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 aerodynamics, the aspect ratio of a sail is the ratio of its length to its breadth (chord). A high aspect ratio indicates a long, narrow sail, whereas a low aspect ratio indicates a short, wide sail. For most sails, the length of the chord is not a constant but varies along the wing, so the aspect ratio "AR" is defined as the square of the sail height "b" divided by the area "A" of the sail planform: Aspect ratio and planform can be used to predict the aerodynamic performance of a sail. For a given sail area, the aspect ratio,