Construcciones Navales del Norte (La Naval de Sestao) of Spain’s Basque country delivered the “Simon Stevin” to Jan de Nul in February. Driven by a diesel-electric propulsion system comprising a series of MAN Diesel 32/40 engines, the new addition to the Belgian group’s fleet is the world’s largest fall-pipe and rock-dumping vessel with a capacity of 19,500 m3.

Construction of the ship lasted 26 months, with keel-laying taking place in April 2008 and launching in March 2009. The Simon Stevin recently departed for Australia for its first commercial projects.

The MAN Diesel 32/40 engine
The Simon Stevin is powered by five MAN Diesel nine-cylinder 32/40 main engines. Each delivers 4,500 kW at 720 rpm and is manufactured by STX Engine Co., Ltd., MAN Diesel’s Korean licensee. The five engines comprise a diesel-electric power plant that generates enough electricity to power a city of 130,000 people, according to the ship owner.

The Simon Stevin
The Simon Stevin will mostly be deployed in offshore applications, such as the laying of oil and gas pipes at great depths; the vessel can level the seabed and dump rocks down to a depth of 2,000 m. According to Jan de Nul, the fall pipe can process rocks with a diameter up to 400 mm, a figure greater than any other fall-pipe vessel in service.

The fall pipe has an advanced, fully automatic unfolding system, featuring an ROV (Remotely Operated Vehicle) at its bottom that accurately corrects its position. The 191-metre-long vessel has a 33,500 tons loading capacity, some 25% greater than the previous record-holder, and is capable of dumping 2,000 tons of rock per hour. The Simon Stevin can accommodate more than 70 persons and has its own helipad.32/40 capabilities

32/40 capabilities
The four-stroke engines run on HFO and are capable of continuous operation at loads down to 20%; running at even lower loads is possible for limited periods, thanks to the engine’s optimised design. The 32/40 can also accept overloads of 10% in conditions characterised by frequency variation.

As the Simon Stevin is subject to a dynamic load demand, high and sharp load variations can also occur. Accordingly, each engine is fitted with a so-called “jet assist” device that enables a quick response to such variations by injecting compressed air directly into the compressor wheels of the turbochargers.

MAN Diesel’s 32/40 type is characterised by an optimised, operational economy and minimal maintenance requirements. One of its stand-out characteristics is its low lube-oil consumption of approximately 0.5 – 0.8 g/kWh, a figure that was considered as a design parameter for the piston liners, covers and rings.

Another stand-out characteristic is the 32/40’s stepped piston. Here, the crown is forged with high-quality, stable steel (with shaker cooling), while the skirt is cast in spheroidal graphite cast iron. This kind of piston, together with a fire ring, prevents bore polishing of the cylinder liner and reduces lube-oil consumption. Furthermore, the chromium-ceramic composition of the first piston ring provides a resistance that contributes to long periods between maintenance.

As with all MAN Diesel engines, NOx emission levels for 32/40 engines fall below the upper limits specified by the IMO without negatively affecting fuel consumption or operation. The 32/40 type can also take advantage of SCR (selective catalytic reduction) technology to meet even more stringent NOx limits.

La Naval de Sestao
The La Naval de Sestao shipyard is currently finishing the construction of the dredger “Leiv Eriksson”, a sister ship to the record-breaking “Cristóbal Colón” and due for delivery in April this year. Ordered by Dredging and Maritime Management S.A., a Jan de Nul subsidiary, these twin vessels feature two MAN Diesel 16V48/60B main engines and are, by some distance, the largest trailing suction hopper dredgers in the world in terms of capacity. They can dredge up to a depth of 155 m, a technical feat that only Jan de Nul is currently capable of achieving.

These two dredgers, combined with the construction of the Simon Stevin, demonstrate La Naval de Sestao’s expertise in building complex and highly specialised ships, and show the confidence that cutting-edge, specialist marine segments have in MAN Diesel’s efficient and powerful engines.

Jan de Nul
The Belgian Jan De Nul Group provides global services within the construction and maintenance of maritime infrastructure and its ship-owning arm specialises in services for the offshore oil and gas industry. The construction of vessels at La Naval de Sestao is part of a construction programme running between 2007-2011 worth EURO 1.8 billion. The programme aims to create the largest and most modern dredging fleet in the world, capable of carrying out even the most demanding offshore dredging, rock dumping and construction works, in the process cementing the Jan de Nul Group’s position as a leader within international dredging and offshore niche markets.

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