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66 Maritime Reporter & Engineering News ? AUGUST 2013 Another feature of the Siemens gear- boxes is that they are equipped with a top-mounted oil-supply system and an attached monitoring system for unsu-pervised operation. In addition, the propeller thrust bearings are built into the gearbox. For operation that means that the gearbox housings are designed to be especially torsion-free, thus en-suring a faultless tooth mesh in all con-ditions ? such as, rapid changes of load while running in bad weather. Multiple-Disk Clutches for Easy ServiceMultiple-disk clutches enable the en-gines of the twin-engine gearboxes to be engaged and disengaged. Because of the power boost, the Hannibal can reach a maximum speed of up to 27.5 knots. During servicing, one engine can be ß exibly disengaged, while the other remains engaged and drives the ship. The second important function of the multiple-disk clutches consists in using the power take-off (PTO) out- puts integrated into multi-engine gear- boxes.A PTO enables power to be gener- ated onboard the ship with a genera-tor. Thanks to these primary PTOs, the ship?s engineering team can maintain generator operation on the PTO, even when the propeller is disconnected. In the case of the Hannibal, however, this feature was not required, because the ship has its own power plant to feed its main supply. The example of the world?s largest ferry boat, which links the two conti-nents of Africa and Europe on a line between Tunisia, Italy and France, reveals two things: The need to trans- port large quantities of goods and large numbers of people is unchanged. At the same time, the limits of what is techni-cally feasible and what is economically sensible are pushed further out.For gigantic records like these to be set, reliable and efÞ cient drive solu- tions like the Flender Navilus GVLQ 2500 gearboxes by Siemens used here are needed. Ralf Meyersieck is with the Mechani-cal Drives business unit of Siemens AG.www.siemens.de/navilus TECHNICAL FEATURE GEAR TECHNOLOGY (Source: Siemens) Fig. 3: The design of the Navilus GVLQ 2500 large gearboxes is es- pecially torsion-resistant, thus ensur- ing that the gear pairs mesh consis-tently well, particularly when running through rough seas. MR #8 (66-73).indd 66MR #8 (66-73).indd 668/2/2013 11:01:05 AM8/2/2013 11:01:05 AM
