The Ham 318 trailing suction hopper dredger, owned by HAM Dredging, was sub contracted by IHC Holland to its subsidiary van der Giessen-de Noord in the Netherlands. It has an overall length of 17,615m and is 159m between perpendiculars. The dredger has a moulded breadth of 32m and registers 24,897gt. It has a 57,360t displacement, a 40,560t deadweight and a 13m draught. The vessel is stabilised by 3,163m³ of water ballast. There is also storage for 2,800m³ of heavy oil and 300m³ of diesel oil.
DREDGING EQUIPMENT
The main dredging equipment consists of two IHC Holland 12m diameter trailing suction tubes, each fitted with a submerged dredge pump, allowing dredging up to a depth of 55m and after lengthening of the tube, up to 70m. It will be possible in the future to extend the tube to facilitate dredging to depths of 110m. The twin submerged pumps are IHC Holland HRLD 193-48-110 units with an output of 2,500kW each. There are also two IHC Holland HRMD 262-56-130 inboard with an output of 2,750kW each. The HAM 318 has a hopper of 23,700m³.
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HOPPER
The hopper is equipped with one row of eight bottom doors for discharging the load. The load can also be discharged by means of a self-emptying suction system, in which installation the sand is pumped out over the bow through a floating pipeline, or discharged ashore through a ‘rainbow’. In all these cases, the unloading process is facilitated by two powerful IHC Holland HRMD 161-34-80 jet pumps, each with an output of 2,150kW.
For maintenance and assisting stores, there is a TTS-Norlift/CCL 1600-6024 deck crane on a gantry. This can lift 50/60t at a 22/18m radius.
DREDGER ENGINES
The HAM 318’s main engines consist of a pair of Wartsila12V46C units, which each have an output of 12,600kW at 514rpm. Each of these is connected to a Flender GUHQ 1450 gearbox, giving an output speed of 115rpm. These in turn drive a pair of nickel-aluminium-bronze propellers manufactured by Lips. These controllable pitch propellers are 5.4m in diameter and provide the dredger with a service speed of 17.30kt (100% MCR). Steering is assisted by means of two Becker FKSR-1-3700/880/620/1 free-hanging flap rudders. Two electrically driven adjustable Lips CT225-DPM bow thrusters are fitted at the forward end. These give an output of 1,100kW at 295rpm. Mooring is assisted by two windlass/winches located forward and an anchor winch aft. These hydraulic winches are manufactured by Brohl.
There is a power take-off from the main engine to two alternators. These are AMG 1120MRO6 units provided by ABB. These each have an output of 11,000kW at 11,000rpm. There are also two diesel-driven alternators. The first is a Wartsila 6L26A engine, coupled with an AMG 630 S6 unit manufactured by ABB. It has an output 1,840kW at 1,000rpm. The second is a Caterpillar/3512B DI-TA engine driving a Caterpillar/SR4 alternator. This has an output of 1,200kW at 1,500rpm. The main generators provide power to the sand pumps, the jet pumps, the dredging installation and other equipment on board.
The vessel is equipped with a very sophisticated control and computer system for the navigation and dredging processes. There are three Decca/JRC Radars – a Bridgemaster E250; an ARPA 343/12M/; and a JMA608HD. There is also a JRC NXZ 4570 DGPS satellite navigation system
The complement of the Ham 318 is 45 people, who are accommodated in 15 double and 15 single rooms. The Ham 318 is classified by Bureau Veritas under the notation 1 3:3 + Hopper Dredger (Deep Sea), AUT.MS.
