Skipping Constraints CRP Azipod® Propulsion Creates New Business Opportunities for Shin Nihonkai Ferries of Japan Lars Anderson, Thomas Hackman
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Ingenuity on the move Skipping constraints CRP Azipod® propulsion creates new business opportunities for Shin Nihonkai ferries of Japan Lars Anderson, Thomas Hackman hin Nihonkai Ferry, SNF Factbox 1 , Swas the first company to open a ferry route in the Sea of Japan in 1970. It was the first to operate large high-speed ferries. In 1995, it had the two ferries, Suzuran and Suisen, built Shin Nihonkai Ferry, the leading ferry operator in Japan, took delivery of with maximum speeds of 31 knots. two innovative new-builds in 2004. The new RoPax (roll on – roll off passen- Another example of SNF’s innovation ger) ferries were the first vessels in the world to be installed with ABB’s was when it selected contra-rotating Contra-Rotating Azipod® propulsion. In their first months of operation, the propulsion (CRP) with electric “pod” ferries documented a remarkably improved fuel efficiency and transporta- propulsion [1] for their two large high- tion economics. speed ferry new-builds. The largest and fastest ferries in Japan The two newest additions to the SNF fleet, Hamanasu and Akashia, were delivered by Mitsubishi Heavy Industries (MHI), Nagasaki, in 2004. 64 ABB Review 3/2006 Skipping constraints Ingenuity on the move With an overall length 224.5 meters, CRP Azipod propulsion, an azimuth- in the marine industry’s attempt to and with a service speed of 30.5 knots, ing 17.6 MW Azipod unit installed in a seize the full benefits of contra-rotat- these two RoPax ferries are the largest contra-rotating mode, aft of the main ing propulsion Factbox 3 . and fastest in Japan Factbox 2 . They are propeller 1 . also the first vessels in the world to Deliveries from ABB Marine included take advantage of ABB’s contra-rotat- There is always a risk involved when a 17.6 MW Azipod unit for each of ing Azipod® propulsion system. building a prototype. But, as CRP pod the two ferries, working in tandem propulsion was the only solution able with a reduction-gear-driven CP (con- Major benefits from CRP pod to achieve a 24-hour schedule and a trollable pitch) pod propeller. ABB propulsion daily ferry service, the decision to go also delivered the control systems and Shin Nihonkai Ferry operates an ahead with the CRP Azipod propul- the 27-MW, 6.6-kV power generation extensive network of ferry routes sion was taken. In doing so, SNF and and distribution systems. between the islands of Honshu and MHI broke the decades-long deadlock Hokkaido in northern Japan. The layout of the propulsion The main reason for choos- plant features two Wärtsilä Factbox 1 Shin Nihonkai Ferry Co., Ltd. ing CRP Azipod® propulsion 12V46 engines driving a CP was the increasing cost of propeller through a twin-in/ Trade name Shin Nihonkai Ferry Co., Ltd. bunker fuel. But a number single-out gearbox. Another Personnel 585 (land 231, sea 354) of additional benefits were pair of 12V46 engines drives Head office Osaka, Japan also gained. alternators that feed electrical Branch office 9 offices in Japan President Yasuo Iritani power to the Azipod unit. At 573 nautical miles, the Main group companies Kanko Kisen, Hankyu Ferry, The power distribution is Maizuru-Otaru route is the Kampu Ferry, Orient Ferry, 25.2 MW on the CP propeller longest in the network. Be- Japan Cruise Line, Kyowa Shoji and 17.6 MW on the Azipod, cause of its length, the route making 42.8 MW in total. In had always required three order to achieve the same ferries to provide a daily ser- vessel speed, a conventional Factbox 2 Ferry specifications vice. These three ferries, op- twin-shaft propulsion system erating at 20 knots, covered would require a total installed RoPax ferries Hamanasu and Akashia the distance in 30 hours and power of approximately Length 224.82 meters were able to keep consistent 47 MW. Breadth 26.0 meters arrival and departure times Depth, to 2nd deck 10.0 meters in both ports. Draught 7.4 meters Demanding weather Gross Tonnage 34,131 tons conditions In order to provide a daily Deadweight 6,649 tons The weather conditions in the service with only two ferries, Passengers 820 persons Sea of Japan can be divided the vessels needed to be Passenger cabins 144 pcs into two distinct seasons, win- larger and able to maintain a Trailer 158 pcs ter and summer. The winter cruising speed of 30.5 knots. Private car 65 pcs season lasts from November Shin Nihonkai Ferry had Max speed 32.04 knots through March and, during been investigating how this Service speed 30.5 knots this time, the Sea of Japan is might be achieved, but real- Power, installed 50,400 kW infamously stormy. The air ized that the cost, in terms Propulsion power, total 42,800 kW temperature can drop below of fuel consumption, at Azipod® unit 17,600 kW zero and, even though the sea these speeds would have never actually freezes, ice been prohibitive. ABB Scope of Supply per vessel build-up on ships can be a 1 × 3,450 kVA, 6.6 kV main generator problem. The winds during For a two-ship solution to 2 × 14,353 kVA, 6.6 kV main generators the winter storms often reach be viable, a remarkable (yet 3 × neutral point cubicles speeds of more than 30 m/s, realistic) reduction in fuel 3 × voltage regulator cubicles with waves in excess of eight consumption would have to 1 × 6.6 kV main switchboard meters high. be demonstrated to SNF. 2 × propulsion transformers 1 × excitation transformer Shin Nihonkai normally de- When presented with the 1 × propulsion converter lays or cancels ferry depar- ® CRP Azipod propulsion con- 1 × 17.6 MW CRP Azipod propulsion system tures when the height of the cept, which promised high 2 × thruster motors waves exceeds 5 meters but, fuel oil cost savings, Shin 2 × distribution transformers because of the length of its 2 × propulsion transformer pre-magnetizing device Nihonkai Ferry became routes, weather conditions 2 × UPS interested. After intensive vary and ferries can be de- 1 × CRP propulsion control system research, MHI chose a sin- layed by unexpected storms. gle-skeg hull solution with Maintaining a high average ABB Review 3/2006 65 Skipping constraints Ingenuity on the move speed is essential: a reduction in us to recover the initial expense,” he our operations, we are also opening speed of as little as 1.5 knots can explains. Mr Iritani also comments up new market opportunities.” cause an hour’s delay on this route. that, with the new ferries, SNF has achieved its main objective of operat- Fuel consumption reduced During the summer season, the weath- ing a 24-hour service on the Maizuru- by 20 percent er is calmer but the ferry routes are Otaru route. The target for Hamanasu and Akashia prone to relatively frequent typhoons. was to make a 10 percent saving in These are fairly easy to predict as they Compared with the exist- fuel oil consumption, as compared to tend to be slow moving. Nonetheless, conventional twin-screw ferries. a ferry can be forced to sail through a ing service, the vehicle typhoon to maintain the daily service. turnaround time is In May 2004, Hamanasu was the first ship to embark on the much-anticipat- Built to expectations reduced by 25 percen. ed initial sea trials. In the speed tests, Mr. Yasuo Iritani, President of Shin with a power split of 55 percent for Nihonkai Ferry, explains that he “Compared with the existing service, the forward propeller and 45 percent decided to go ahead with the project the vehicle turnaround time is re- of the aft, the vessel logged a maxi- based on the positive result of their duced by 25 percent, which is attrac- mum speed of 32.04 knots – a remark- studies of the concept. tive to cargo distributors. For exam- able achievement. ple, the reduced transportation time “The ships are somewhat more expen- makes us an alternative to air cargo Even more remarkable was the fuel sive than conventional ferries but the for high-grade perishable foodstuffs. oil consumption, which set a new operational savings are big enough for This means we are not only improving benchmark in the industry. The sea Factbox 3 General benefits of contra-rotating propulsion There are two main reasons for owners to The Route: The Azipod® unit also serves as a rudder, consider contra-rotating propulsion. One is Daily service between Maizuru – Otaru: smoothing out flow and increasing power. improved efficiency by being able to absorb 573 NM This improves steerability, especially at low rotational losses with the contra-rotating aft The options: speeds, facilitating maneuverability in harbor propeller. Contra-rotating propulsion also 3 ferries – 20.0 knots, 30 hours and reducing docking time. gives the benefit of thrust load distribution 2 ferries – 30.5 knots, 20 hours over a larger number of propeller blades in a The challenge: high power needs with high Shin Nihonkai Ferries – confined space. The added total blade area fuel costs Generic Machinery Arrangement results in improved cavitation characteristics, The solution: The four-bladed main (CP) The total propulsion power is 42.8 MW with by which more power can be fed to a CRP propeller with a diameter of 5.6 meters and 25.2 MW (60 percent) distributed on the for- propulsion system with smaller diameter an Azipod® propeller with a diameter of ward propeller and 17.6 MW (40 percent) on propellers. This is especially important for 4.8 meters and 5 blades. the Azipod unit. powerful shallow-draught vessels.