Sulzer Diesels Power First Combined Ro/Ro Mini-Bulk Carrier On Inland Waterways Of Europe
The first combined roll-on/rolloff mini-bulk carrier/inland motorship in Europe—the RoRo-Simmental— belonging to the Swiss company Rohr- und Saar-Kohle AG, was recently commissioned. The vessel is 95 meters long (approximately 312 feet), about 11 meters wide (36 feet), and with a deadweight of 2,400 tons, has a draft of 3.45 meters (11 feet). With this first ro/ro ship for inland waterway traffic, heavy cargoes can be transported by way of an inclined ramp directly in the cargo space. The trimming tanks are brought into use during the loading and unloading operations. Hydraulic winches are employed to pull the cargo onboard. Turbines, transformers, boiler, chemical plant components, and other large installation equipment items can thus be loaded or unloaded at any desired location without the use of large special cranes. The RoRo-Simmental can also transport solid fuels in European inland waters.
As is the case for the vessel as a whole, emphasis is placed on the economy of operation for the engine installation as well. The call for a robust and comparatively simple layout, together with optimal reliability of operation, has been able to be met by means of Sulzer A-type diesel engines. These machines have already proven their worth in over 2,000 installations as prime movers for fishing, special and inland vessels, or as auxiliary generating sets on large oceangoing ships.
The Haslital, a previous newbuilding for the same owners, is equipped with two engines, type 6AL25/30, which each have a rating of 735 kw at 720 rev/min. As a result of further development and uprating in power, it was possible to select the smaller type 6AL20/24 for the Simmental, and to retain the same engine room conception.
In this way, powerful engines— designed according to the latest knowledge for continuous operation— may be installed in a relatively small space. Good accessibility for inspection purposes and overhaul work on the main engines, as well as other components, was decisive for the overall layout of the engine room.
Consequently, a two-engine installation (twin-shaft arrangement) with Sulzer four-stroke engines, type 6AL20/24, having the following data was selected for the total power requirements: Design principal—trunk-piston engine with supercharger, nonreversible; Bore/stroke—200/240 mm; Number of cylinders—6; Mode of operation— four-stroke; Rating—620 kw (840 bhp), and Speed—1,000 rev/min.