WHITE PAPER - JONES ACT SHIPPING CASE STUDIES: THE FEASIBILITY OF

3 In the UMAS report, there is a caveat regarding the accuracy of JAF numbers, given the scarcity of data on the four requirements for the U. [...] The lift, drag, and power coefficients for the rotor sail follow from the parametric model of Tillig and Ringsberg (2020), based on the rotor sail spin ratio of three, width/height aspect ratio of six, and the respective power input coefficient. [...] Because the wind varies between the surface and the upper reaches of the chosen WAPS elements (30–40 meters above the water surface), we calculated the average wind vectors (true and apparent) in 6-meter vertical increments using the modeled vertical wind profile (Tillig & Ringsberg, 2020). [...] We assumed that the resulting lift and drag forces act at the vessel’s center of mass; the net force acting on the vessel is the difference between lift and drag components in the longitudinal direction. [...] Energy savings for the Badger as a percentage of total fuel costs was about 5 times greater than for oceangoing vessels; the median relative energy saved ranged from 1.8% –4.6% for the rotor sail and 1.3%–2.4% for the wing sail on the Badger, whereas the maximum values were 13.8%–25.2% for the rotor sail and 5.3%–11.0% for the wing sail.