Boskalis Nordic Today No.02/2018-2019

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The flow of the River Aura carries into Turku’s harbour and main channel sediment that has to be removed at regular intervals. This ensures that the channel and the harbour basin maintain their officially stated navigation depth and safety. Terramare was responsible for the maintenance dredging in 2018.

dredging in which we used a lip plate fixed on top of the claws of the dredger’s buck- et. The channels’ dredging masses were mainly loose clay which, during dredging, was also studied for future stabilisation measures planned in future maintenance dredging,” explains Pöyhönen. “The Turku maintenance dredging went smoothly. During the work, we ensured at the same time that the Viking Line and Silja Line car ferries were able to operate un- hindered in the Port of Turku despite our dredging activities,” continues Pöyhönen. ICE BUOYS TO SPINDLE BUOYS Terramare’s contract also included the re- placement of sea marks in Turku’s main channel. This involved changing the old ice buoys with new spindle buoys. “We have replaced the old steel ice bu- oys with new plastic spindle buoys, which need less maintenance that ice buoys. The old steel ice buoys also needed regular maintenance painting, while the surface layer of the plastic spindle buoys is dyed throughout,” says Pöyhönen. “Replacement of the sea marks was im- plemented in cooperation with a subcon- tractor, Meritaito Oy. We lifted the old ice buoys out with a backhoe dredger and levelled the bottom, while Meritaito in- stalled the new spindle buoys precisely in position with its own channel maintenance vessel Seili. A total of 21 sea marks were replaced in the contract,” says Pöyhönen in conclusion. The Turku maintenance dredging and the installation of the new sea marks have now been completed. The River Aura will ensure, however, that the maintenance dredging is repeated every few years.

ICE BUOY STEEL

SPINDLE BUOY PLASTIC

10 m

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WEIGHT 10,000 KG

GRAPHIC: MARKKU SALONEN PHOTO 03: JOUNI SAARISTO, PORT OF TURKU

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WWW.PORTOFTURKU.FI

INTERNATIONAL MARINE EXPERTS | BOSKALIS AREA NORDIC | WWW.BOSKALIS.COM/NORDIC