MAN propeller excels in bulker trials

30 Sep 2015
Sea trials for newbuild bulkers 'Elsabeth C' and 'Mirela' showed the fuel-saving benefits of MAN Alpha Kappel fixed-pitch propellers

Sea trials for newbuild bulkers 'Elsabeth C' and 'Mirela' showed the fuel-saving benefits of MAN Alpha Kappel fixed-pitch propellers

One of the first commercial applications of MAN Diesel & Turbo’s new fixed pitch propeller design, combined with a higher propeller layout and MAN’s new recommended light running margin (LRM), has achieved good results on the first of a new bulker series for Lemissoler Navigation Co.

As reported, the eight supramax bulk carriers, each of 58,000dwt, are to be fitted with single MAN B&W 5S60ME-C8.2 engines (with a specified maximum continuous rating of 8,050kW at 89rpm). They also feature MAN’s latest design of Alpha Kappel fixed-pitch propeller, with four blades and a diameter of 6.8m.

The first and second in the series of ABS classed, 186.5m loa ships – Elsabeth C and Mirela respectively – have completed sea trials off the coast of China, with Lemissoler subsidiary Frontmarine Co reporting considerable fuel savings compares to conventional propellers.

Frontmarine reports that both vessels consumed an average of 23 tonnes of fuel per day at a speed of about 14.2 knots in ballast conditions during the trials. The Elsabeth C also performed a successful crash-stop test that was notable for its lack of noise and vibration.

The vessels also applied MAN’s recently issued new guidance on light running margins, the ratio between shaft speed and shaft power (as a percentage of SMCR) under ideal sailing and vessel conditions. MAN increased its LRM recommendations in May, to give greater available engine power for acceleration and heavy weather in light of lower installed power – a trend the company highlighted as a response to slow steaming and power restrictions under the International Maritime Organisation’s Energy Efficient Design Index (EEDI).
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Thomas Leander, head of propulsion at MAN PrimeServ Four-Stroke in Denmark, said: “A key point during the design stage was to address the problem experienced by similar vessels that experience an overly-small light running margin. Therefore, MAN Diesel & Turbo recently introduced new light running margins for all FP propellers and two-stroke engines of 4-10%. Furthermore, the propeller layout for these vessels is 3-4% higher than normally applied to these vessel types. MAN Diesel & Turbo has managed to ensure safe and reliable operation, while improving the vessel’s efficiency and manoeuvrability during its lifetime.”

The Elsabeth C and Mirela were constructed by New Times Shipbuilding Co in Jiangsu, China and are scheduled for delivery in September 2015. The remaining vessels are scheduled for delivery over the following year.

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