Dalian trio ready to run

Faced with the need to modernise its roro fleet, Stena RoRo decided to base the design of its new vessels on the 1998-built Sea Centurion. This is the only completed example of the original 4-Runner type, delivered from the now defunct Italian shipyard Societa Esercizio Cantieri. The resulting design is the Stena 4-Runner Mk II class, of which three were ordered in early 1999 from Chinese shipbuilder Dalian Shipyard. The first unit in the series was delivered last month (November). The 12,300 dwt 3,000 lane-metre design claims to give optimum cargo flexibility and operational economy. By placing the order in China, the Gothenburg-based shipping company has endorsed the growing stature among north European roro shipowners of the world?s third largest shipbuilding nation. Increased capacity The capacity of the Dalian newbuildings represents an increase of more than 10% compared with the Mk I designed Sea Centurion, despite the latter?s slightly higher deadweight of 12,350t. According to Stena, this represents an increase in transport efficiency of about 19%. It is achieved through an additional length of 12.7m, which has also given the Chinese trio an extra half knot of speed despite using the same model of Sulzer medium-speed diesels. This higher speed capability (up to 22.5 knots) means that fuel consumption will be improved when the Mk I and Mk II vessels are travelling at corresponding speeds. The four eight-cylinder Sulzer ZA40S main propulsion diesel engines will provide a total output of 24,000kW. The engines are grouped in pairs to provide drive to two Kamewa CP propellers. Manoeuvrability is aided by the fitting of two bow thrusters. Opting for the same engines not only confirms the owners satisfaction with it performance, but also makes for greater overall operational efficiency through standardisation of components and skills. The prime movers for each of the three new ships were manufactured at Wärtsilä?s wholly-owned Italian plant in Trieste, a pointer to sharpened European competitiveness in medium-speed diesel production. The four-engine configuration permits one engine to be down for maintenance during the vessel?s regular operation, while still achieving a speed in excess of 20 knots. With only two engines engaged, the ship is expected to be able to sustain an 18-knot service speed at a consumption of 39t per day. The ships have been prepared for subsequent installation of selective catalytic reduction (SCR) equipment should future trading requirements or environmental expectations so dictate. Cargo flexibility Cargo flexibility on the three cargo decks is a key feature of the design. The weather deck and the lower hold have a free height of 5m while the main deck has a headroom of 6.8m over most of its length, increasing to 8.1m in the after-most part. In a short-sea ferry context, this affords an unusual degree of flexibility for outsize items and project cargo consignments. Commercial vehicles, Mafi trailers, cassettes and containers can all be accommodated throughout three deck levels. The main and weather decks offer similar trailer intakes of 1,190 and 1,280 lane metres respectively, with the 530 lane metres on the tanktop taking the total to 3,000 lane metres of 3m width. The revenue-earning potential of these vessels is also expressed in an overall freight deck area of 9,105m2. Stena RoRo?s inclusion of teu and feu container unit ratings (maximum 851 and 271 units respectively) for each of the decks emphasises the versatility built into the Mk II design. The vessels can also be retrofitted with an optional top deck which would increase their carrying capacity to 4,150 lane metres. Simultaneous loading All cargo handling will be concentrated over the 18m wide stern ramp which has a safe working load of 230t. The equipment design and system configuration has been conceived to permit simultaneous loading of all three decks via internal ramps. Flexibility is further enhanced through the facility to take dangerous goods on all deck levels, and through the availability of sockets for up to 100 reefer units on the main and weather-decks. In addition, the vessels will also have full double-hull protection of the main and tank top decks, will be fitted with flume stabilising tanks and meet the highest ice class 1A standard. As a supplier of tonnage to Stena Line and other operators, Stena RoRo anticipates that the trio of newbuildings will be available for trade in the first half of next year. The company has yet to confirm charter arrangements for the new trio, but indicated that the ships would most probably enter the northwest European traffic. The main deployment possibilities appear to be either a situation where the three newbuildings would supersede four existing vessels in a particular trading sphere, or a scenario where the three plus the returned Sea Centurion would provide pairs of ships as replacement capacity. n