Robert Dane will be opening speaker at the 3rd International Symposium on Marine Propulsors (SMP) in May.
The symposium is dedicated to the design and hydrodynamics of all types of marine propulsors. SMP provides a forum to present state-of-the-art research and studies on existing marine propulsors as well as a platform for introduction of new types of propulsors. Environmental issues are addressed through topics on green propulsion and the hydrodynamic aspects of renewable energy devices.
The working title and abstract of Robert Dane’s speech is:
Wind Energy Assistance for Vessels Travelling at 13.6 knots (7m/s) on any Global Shipping Route by Retrofitting Opening Wingsails
Abstract:
For centuries ships navigated the oceans using wind energy harnessed by sails. In the last 200 years sails have been replaced first by steam and then diesel engines.
Megatrends in modern bulk and tank shipping of increased cost of fuel and increased regulations eg Energy Efficiency Design Index (EEDI) and Ship Energy Efficiency Management Plan (SEEMP) mean ship owners, operators and classification societies are looking for energy efficient and energy saving designs and technologies.
This paper takes NASA satellite/buoy/ship cross calibrated ocean wind data, both direction and strength, 10 m above sea level in 14nm segments over 22 years from 1st July 1987 to 30th Dec 2010 available under the Freedom of Information Act. This data is formatted into a look-up table so any shipping route in the world can be analysed. The port of origin and the port of destination and waypoints are put into the algorithm and then with the vessel travelling at 13.6 knots (7m/s) the apparent wind direction and strength for each 14nm segment is calculated. The concept of ‘motor – sailing’ ie the sum of the vectors of true wind and relative wind created by the vessel, is described.
For any route, the voyage is run starting on the 1st of July 1987. The lift for each segment is calculated, assuming 3000sqm of wing sail for a panamax and 4800sqm of wing sail for capsize, to give the amount of reduction of the ship’s main engine to maintain 13.6 knots ship speed. Wing sails and the development of a new opening rigid wing sail will be described.
The voyage is then run on the 2 July 1987 and then the third of July 1987 and repeated by the program 8500 times to the 30th Dec 2010 – giving an accurate historical mean of the amount of energy that saved by using sail assist. This average over 22.5 years is then converted to fuel savings for that route based on modern propeller efficiencies and typical ship engine fuel consumption of 170 g/kWh and converted to cost savings using todays fuel price.
Summary of Results:
Without altering the primary propulsion system of a modern tanker of bulker, and using (retrofitted) opening wing sails to ‘motor-sail’, ship operators can expect 20% -25% fuel savings on cross-equator shipping routes and 30-40% on same-hemisphere shipping routes. Return on investment at today’s fuel price is estimated to be 1-2 years.
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