Big jump on the Upper Rhine
Whether downstream or upstream, where water is dammed, ships need to overcome height differences. As part of the renewal of the concession for the Ryburg-Schwörstadt power station, the boat transfer facility there was renewed in 2018. The crane manufacturer Innokran installed two crane systems with hoisting technology from STAHL CraneSystems.
On its 1,232.7 km journey from its source in Switzerland to its mouth in the North Sea, the Rhine covers an altitude difference of 2,345 metres. In the Upper Rhine region alone, the approximately 150 km long section between Lake Constance and Basel, the water drops by a total of 150 m. This relatively steep gradient results in numerous rapids, such as the Ettikoner Lauffen, and waterfalls, such as the Rhine Falls near Schaffhausen – the largest waterfall in Europe. The water of the Rhine and its energy are much in demand: the Upper Rhine is used for small boats, is a popular excursion destination and in summer a paradise for canoeists and kayakers. At the same time, eleven barrages and twelve hydroelectric power stations produce environmentally friendly electricity – a challenge for smooth shipping traffic.
The Ryburg-Schwörstadt power station is located at kilometre 143. With a capacity of 120 MW, it is the largest hydroelectric power station on the Upper Rhine. The weir of the power station is located on the Swiss side of the Rhine, the machine hall on the Baden side – meaning the power station lies exactly on the state border. Thanks to a pedestrian crossing, the border between Germany and Switzerland can easily be crossed by pedestrians and cyclists above the water. However, the barrage of the power station – like any barrage – represents a barrier for boaters and fish migrating upstream: those who travel on and in the Upper Rhine have to overcome a height difference of 10.6 m between the tailwater and headwater sides at the Ryburg-Schwörstadt power station. To make this possible, extensive fish ladders have been built for the fish, and there is a special boat transfer system for the ships.
Previously, a rope winch was used to transfer the boats from the tailwater to the headwater. It pulled the boats out of the water via an inclined ramp. The boats were then transported to the re-entry point on a roller conveyor. In the course of the concession renewal for the power station, the complete transfer system was also to be redesigned. The Swiss company Inauen-Schätti AG was responsible for the conversion measures. Inauen-Schätti AG commissioned the German company Innokran GmbH to build the transport system. Innokran GmbH has been a certified crane building partner of STAHL CraneSystems for many years and offers all crane construction work from planning through production to assembly. “Initially it was planned that we would only supply the drive components for the new transfer system. After several discussions with Inauen-Schätti AG, however, a complete design and construction of the transfer system by us turned out to be the most sensible solution,” recalls Klaus Fetzer from Innokran. “In February 2018, the concept of the system was ready with a portal crane on the tailwater side and a pillar jib crane on the headwater side.”
The boats are lifted ashore from the landing stage at the headwater. A 6.47 m high pillar jib crane with a load capacity of 4,000 kg and a reach of 6 m was installed for this purpose. An ST 50 chain hoist from STAHL CraneSystems lifts the boats out of the water. When the boats are on land, they are transported in a vehicle approximately 100 m past the weir to the entry point at the tailwater and then lowered back into the Rhine. For this purpose, a stationary portal construction was erected. On the water side the portal is 20 m high, on the land side only 6 m high. The length is 20 m. Innokran installed a specially manufactured double girder suspension crane with a span of 5.40 m on it. Two stationary SH 40 wire rope hoists from STAHL CraneSystems, each with a load capacity of 2,500 kg, safely lift the boats back into the water using a lifting beam. The wire rope hoists can be used individually or in tandem operation with the help of a radio control system. A maintenance walkway on both sides facilitates inspection of the system. “To ensure smooth operation in all weather conditions, the hoists and controls of both systems are equipped with standstill heaters and weather protection roofs,” explains Klaus Fetzer.
Boats up to 15 m long, 2.20 m wide and with a total weight of 2,000 kg can be transported with the new transfer system without any problems. Five months after the order was placed, the new system went into operation in July 2018 and proved its worth directly in the high shipping season.