The Fathom-CTech ‘Tech of the Month’ is Norsepower’s Rotor Sail Solution.
Norsepower’s Rotor Sail Solution uses wind propulsion to reduce emissions, save fuel, and enhance ship efficiency while maintaining speed and voyage time.
The auxiliary wind propulsion system is based on a technology that was originally invented by Finnish engineer Sigurd Savonius and was later demonstrated by Anton Flettner in an Atlantic crossing that took place in 1926.
The technology operates on a principle known as the Magnus effect. The Rotor Sail accelerates incoming air flow on one side of the Rotor Sail and restricts the air flow on the opposite side of the Sail. This creates a pressure difference that is perpendicular to the direction of the wind flow and facilitates a lift force. As this lift is created in a much smaller area, the efficiency of the solution is higher than a conventional sail.
The thrust created by the Magnus effect can be used to propel ships by placing a cylinder on the main deck and rotating it around its main vertical axis. The auxiliary grid in the ship then powers the electric drive system to rotate the Rotor Sail.
The technology was installed on Bore’s Ro-Ro carrier MS Estraden for sea trials, approved by Lloyd’s Register. These sea trials, verified by NAPA and supported by VTT Technical Research Centre of Finland, confirmed fuel savings of 2.6% using a single small Rotor Sail on a route in the North Sea.
Based on the trials, Norsepower and Bore believe that a full system on MS Estraden with two rotors could deliver 5% efficiency savings on an ongoing basis.
Norsepower forecasts savings of 20% for vessels with multiple, large rotors traveling in favourable wind routes. Up to 30% fuel savings are possible for slow steaming vessels with many rotor sails.
Turnkey delivery cost for a typical Norsepower Rotor Sail installation with three 24-metre Rotor Sails is less than US$2 million. Considering the reductions in fuel costs, Norsepower estimates a payback period of less than 4 years.
The Norsepower Rotor Sail Solution is mainly designed for tankers, bulk carriers, ro-ro vessels and ferries and is applicable to newbuilds and as a retrofit.
Three sizes of Rotor Sails are available – heights of 18, 24, or 30 metres. The number of Rotor Sails required and the exact specifications of the sails are dependent on the size, speed and operating profile of the individual ship.
The technology is very simple and user friendly, requiring no reefing or crew and can be managed from the bridge. The operation and performance of the Rotor Sails can be fully control through a control panel, an automation unit optimises the forward thrust of the Rotor Sails and provides real-time feedback regarding wind speed, direction, ship speed, and course data.
Norsepower Rotor Sail Solution is delivered as a full-service solution that includes both delivery and maintenance of the hardware and software components.
