German diesel engine manufacturer MAN, which has been field trialling engines aboard a Lake Constance catamaran has recently published the project’s first results regarding consumption and reliability.

Katamaran-Reederei, a subsidiary of Stadtwerke Konstanz and Technische Werke Friedrichshafen has been using the six-cylinder, 412 kW (560 horsepower) MAN D2676 LE432, an inline six-cylinder

In spite of their significantly reduced displacement compared to the replaced engines, the performance and dynamics have remained consistently positive, MAN claims. The reduced cylinder count and more modern engine technology, along with other factors, have resulted in improved consumption figures.

The catamaran Constanze needs eleven percent less diesel with the D2676 than with the previous engine. “In addition to the new engine, we have carried out other projects with a view to saving on fuel. In spite of the reduction in the ship’s resistance, the structure of the off-flow and the overhaul of the rudder, we can assume that the majority of the savings are linked to the engine”, said Christoph Witte, Managing Director of Katamaran-Reederei.

More than 15 percent was already saved last year due to an altered route. It enabled lower maximum speeds on the lake with the same timetable. “As is well known, the shortest path connecting two points is a straight line, which we have come slightly closer to achieving with the new route”, says Witte. Now a speed of 17.3 knots (32 km/h) is sufficient for the catamaran, instead of 21.6 knots (40 km/h), in order to cross the lake at 60-minute intervals. Due to the lower speed, the catamaran again uses less diesel.

The Managing Director is not worried about missing time reserves either: “We may and can still travel at 21.6 knots with the new engines. Therefore, it is possible to make up for a delay of eight minutes, which means that the craft always reach their destination on time”, says Witte.

As Katamaran-Reederei's craft are increasingly being used for local public transport on Lake Constance, the reliability of the engines is very important. “We cannot take the risk of the engines' breaking down. Many commuters travel with the catamarans, and they need to reach their place of work on time”, explains Witte. “High technical availability of the craft is the crucial precondition for this. The high reliability of the MAN units significantly assists us in this. In this way, we achieve a rating that is excellent for local public transport operations”, said the Managing Director. He added that in order to maintain this reputation, the reliability of the MAN engines is the most important factor, other significant advantages of the engine being its compact installation dimensions and its agility, which very much suit the catamarans. The developers of the MAN engines are also aware of this: “Through the state-of-the-art common rail injection technology, the D2676 registers a touch on the throttle very quickly and reacts immediately”, according to Stefan Löser, Project Manager for the D2676 marine engine. Furthermore, the engine is economically efficient. Christoph Witte quickly recognised the advantages during the course of the field trials: “As Managing Director, economic efficiency and reliability are naturally extremely important to me. Our customers, who rely on the punctuality of the catamarans, should not be disappointed. MAN has simply launched a good product on the market for us”, says the Managing Director.

Following the end of the second field trial, Katamaran-Reederei will receive the very first series-produced D2676 for marine applications in this performance class to roll off the production line in Nuremberg. The engine that will be used on Lake Constance is thus not just something singular in terms of its specialist configuration for workboat applications. “The D2676 is a modern, future-proof engine, which has been specifically modified for workboats. Its reliability and sophistication are based on basic engine components which have proven themselves in many millions of kilometres in HGV applications”, says Project Manager Löser.

Due to the positive cooperation between MAN and Katamaran-Reederei, the partners have extended the field trial, which started in May 2015, by a further year. Now that the first target of 3,000 running hours has been attained, the engine is to be tested for a total of 10,000 hours. “It is a partnership that both parties benefit from”, said Witte.

By Jake Frith