Schottel propels EU river cruises

Specifically designed for river cruise ships five years ago, Schottel says its concept has proved popular thanks the benefits its offers owners including low-noise, shallow draughts, increased overall efficiency and energy efficient operation.

Splitting the propulsion units from the conventional two to four twin propellers reduces the draught of the vessel to around 1.60m. The company says this makes it easier for the vessels to sail smoothly, even in shallow waters.

Andreas Witschel, general sales manager, sales competence centre, Schottel, told Maritime Journal: “River cruise ships on European rivers are operated with a wide range of water levels, so it is particularly important to ensure that vessel operation can continue even when levels are low. Since the draught is approximately 1.60 m and the propeller diameter is only 1,050 mm, the clearance to both the structure of the vessel and to the river bed is highly favourable.”

The highly elastic moulding of the STP effectively damps the pressure impulses induced by the blades, and the reduced diameter of the propellers allows a spacious clearance between the propellers and the hull and results in a low structure-borne noise level.

The smaller propeller diameter of 1,050mm requires only minor tunnelling of the vessel’s stern. In contrast to high-tunnelled vessels, these effective designed stern lines increase the overall propulsion efficiency significantly.

In addition, the propulsion system with four Schottel twin propellers 200 has a low thrust-detection co-efficient thanks to the clearance between the propeller and hull, meaning almost the entire thrust can be converted into propulsive power.

One or two Schottel pump jets of the type SPJ 82 RD serve as additional drives in the bow.

Schottel says increased operational safety comes from the steering of the four-fold propulsion system. Just like a dual system, the steering is controlled via two joysticks, one for the two units portside and one for the two units starboard.

Apart from a few details, the bridge does not differ from a double unit. This way, captains can easily change between a fleet’s different vessels.

Safety is also guaranteed by the nine-fold redundancy of the propulsion systems: the four STP 200 main propulsion units each have redundant control.

Currently, the ‘concept’ is available with four mechanical STP 200 in both a diesel-direct and a diesel-electric version, as well as with four electric Schottel Combi Drives (SCD 200).

The Schottel propulsion portfolio for river cruise ships also includes a variety of tailored concepts for different river cruise providers. These range from the traditional concept with two Schottel twin propellers to river cruise vessels operating with Schottel pump jets as main propulsion units.

After this recent contract is completed, a total of around 40 European river cruise vessels will be equipped with the ‘concept’. Schottel told MJ it’s currently installed in vessels of the A-Rosa and Viking fleet.