The Naval Architect: May 2020
With much of the world on the brink of coronavirus lockdown in late March, the CIMC Raffles shipyard in Yantai, hosted a steel cutting ceremony took place for what will become the world’s largest LNG-powered roro upon delivery. The 242m long, 35.2m wide vessels MegaRoRo vessels, which will have a maximum speed of 20 knots, 27,000 dwt, and 5,800 lm capacity will also be the largest ships of their class in the world.
The order for two of the MegaRoRo series, which includes an option for two more, is the first to be placed by Wallenius SOL, a joint venture formed by operators Wallenius Lines and Swedish Orient Line (SOL) in April last year. The new company will transport forestry products and other goods around the Gulf of Bothnia, Baltic Sea and North Sea, strengthening the Finnish and Swedish forestry industries, and has already secured commitments from paper and card producers Stora Enso and Metsä Board. One of the principal drivers behind the Wallenius SOL is operational efficiency through sustainable transportation.
To help realise this, the company is investing heavily in new vessels which it believes will reduce its environmental impact. In addition to being LNG fuelled and other eco friendly features, the new vessels are to be built to Finnish/Swedish ice class 1A Super standard, allowing for year-round operation, even in the Gulf of Bothnia, where the temperature can descend to -35ºC and produce hazardous ice banks.
According to Carl-Johan Söder, naval architect at Wallenius Marine, the development of the vessel began with a brainstorming session to consider the size, machinery and ramp systems the vessels would require. “We drafted up different concepts in CAD at an early stage. But we also used simpler methods. We built a model of the ships’ loading ramps with pieces from a shoebox,” he explained.
The particular requirements of the wood pulp and paper industries, such as standard paper cassettes and extra-large containers, were all crucial in determining the ship’s initial design, as were optimising fuel efficiency. Wallenius Marine’s design team also spent time at Aker Arctic’s ice testing facility in Helsinki, where a 7m model was driven through water with artificial ice.
“We tested the vessel’s capability to follow and break out from a channel in extreme ice conditions and ability to penetrate thick ice ridges… We have a bulbous bow which cracks the ice from below, and a stern which pushes down ice floes when the vessel turns. This is advantageous when the ships are carrying lighter loads,” said Söder.
Other characteristics include a 5m ice-reinforcement belt above and below the waterline, which runs higher and deeper at the prow. Larger bilge keels have been incorporated instead of a flap rudder, given the risk of ice damage to moving parts.
As the concept further evolved, Knud E. Hansen was contracted to develop the specifications for the shipbuilding tenders. In recent years, the Danish naval architecture firm has developed considerable expertise in the large RoRo sector, working on such projects as the ongoing G5GG series for Grimaldi and a 6,700 LM design for DFDS, both of which were built at the CSC Jinling shipyard.
However, after visiting a number of facilities across the world, the contract was awarded to CIMC Raffles. Plan approval and classification will be undertaken by Lloyd’s Register, for eventual registry under the Swedish flag.
In January, the contract to supply the LNG fuel-gas supply systems was awarded to MAN Cryo, MAN Energy Solutions’ marine LNG fuel-gas-system manufacturer. MAN Energy Solutions has also been selected to supply 2 × 9L28/32DF dual-fuel auxiliary engines for each vessel. Under the agreement Man Cryo will provide 2 × 685 m3 ‘Type C’ vacuum tanks including tank connection spaces (TCSs) with LNG fuel pumps, bunker stations with a capacity of 500m3/h and automation, emergency shut-down and gas-detection systems.
Delivery of the first two vessels is scheduled for the latter part of 2021.
