First day at work for new Boskalis dredger

The twin screw, 5,600 cu/m trailing suction hopper dredger

Crestway

was deployed in routine maintenance dredging, along with

Cornelia

, the plough dredger

Norma

and

two survey vessels,

Shamroc

and

Geo Explorer

. Another of the company’s trailers, the

WD Medway II

, joined the fleet to begin capital dredging on the site of the Felixstowe South Reconfiguration of the container terminal.

The Crestway is one of two identical sisters to be delivered to Royal Boskalis Westminster this year by IHC Merwede Dredgers from two yards in the Netherl

and

s. Crestway was launched at the IHC Merwede yard in Kinderdijk in May 2008. The sister ship Shoreway was launched at IHC’s Sliedrecht yard in April. IHC Merwede specialise in the design

and

contruction of vessels for the dredging

and

offshore industries

Both ships are 97.5m LOA, with a breadth of 21.6m

and

a maximum draft of 7.1m. The gross tonnage is 5,160 tons with a deadweight of 8,350 tons.

Powered by two Wartsila 2,025kW main engines, they have a service speed of 12.8 knots. There is a third engine that can be coupled up to the dredge pump during shore discharge operations. The bowthruster is powered by a 450kW engine

and

the twin rudders are high lift Barkmeijers. The suction pipe is 1,000 mm diameter

and

the vessel can dredge to a depth of 33 metres.

The vessels have been designed for the dredging

and

transportation of s

and

and

sludge (silt) in shallow waters, which makes them ideally suited for the maintenance of harbours, beach replenishment

and

l

and

reclamation projects. The forward wheelhouse

and

accommodation block is a new departure for Royal Boskalis Westminster. The pronounced bulbous bow is designed for efficient steaming when fully loaded

and

has no significance to the dredging operation, but it does contain a 400 ton ballast tank.

With a crew complement of 13, the Crestway was working around the clock at Harwich. It is able to fill its hopper with more than 5,000 m3 of silt in less than half an hour

and

it can discharge in under five minutes. For the Harwich contract the spoil dumping ground is at the Inner Gabbard, which entails a 1 1/2 hour voyage each way. The low density silt is then dispersed by currents well away from the fishing grounds.

The Crestway

and

Shoreway are part of the Boskalis fleet expansion plan. There are also two more trailing suction hopper dredgers of up to 12,000m3 on order. At the end of 2007 Boskalis took delivery of the rebuilt jumbo cutter suction dredger the Phoenix. The extension of the Queen of the Netherl

s will transform it into a 35,500 cu/m mega-hopper, while various other specialist vessels are due to go into service between now

and

2012.

By Graeme Ewens