Japan-based shipbuilder Namura Shipbuilding and compatriot owner NS United Kaiun Kaisha have partnered in a joint research project aimed at developing a wind-powered system for a 183,000 dwt capesize bulk carrier.
Namura has applied for a patent on a sail system in which extending sails are located under deck between the holds of a ship and employed whenever wind conditions are able to aid propulsion and so reduce fuel use.
In use, the sails are elevated above deck and can also be extended laterally to increase the sail surface and hence the propulsion effect. The sails can also be rotated so as to take better advantage of wind direction and gain maximum propulsion effect. When wind conditions are not favourable, or when the ship is conducting cargo operations, the sails are retracted and stored below deck.
In order to preserve the SOLAS mandatory line of sight requirements from the bridge on such a long vessel as a cape, the size and height of the sails will be optimised. This involves the height of the sails reducing from the wheelhouse towards the bows. Nearer the bows, the height can be increased but the width narrowed allowing vision from the bridge to remain unobstructed.
Last month the largest ship to date had wind propulsion kit fixed to its deck. Pan Ocean’s 325,000 dwt Sea Zhoushan very large ore carrier newbuild, due to go on charter to Brazilian miner Vale, is now sporting five white, 25 m high Norsepower rotor sails across its huge deck, installed at a yard in China.