Boskalis Nordic Today No. 01/2019

a challenge in implementing the erosion slab cast at the bottom of the quay,” says Juslenius. The elements, which were slipform cast last year, awaited installation over winter at their casting location on a broad end embankment in Mussalo Harbour’s A and B quay areas. Their size means that they have to be lifted, transported and installed using a high-performance floating crane. “We are carrying out the transport and installation of the elements with the self- propelled floating crane Maja, which has a rotating boom. It facilitates precise con- trol of the massive elements. The crane can also transport elements on its own deck, which increases the efficiency of transfer work,” says Juslenius. “The installation of the elements is im- plemented as teamwork, in which meas- urement and surface personnel and con- struction divers are involved in addition to crane operators. Although these huge ele- ments are an impressive sight above sea level, ultimately they will be hidden after installation under the waves on the quay line,” adds Juslenius. The 220-metre retaining quay wall is part of an extensive contract in which a completely new D harbour section will be built for the use of an UPM pulp terminal, which will start operating beside it. The contract includes, in addition to the quay work, extensive dredging of the harbour basin to a minimum depth of −17.5 metres, and a 620 metres long, four metres high breakwater. “I’m responsible for the quay worksite. Implementation of the dredging and break- water is the responsibility of our Site Man- ager Reijo Kultalahti . All in all, this is an extensive site where professionalism, experience and problem-solving ability are required. And it is precisely these fac- tors that make this a motivating and fasci- nating project,” concludes Juslenius. In addition to backfilling and a coping beam, the D section quay work includes both surfacing work and full installation of quay accessories. Erosion slabs will be im- plemented in front of the quay. There quay will be completed by the end of October this year.





RELAXED CONFIDENCE AND HUMOUR ARE THE SECRETS OF A GOOD SKIPPER´ B lasted rock filling of the new breakwater at Mussalo Harbour’s D section is being carried out using humour are secrets of a good skipper – it pays to keep calm,” says Nåhls.

“The challenging nature of the job makes the work interesting, however. Of course, there’s a lot of technology to help, such as sounders, positioning systems, autopilot and powerful thrusters, but vigilance is an absolute requirement as far as surrounding traffic, other work vessels and the weather are concerned. A sharp eye and anticipa- tion are positive qualities for a skipper, and go a long way towards doing the job well. In hard winds, heavy swells and challenging visibility, you have to consider whether conditions are safe – and that’s the barge master’s decision. On the other hand, perfectly clam weather, beautiful views and long sailing journeys are highly rewarding,” says Nåhls with a smile. Nåhls, who comes from Vaasa, also enjoys the sea in his leisure time, when he sails his own boat to his archipelago cabin. “My work for Terramare is periodical, so the occasional longer leisure-time inter- ludes enable me to enjoy relaxing moments sailing in the Vaasa archipelago and at my cabin. I always head there when I’m on a break from my skipper’s work,” says Nåhls in conclusion, as he sets off to fetch a new load of blasted rock.

barges, one of which is operated by the experienced Barge Master Ari Nåhls . Assisted by the backhoe dredger Nordic Giant, the large barge Terra 1, loaded with blasted rock, approaches the breakwater filling location. The vessel’s big split-hop- per pontoons open and the blasted rock falls into the precisely determined sector. The skipper, who has been in Terramare’s service for two decades, has experience ranging from the Mediterranean to north- ern coastal areas. Challenging projects and experience of different types of ves- sel have established Nåhls as a respected professional. “These kinds of split-hopper barges that float on pontoons are challenging to op- erate, because loaded or empty they be- have like different vessels. When empty, the vessel it is susceptible to winds and when loaded its steering requires anticipa- tion, particularly in shallow waters. Also, the composition of the cargo, whether it is solid blasted rock or loose silt, affects the stability of the vessel. An additional chal- lenge is posed by shallow shore locations, where propeller bottom contacts must be avoided. Accomplished skill and experi- ence, good awareness of the vessel’s be- haviour as well as relaxed confidence and


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