Abstract

LAMBRECHT, M.K.; KLINTWORTH, J.W.; JORDAAN, M.G.  and  BUNT, E.A.. Model investigation of aerofoil sails as auxiliary ship propulsion devices. R&D j. (Matieland, Online) [online]. 1994, vol.10, pp.66-84. ISSN 2309-8988.

In recent years, one aspect of the resurgence of interest in saving fossil fuel has been a proposal to use aerofoil sails as an auxiliary form of ship propulsion. To examine the possible effect on running costs of the use of such sails, a simplified model investigation, based on the configuration employed by a Japanese cargo vessel, the 'Shin Aitoku Maru', was undertaken, using models of a RINA Standard Tanker YB fitted with two vertically pivotted NACA 63₃ - 018 aerofoil section sails on the foredeck. The tests involved basically (a) hydrodynamic testing of a 1:100 scale model ship hull in a towing basin; (b) aerodynamic testing (with and without sails) of a 1:300 above-waterline ship model in a low speed wind tunnel; followed by (c) supplementary towing basin testing of a 1:300 ship model (using the same sails), with a fan mounted on the towing carriage to simulate the effects of wind veering from 0° - 180° to the forward direction of travel. The combined results were scaled up for 'standard' (prototype) conditions of a required ship-speed of 11.7 knots, operating in a true wind speed of 13.25 knots (using wind data for a well-used shipping route) to give a polar diagram of expected fuel savings as a function of incidence and angle to the true wind (between 0° and 180°). A maximum saving of about 10% for a true wind direction of 90° was predicted - which is well below the claim for the Japanese vessel that the sails can provide up to 50% of the power required to travel at 12 knots.

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