Feature 2 | PROPELLERS & THRUSTERS Clutch of orders for next generation Azipod


ABB’s second-generation Azipod system has been endorsed by Norwegian Cruise Line for the company’s latest stage of fleet development.


propulsion package for each of two 143,500gt newbuilds ordered at Meyer Werſt. Te 4000 passenger-capacity vessels will be the largest cruiseship ever to have come from a German yard. Market receptivity to the enhanced


T


design was previously expressed in Celebrity Cruises’ nomination of the system for a new Solstice-class vessel contracted with Meyer Werft, and in a Japanese project thought to involve a brace of ro-pax ferries. The 126,000gt Celebrity Reflection,


the fifth Solstice-class newbuild from the Papenburg yard, had originally been specified with first-generation Azipod VO drives, as selected for the four preceding ships in the series. However, once the


wo 17MW Azipod XO units have been chosen as part of a comprehensive power and


new version became available last spring, the order was changed to a pair of XO pod systems. The vessel has a double- occupancy passenger capacity of 3030 passengers and is due to be handed over in November 2012. Te decision to change the specification


was largely influenced by the possibilities offered in reducing both fuel consumption and equipment costs, since the use of XO drives enabled power to be reduced to 2 x 17.5MW from approximately 2 x 20MW. Maximum speed is about two knots


less than that of the earlier Solstice-class vessels, although the lower speed is partly a factor of the slightly larger dimensions of the fifth newbuild. The difference in power input has been achieved through the higher efficiency of the XO pod in spite of the reduced torque of the motor and the smaller propeller diameter.


released as


No details have as yet been officially to the Japanese project


involving the first order for the new design of Azipod, although this is believed to involve an Azipod CRP propulsion configuration for each of two newbuild ro-pax ferries. In such an arrangement, an X-series pod would be mounted directly behind, and with its integral propeller counter-rotating in relation to, a mechanically-driven shaftline propeller. The concept was first employed on the exceptionally fast, Shin Nihonkai ferries Hamanasu and Akashia, completed by Mitsubishi Heavy Industries in 2004. Shin Nihonkai has booked two similar


ro-pax ferries from Mitsubishi, for delivery in 2012. As with the earlier pair, the new ships will be distinguished by a high service speed of at least 27.5knots. NA


Addressing challenges of station- keeping in ice


With offshore exploration taking vessels out to further inhabitable places, being able to place the vessel exactly where you want it is of vital importance.


in deep water areas where mooring is either costly or impractical, presents new challenges and opportunities for station- keeping solutions. Te environmental matrix with which drill ships, support vessels and icebreakers have to contend in day-to-day operations is intensified by ice and ice driſt. While considerable experience has been


I 44


accumulated by the marine industries as regards dynamic positioning(DP) for exploration and production in open waters, practical know-how is as yet limited with regard to extended-period, precise position- holding in difficult, heavy ice conditions. Moreover, emerging market demand points


ncreased investment in exploration and development of oil and gas resources in the Arctic region, including projects


to a need for increased facilities offering DP systems for ice model testing to investigate the station-keeping behaviour of ice-going vessels and offshore units incorporating extensive thruster systems, notably drilling vessels. Against this back-drop, a collaborative


research project known as DYPIC(Dynamic positioning in ice-covered waters) has been launched under the European Union (EU’s) Era-Net Martec programme, with financial support provided by the German Federal Ministry of Economics and Technology(BMWi). Te project consortium has the remit of examining the performance of DP systems in ice, and delivering guidelines and procedures that will benefit future operations and technology.


DYPIC is a 30-month study due to be


completed in December 2012, in which Hamburg Ship Model Basin(HSVA) is playing a central role. The German organisation is joined in the project by French research institute Sirehna and Norwegian partners NTNU, Kongsberg Maritime, Det Norske Veritas, and Statoil. Once DYPIC has been completed,


HSVA will be equipped to carry out the most demanding model tests to evaluate station-keeping in ice conditions worldwide. This will allow systematic investigation of the boundaries of operations in different ice scenarios, and consequently enable industry users to better examine the feasibility of planned operations and solutions. NA


The Naval Architect July/August 2011


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68