‘Plug and play’ dredging for Russian pontoon

The multifunctional pontoon Litsa has been turned into a performing dredger overnight as Damen delivered an entirely prefabricated system. The pontoon is winning sand and simultaneously loading barges which continue to appear alongside in a hyper-efficient ongoing dredging operation required by the looming winter.

The Ø 650mm trailing pipe mines sand at a maximum 28m depth, where gas pipes are to be cleared. The starboard trailing pipe is fitted out with a submersed dredge pump, directly driven by a 700kW electric motor. The sand is pumped over deck to a discharge spreader located at portside. An uninterrupted carousel of barges sails alongside to be filled continuously. The sand production is closely monitored using the density and flow meter on board, and using the low mixture overboard connection.

The entire Damen dredging system has been designed as ‘plug and play’. This means that the installation of the various elements did not need dry docking or serious construction work. The gantries, winches and swell compensator were all equipped with their proper foundation. They were welded on deck and installation was completed. The trailing pipe elbow slides inboard and does not need a slide flange construction. The discharge spreader has its own winch and foundation, making it into a complete kit.

A number of easily transportable containers were also supplied, filled with vital gear. One 30’ container houses the diesel-electric set with frequency drive for the submersed dredge pump motor. A 20’ container houses the diesel driven jetwater pump, which feeds pressurized jetwater to the drag head. Another 20’ container was equipped with the diesel-hydraulic installation, which controlled the gantry cylinders, the winches, the swell compensator and the dredge valves. The swell compensator bottles were accommodated in this container as well.

At the bridge, a control panel was mounted with all controls of the diesels and hydraulics. Separate screens were fitted to show the trailing pipe position, the dredge pump performance and the dredger and drag head positions, all using Damen software.

The plug and play nature of the project was due to its operating location. The pontoon works in Northern Russia near the island of Nova Zembla, where the summers are very short and all dredging activity has to be completed before the ice returns.