Forces on sails (3 m) = 5-m/s (≈10-knot) wind at 3 m above the water would be approximately "V" (15 m) = 6 m/s (≈12 knots) at 15 m above the water. In hurricane-force winds with "V" (3 m) = 40-m/s (≈78 knots) the speed at 15 m would be "V" (15 m) = 49 m/s (≈95 knots) with "p" = 0.128. This suggests that sails that reach higher above the surface can be subject to stronger wind forces that move the centre of effort ("CE" ) higher above the surface and increase the heeling moment. Additionally, apparent wind direction moves aft with
Forces on sails keels, centerboards, and other underwater foils, including rudders, that provide lift in the lateral direction, to provide hydrodynamic lateral force (P) to offset the lateral force component acting on the sail (F) and minimize leeway. Such foils provide hydrodynamic lift and, for keels, ballast to offset heeling. They incorporate a wide variety of design considerations. The forces on sails that contribute to torque and cause rotation with respect to the boat's longitudinal (fore and aft), horizontal (abeam) and vertical (aloft) rotational axes result in: roll (e.g. heeling). pitch (e.g. pitch-poling), and yaw (e.g. broaching). Heeling, which results from the lateral