Design for Wind-Assisted Bulker Storing Sails Below Deck
Japan’s Namura Shipbuilding Co. has become the latest shipbuilder to announce that it is developed a concept for wind-assisted propulsion to be installed on bulk carriers. In the joint project with operator NS United Kaiun, the companies are aiming to develop fuel-efficient technology using sails to make use of wind power.
Namura said that it believes that fuel-efficient technology using wind power will become an indispensable technology in the future. The shipbuilder highlighted that the Japanese government has set a target for the domestic shipyards to reduce greenhouse gas emissions by 46 percent by 2030 as part of the global initiative to address climate change.
As part of its design concepts, Namura said that it has applied for a patent on a sail system. They are proposing to store the retractable sails, when not in use, below deck in the holds of the ship. 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 to take better advantage of wind direction and gain maximum propulsion effect. When wind conditions are not favorable, or when the ship is conducting cargo operations, the sails are retracted and stored below deck.
The size and height of the sails will also be optimized to meet the SOLAS line of sight requirements from the bridge. According to Namura, the height of the sails will reduce from the wheelhouse towards the bow. Nearer the bow, the height can be increased, but the width narrowed allowing vision from the bridge to remain unobstructed.
The initial intention is to install the system on a 183,000 dwt bulk carrier.
The larger, slower moving bulk carriers are one of the industry’s early targets for the use of wind propulsion. Among the efforts, bulk carrier operator Oldendorff Carriers is participating in a joint development project to design and test wind-assisted propulsion technology focusing on rotor sails. Japan’s Mitsui O.S.K. Lines is working on a project to add a hard sail to a coal carrier, while Yara Marine Technologies and BAR Technologies are working on a project to install solid sails aboard Cargill bulk carriers.