Izar dredgers head for Asia

Two sister ships, ordered by Belgium dredger operator Jan de Nul, were launched earlier this year at Izar?s Sestao shipyard

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Named Filippo Brunelleschi and Francis Beaufort, the vessels are trailing suction hopper dredgers, each with an 11,300m3 hopper capacity suitable for various operations

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These include dredging by the trailing suction pipe, delivering the spoil either ashore, into the hopper or directly overboard in the case of light dredged spoil

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Spoil is dumped on the seabed through a row of hinged doors on the bottom of the ship or by two shallow-water dumping doors

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A bow connection arrangement is suitable for coupling to a flexible floating pipeline, as well as a bow jetting installation

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The Sestao shipyard is set to deliver the Filippo Brunelleschi and Francis Beaufort in September and November respectively when they will operate in southeast Asia on reclamation projects

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These new buildings, as well as the previous Izar built 16,500m3 dredgers Juan Sebasti?n de Elcano and Kaishuu, will be operated by Jan de Nul and, while the new ones are smaller than their predecessors, they will be more manageable, yet able to dredge down to 71m using a 3,400kW underwater pump

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Two medium speed 12V32/40 MAN B&W diesels each with a 5,760kW output at 750 rev/min power two Wärtsilä CP propellers via flexible couplings and Jahnel Kestermann reduction gearboxes to give a service speed of 15 knots

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An auxiliary genset ? Caterpillar engine with 1,550kW output at 1,800 rev/min ? drives an alternator rated at 1,050kVA, 440V, 60Hz, and an emergency genset

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Out of the total main and auxiliary output of 12,790kW, some 7,500kW will be available for the pumps in the trailing and pumping ashore mode

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The main engines also power the two 6,750kVA shaft generators, which feed the bow and stern thrusters, jet pumps and the onboard electricity network

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Dredging equipment

Two pumps made by IHC comprise the dredge pumping set

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A shore discharge dredge pump double walled type is driven by an electric motor via gearbox, with a maximum power of 7,500kW

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The submerged dredge pump single walled type is driven by a 3,400kW electric motor

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The dredgers each have a 1200mm internal diameter suction pipe, dimensioned for dredging at a depth of 32

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5m and adjustable to 52 and 71m

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A drag head with a 1,200mm bore, with adjustable visor and swell compensator, is fitted to the end of the suction arm

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This compensator lets the drag head move 6m in relation to the forward movement of the vessel

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The suction pipe is hoisted by three gantries at the drag head, the intermediate cardan joint and the trunnion connection of the arm to the hull

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Each gantry is provided with a hydraulically driven winch

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The hopper form is designed for optimal settlement and discharge of the spoil through the bottom doors and the bow

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The two doors on the bottom of the hopper are for unloading the dredged material when there is not enough depth to unload through the ship-bottom doors

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To speed up the unloading of dredged material, a piping system fitted with nozzles sprays pressurised water from different positions in the hopper

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Two TTS/Izar Manises electro-hydraulic cranes are installed for repair and replacement of the dragheads and other elements that form part of the suction line, as well as repair work in general

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One crane has a 45t hoisting capacity and a maximum reach of 16m

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The other has a 14t hoisting capacity at a maximum reach of 22m

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Sophisticated

automation

Dutch company Imtech supplied the Jan de Nul new buildings with its Unimacs control system that integrates navigation, propulsion, alarm, monitoring, control and communications

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As supplier to many navies worldwide, the installation of Imtech?s system represents an important technological development in the dredging world

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It provides full integration of the navigation-DP/DT systems (including radar, ECDIS, AIS, VDR and auto-pilot functions), the alarm, monitoring and control system and the dredging control and

automation

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With redundancy features, the high-speed network has no single point of failure while multi-function touchscreen workstations improve efficiency and operation

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Hardware commonality in the system reduces the spare parts inventory and simplifies maintenance

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Izar: the dredger expert

With a long list of dredger new buildings to its credit, Izar?s yards at Sestao and Gijon have built an enviable reputation in the dredging industry for quality at a competitive price

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As well aso the two vessels mentioned here, Izar?s yard at Gijon is constructing two smaller dredgers for Jan de Nul

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Named Taccola and Francesco di Giorgia, these 4,400m3 trailing suction hoppers with a length of 95

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4m and a relatively wide beam of 21m are for shallow water

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Total installed power will be 6,050kW of which 3,000kW will be available for shore discharge

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Maximum dredging depth for the 900mm suction pipes will be 24

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3m

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Both will be delivered this year

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