell Contracting Corporation, a dredging contractor based in the USA, will add a new medium-sized cutter suction dredger to its fleet by the end of the summer, 2004. Named Lexington, this 18 CSD has been designed by VOSTA LMG. A component package with a spud carrier and cutter system, including ladder, has also been delivered by VOSTA LMG. Local project management will be handled via the US office, VOSTA Inc. The dredger is being built, in co-operation with Cottrell Contracting Corporation, at the Tidewater Skanska Inc shipyard, USA. The 18 CSD is the US equivalent of a CSD500, but will have accommodation for 25 people onboard and will be built to work in a variety of conditions. The current Cottrell Contracting fleet needed to be extended due to an increase in workload in the United States.
The contract for VOSTA LMG includes the engineering of the dredger and the supply of major components such as dredge pump diesels and gearbox, generators, spud carrier, spuds and spud hoisting system, winches and a cutter ladder, including a SC10 cutterhead. The dredger will perform maintenance dredging in the USA on Cottrell Contracting Corporation projects. The ship was designed in close cooperation with the owners, who are also supervising the building at the local yard, together with a senior engineer from VOSTA Inc., a wholly owned subsidiary of VOSTA LMG. The dredger can work at a maximum depth of 18 m (60 ft). Its length (over all) is 61 m (200 ft), with a breadth of 12 m (38 ft) and a draught of 1.6 m (5.2 ft). The dredger can also work in wide cuts, using its long and heavy anchor booms, 200 kN hydraulically driven side wire winches and its hydraulically driven spud carriage with 25 m (83 ft) long spuds. The cutter unit, with a maximum available cutter power of 223 kW (300 hp), has been designed and supplied by VOSTA LMG to work in sand, clay and cemented soils suitable for 300 hp. The cutting performance can be optimized at dredging depths of between 6 and 18 m below the waterline, using the variable cutting power. The dredger has a 450 mm (18) diameter suction pipe. The 1194 kW (1600 hp) Fairbanks Morse driven inboard dredge pump can be assisted by a submersible, electrically driven, 600 kW (800 hp) dredge pump on the cutter ladder. The combination of both pumps makes the dredger capable of long distance pumping and dredging, up to 60 ft. For safety reasons, the pump room has been separated from the engine room by a watertight bulkhead. The optimum layout and use of watertight doors combines an easily accessible engine room with high stability and safety.
Two 910 kW generator sets will be installed to supply the board net, hydraulic power packs and ladder pump. The generator system has been designed to run separately and in parallel. In order to keep the electrical and instrumentation power net clean, the power supply systems will be equipped with the appropriate filters and drive systems. The ladder pump is direct electric driven by e-motor and variable frequency drive. The "Lexington" accommodation includes an office, a kitchen/mess room and sanitary facilities. In order to minimize noise levels, the accommodation will be furnished with anti-vibration shocks and is, as much as physically possible, disconnected from the engine room. On top of this, a spacious operating cabin ensures maximum view of the deck and working environment. A U-shaped control desk with conveniently arranged controls and instrumentation will provide an efficient working environment. For maximum dredging efficiency, state-of-the-art instrumentation and controls are to be installed, such as a dredge profile computer and positioning system. A VOSTA LMG automation system, including velocity and density management, and system and dredging monitoring powered by Dredgepack- will be installed.
After the commissioning, trials and hand over ceremony, the new CSD will start her first project for Cottrell Contracting Company. The Lexington will be used to complete a $4.7 million beach nourishment project for the Philadelphia District, United States Army Corps of Engineers. Approximately 200,000 cubic yards of sand will be dredged from an offshore borrow area and pumped on a badly eroded adjacent beachfront. Work is scheduled to begin, approximately, October 1, 2004. VOSTA LMGs office in the US, VOSTA Inc., played a vital role in managing the order. President Bernard Huelbert is happy that his office had the opportunity of supporting Cottrell Contracting Company in the building process. The Cottrell deal shows the need for a local VOSTA LMG presence in the US market, not only in securing orders, but also in supporting US customers at all stages of a project, with the specialized engineering and procurement help of colleagues in Europe. About Cottrell Contracting Company: Cottrell Contracting Corporation has been engaged in the hydraulic cutter suction dredging business since its founding in 1928. Over the years its areas of operation have grown from the Virginia - Maryland areas in the 30s and 40s to the entire eastern seaboard of the USA and Caribbean today. Cottrell Contracting serves a wide variety of customers from government agencies to private industry groups. Cottrell Contracting undertakes new work as well as maintenance dredging projects. Cottrell also specializes in habitat creation and environmental restoration projects.
Lexington - Main detail (PDF File)
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