Japanese ro-pax melds experience and innovation

A new phase in the modernisation and upgrading of the Sea of Japan coastal passenger and freight traffic is signalled by Shin Nihonkai’s 25-knot ro-pax sisters. David Tinsley reports.

Reinvestment in Japan’s long-distance, coastal ferry services has been running at a high level for some years, and a clutch of large ro-pax vessel deliveries this year is set to be followed by at least six further vessels between now and early 2019. The sector is wholly controlled by indigenous companies, which have consistently met each stage of fleet modernisation through recourse to home yards, ensuring continuity of ro-pax ferry construction by the Japanese shipbuilding industry.

Functionality has long pervaded the extent and design of passenger facilities and service levels on Japanese ferries, but this is changing in favour of greater onboard comfort and a wider range and higher quality of amenities in response to society’s rising expectations, competition and the tourism potential.

The freight business underpins year-round operations in the primary long-haul ferry markets, entailing connections between the main, central island of Honshu and the islands of Hokkaido and Kyushu, in the north-east and south-west, respectively. The passenger traffic is variable, peaking during the summer months of June, July and August.

For the Japanese ferry sector as a whole, there is some way to go before the ‘product’ can be said to be on a par with the cruise-ferry standard applied on many shortsea routes in Europe. The business in Japan has long been associated with a conservative approach, whereby continuous improvement and refinement of proven designs and shipboard systems is the order of the day, and against a backcloth of different expectations on the part of Japanese passengers and society compared to their European counterparts. However, recent years have seen a stronger focus on the quality and extent of passenger facilities aboard Japanese ferries.


Shin Nihonkai’s latest vessels, commissioned into northern duty this year, provide a powerful expression of this trend in combination with the long-distance coastal operators’ propensity for harnessing home-grown energy-saving solutions and technologies.

The 31,389gt sisters Lavender and Azalea are the new mainstays of the Sea of Japan overnight service linking Niigata, on north-west Honshu, with Otaru, near Sapporo, on the island of Hokkaido. Lavender made her debut in March, joined by Azalea in June, both having been constructed by Mitsubishi Heavy Industries’ Shimonoseki yard at Honshu’s southern tip on the Kanmon Strait.

The latest ro-pax generation marries capacity for 600 passengers with a maximum freight load of 150 trucks or trailers, plus 22 cars, or other permutations of goods vehicle and accompanied car intake. Freight is carried on two decks at main and upper levels, with cars in the lower hold. Ro-ro access to the main deck is by way of an axial stern ramp, complemented by a ramp on the starboard quarter, while the upper deck has dedicated side access aft plus a turntable to assist truck movement through the right angle turn.

Shin Nihonkai has long pursued a vigorous fleet renewal policy, with Lavender and Azalea being the third pair of sister newbuilds introduced since the turn of the century. Certain elements of the design and configuration are indeed iterations of earlier generations. But the latest ferries encapsulate advances in form, systems and technology that result in ships that are fit-for-purpose in the context of year-round deployment in often challenging Sea of Japan conditions while also coupling a 25-knot service speed with enhanced operating efficiency and comfort.

The comparatively high speed, faster than that of the previous tonnage on the 692km (430-mile) Niigata/Otaru run, is the outcome not simply of specified power, but rather of power in combination with various design and engineering solutions to ensure the optimum translation of energy into propulsive effect.


The hull body lines have been crafted to maximise sailing efficiency, with the waterline length increased by a near-vertical stem. This imposing feature of Lavender and Azalea is designed to confer good seakeeping performance, reduce resistance and maintain speed in high or difficult seas. Other important and innovative measures to enhance hydrodynamic efficiency are the Proximity Twin-Screw System and the Mitsubishi Air Lubrication System (MALS).

MALS uses an electric motor-driven, special blower to produce small air bubbles along the bottom of the hull to create a carpet of air, reducing frictional resistance between the hull and the seawater during navigation. Air supplied from the blower is directed to chambers located at the outlets in the hull bottom, and immediately forms bubbles when it issues from the outlets due to the shearing force of the friction against the seawater.

The MHI-developed technology has been applied to a number of vessel types, including bulkers, cruiseships, and heavy-load carriers, as well as ferries. Even taking air blower power consumption into account, MALS is claimed to achieve net energy savings of some 4%-7%, depending on the specific application. The MALS reference list includes the two 23-knot ro-pax vessels built at Shimonoseki in 2015 for Meimon Car Ferry’s City Line service linking Osaka and Kitakyushu through the Inland Sea.

Powerful medium-speed machinery of well proven design is the order of the day in the fleets of ships that maintain Japan’s year-round, long-haul coastal ferry routes, with MAN’s Pielstick marque remaining a popular choice. In the case of Azalea, and as with Lavender, the propulsion installation is based on two 12-cylinder, vee-type Wartsila 38-series engines, driving twin, controllable propellers through Wartsila reduction gears. The Proximity Twin Screw System, incorporating shaft brackets, ensures a very small clearance between the tips of the outward-rotating port and starboard propellers, improving propeller loading and reducing cavitation.

The nominal maximum continuous rating of the 12V38 in its ‘C’ version is 8,700kW at 725rpm, making for a 17,400kW power concentration in Azalea. The vessel’s 25-knot service speed clearly reflects the effectiveness of the propulsion plant in conjunction with the specific shaftline configuration and hull lines, and the resistance-reducing, air bubbling system.

Although the 380mm-bore, Tier II-compliant W38 does not appear in Wartsila’s current listing of available engines, it has retained a following as a propulsion engine by virtue of a long track record dating from its introduction during the early 1990s as one of the most competitive and compact contenders in its market segment.

The W38 series was a result of collaboration between the Finnish company and Dutch technicians after Wartsila’s initial purchase of a majority stake in the former Stork-Werkspoor Diesel. Today, the Dutch interests are wholly-owned by Wartsila. Production of W38 engines was originally undertaken at the Zwolle factory in the Netherlands, but was subsequently transferred to the huge Trieste plant of Wartsila Italia.


The Wartsila 38 type, like the 400mm-bore Pielstick PC2.6B machinery employed in other, recent Japanese newbuild ferries, fulfils rigorous Japanese safety criteria for passenger-carrying vessels.

Shin Nihonkai’s latest ferries are each equipped with a Bilcon-X waste oil and bilge concentrator developed by the Japanese company Volcano. The plant employs the low temperature humidification and evaporation method of operation, and is claimed to significantly reduce treatment and handling costs entailed with oily waste and bilge water. In addition, the completely enclosed system obviates overside discharge, reducing environmental impact.

The faster speed offered by Shin Nihonkai’s new ships has resulted in a significant reduction in transit duration. This has been used to push back departure times in both directions, increasing the catchment period for freight while maintaining the same, very early morning arrival at Otaru on northbound voyages, especially important to hauliers. Whereas the schedule previously maintained by the 18,200gt sisters Lilac and Yuukari hinged on a 10.30 departure from Niigata, the new timetable entails an 11.45 sailing, still ensuring the 04.30 next-day arrival in Otaru. This makes for a 16 and three-quarter hour northbound voyage compared to 18 hours before.

Delivered by Japan Marine United in 2002, Lilac and Yuukari have been redeployed on one of the company’s other, long-haul Sea of Japan routes, that between Tomakomai, on Hokkaido, and Akita, Niigata and Tsuruga, on Honshu.

Sleeping accommodation on the Azalea is arranged over three decks in the ship’s forward section. Twin suites and the highest grade, Deluxe-A western-style cabins are located on deck 6. Public baths, a feature of large Japanese ferries, are installed in the midship interiors of deck 6 and, unusually, are adjoined by outside bathing pools. Deck 5 houses a mix of Japanese-style twin and four-berth rooms plus Japanese-style Deluxe-A cabins, while the lower accommodation grades are on deck 4 below, including capsule-style units. On the port side of deck 4, aft of the ship’s central, three-level atrium, is the dedicated freight drivers accommodation consisting of capsule berths.

Taking a leaf out of the book of the retail and services sectors, Shin Nihonkai has introduced an advanced form of customer interface on Azalea by posting a humanoid robot, Pepper, next to the information desk in the atrium area. Developed by the Japanese company SoftBank Robotics and its French subsidiary Aldebaran, Pepper uses voice and face recognition to provide passengers with information either verbally or through an integral digital display. Pepper robots for passenger interaction were introduced at sea last year by the Carnival Group’s Costa Cruise and AIDA brands.

At nearly 200m overall, Azalea and Lavender are the maximum length for the Shimonoseki slipway building berth. MHI completed an extensive modernisation programme for the yard in 2011, focused on boosting productivity in the construction of higher added-value areas in which Shimonoseki has a solid track record, including coastal service ferries, ro-ros, research ships and other special-purpose vessels.

Illustrative of the productive business relationship between shipowner and shipbuilder, Shin Nihonkai and MHI had provided the breakthrough application in 2004 for the innovative contra-rotating propeller (CRP) Azipod system in the large ferry sector. The recipients, the 224.5m single-skeg Akashia and Hamanasu, were constructed at MHI’s Nagasaki complex and commissioned on the 1,060km (659-mile) route between Maizuru and Otaru. With a service speed of 30.5 knots, and a maximum approaching 32 knots, the vessels are the fastest ro-pax ferries in Japan.


Length overall


Length b.p.


Breadth, moulded


Depth, moulded




Gross tonnage




Passenger capacity


Ro-ro capacity

150 trucks + 22 cars

Main engine power

2 x 8,700kW

Service speed

25 knots




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