Navigational aids are auxiliary equipment that ensure the safety of shipping as well as protect the waterways. Near the coastal area, navigational aids support shipping in several areas, e.g., in position determination and orientation or in detecting shallows and obstacles.
The floating navigational aids in the waterways on the western coast of Schleswig-Holstein include a multitude of fired and unfired buoys. During semi-annual maintenance, the buoy is cleaned of barnacles, mussels, and plant growth on board a buoy tender ship while its mooring chain hangs outboard and is secured together with the anchoring stone.
However, if the buoy has already been lying out for 2.5 to 3 years, it must be completely replaced for extensive repair work and repainting. The reason for this is that the greater the plant growth on the buoy, the deeper it lies in the water and the harder it is to see from afar – not to mention the contamination in the headwater area.
Changing the buoy requires it to be transported to the Tönning building yard, where it is lifted from a truck with the mobile telescopic crane 643 from SENNEBOGEN and put into storage with a pick & carry process. For this purpose, the buoy, weighing up to 6 t, is moved while freely hanging from a hook and taken to the storage area or the repair shop. Later on, the buoy is dismantled into individual parts with the help of the crane so that it can be cleaned of residue and sand-blasted. The maintenance work is completed when the buoy is preserved with four coats of paint. After reassembly, it is then placed in the waterway again by the buoy tender ship and put back into operation.
Crane operator Sönke Speck enjoys his reliable machine, the SENNEBOGEN 643, which he has operated with a special auxiliary jib since December 2016. "The crane has sufficient lifting capacity and can be moved very safely. The work movements can be carried out very sensitively, and I have firm control of every lifting and moving task."
"The last crane that we used had seen better days and did not have enough load capacity and stability for use as a pick & carry machine. The dual tires and the considerably better load capacity of the new SENNEBOGEN offer a safer and better solution. The overview from the maXcab comfort cab is also ideal for work with the machine," emphasizes Jens-Peter Dühn, the director of the building yard at WSA Tönning.
An important factor for winning the tender was that the crane operators could manage the machine well and were satisfied with the comfort. The crane operators were able to get an idea of this during trial operation in summer 2016, when the sales and service partner Friedrich Niemann from Kiel, Germany provided them with a suitable machine for test purposes. The employees of Friedrich Niemann also take care of the maintenance and servicing of the machine.
The mobile SENNEBOGEN telescopic crane 643 is used to put all buoys at WSA Tönning into storage, take them out of storage, as well as dismantle them for maintenance purposes.
With a load capacity of 40 tons, the 643 telescopic crane always has enough reserve for handling the navigation aids, which weigh up to 6 tons – at the same time, the compactness of the machine is important for driving into the narrow and fully storage areas.
The mooring stones, which weigh up to 5 tons, are also safely lifted and placed. The rough weather requires buoys, stones, and chains to be checked and replaced according to a prescribed maintenance plan.
As a full-time crane operator, Sönke Speck and his substitute are responsible for the safe handling of the buoys at the Tönning building yard and ensure that the repaired buoys are safely loaded, so that they can be laid out to mark and protect the waterways.