VESSEL REFIT | Swalinge – Den Herder dredger boasts additional capacity and key equipment following overhaul

Dutch shipbuilder the Kooiman Marine Group has completed conversion works to upgrade the existing capacity of a trailing suction hopper dredger (TSHD) owned by compatriot marine projects company Den Herder Seaworks.

Swalinge was originally built as a coaster in 1977 and was rebuilt into a TSHD by Kooiman Marine after being purchased by Den Herder in 1996. The owner decided to modernise the vessel to enable it to better serve customers.

The recently completed works involved increasing the vessel’s length from its current 82.2 metres to 119.2 metres and expanding the hopper capacity from 1,800 cubic metres to 3,000 cubic metres. This necessitated cutting the hull in half and inserting a new section 37.1 metres long.

The dry unloading installation was designed and built to Alewijnse’s own specifications and delivers an average unloading time of 2.5 to three hours following the recent conversion. The hopper is fitted with bottom doors so it can rapidly dump sediment. It is also capable of using shore delivery installations for pumping sediment ashore.

Other upgrades include the installation of a second 450kW bow thruster to enhance lateral manoeuvrability, two spud poles, a newly designed bulbous bow, a new propeller nozzle around the thruster, portside and centreline conveyors from Stokman, and a hydraulically adjustable separator for the dredging system.

Alewijnse was also responsible for the complete electrical installation on board. The scope of work included extending the cables in the vessel’s hopper corridors, upgrading the main switchboard to accommodate the integration of the new bow thruster and hydraulic pumps, and the wiring and connecting of the complete dredging installation including the hydraulics system, jet water system, suction pipe gantries, and drain system.

Alewijnse also modified several subsystems such as the wheelhouse desk, the alarm, the CCTV systems, and all the lighting on board.

Even with all these modifications, Swalinge retains its ice class notation and other key attributes such as a 14.6-metre beam, a 30-metre dredging depth, a MAN B&W 8L27/38 2,720kW main diesel engine, and an array of suction, discharge, and jet water pumps and their dedicated motors.

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