Japanese telecoms group KDDI is anticipating the development of offshore windfarms with the order of a vessel equipped not only for fibre optic cable installation and repair but also for laying subsea power lines. David Tinsley reports.
The 111-metre cable layer has been ordered from Colombo Dockyard in Sri Lanka, and thereby represents a rare case of a Japanese shipbuilding contract being placed overseas. In terms of both contract value and vessel length, the project is the largest ever undertaken by the Colombo yard, which has a Japanese operational connection by way of the tactical collaboration maintained with Onomichi Dockyard since 1993.
The vessel is due for completion by the end of March 2019, and will be deployed by KDDI’s wholly-owned subsidiary Kokusai Cable Ship Co (KCS). The newbuild scheme draws on specialised areas of foreign expertise, engaging Vard Design of Norway for ship design, Vienna Model Basin of Austria for tank tests, and the UK company MAATS Tech for the 2,000t underdeck cable carousel and spooling system.
Since its establishment in 1966, KCS has deployed cable layers for use in building and maintaining the optical submarine cable network across the Asia Pacific region. Two vessels are currently in service, the 133m KDDI Ocean Link and 109m KDDI Pacific Link, dating from 1992 and 1993, respectively.
The new ship will be the first in the Japanese fleet capable of power transmission cable installation in addition to the primary task of supporting work with telecoms cables. Furthermore, improvements in endurance and speed relative to the previous ships will confer a global, rather than simply a regional, operational capability. The nature of the hull form, thruster propulsion system and use of passive roll reduction tanks are intended to enhance seakeeping performance, directional stability and position holding in all conditions, extending the operating window for precision work.
The KCS newbuild will be a derivative of the VARD 9-01 design, first employed for the 100m Pierre de Fermat, delivered by Vard Brattvaag in 2014 to Orange Marine of Marseilles.
The heart of the diesel-electric power and propulsion plant will be four generator sets of 2,250kW apiece, and a DP2 standard of dynamic positioning will apply. Anticipated bollard pull is 80 tonnes. Three of the aggregates will be sufficient to cope with maximum energy requirements, conferring redundancy in the interests of ship reliability and safety, while transits between work locations will usually be made at economic speed with just two sets running, bringing fuel consumption down.
Hampshire-headquartered MAATS Tech, a leading designer and supplier of cable lay and flex lay vessel carousels and deck spread equipment, is providing the 2,000t carousel and associated gear. The company worked closely with Vard, Colombo Dockyard and the Japanese client to achieve the requisite design optimisation and integration of mission equipment, so that KCS can respond to the anticipated growth in Asian demand for subsea power cable installation.
The vessel’s cable tanks will afford a total 5,000t cable carrying capacity. Her outfit will include a dual cable lay system, A-frame, hydro plough and trenching ROV (remote-operated vehicle). All work is conducted from the stern, as is the mode in modern cable layers, eschewing the bow sheaves that characterised older, conventional cable ships.