WIND FORCE
 There is an impact of 3 main forces on the yacht.
1.) Wind force
2.) Kinetic energy (caused by movement of the yacht)
3.) Energy caused by current & waves
Wind pressure results in a major force impact on cleats and ropes. It can be calculated with the following mathematical formula.
F = 0,5 * p * Cw * A * V²
F … wind force [ kg ]
p … air density [ kg/m³ ]
(e.g.: p = 1,293 Kg/m³ at 0°C / p = 1,204 kg/m³ at 20 °C)
Cw … air resistance
(e.g.: round plate = 1,11 / square plate = 1,50 / convex bowl = 0,34 )
A … area exposed to wind [ m² ]
V … wind speed [ m/s ]
Example 40' yacht:
Area exposed to wind: 15 m²
Weight: 10 tons
Air density p: 1,204 kg/m³
Air resistance Cw: 0,75
Wind speed | wind force | | | [Km/h] | [m/s] | kg/m² | kg | | | 10 | 2,8 | 0,4 | 5,3 | | Light air, wind force 1 (bf) | 30 | 8,3 | 3,2 | 47,9 | | Moderate breeze, wind force 4 (bf) | 50 | 13,9 | 8,9 | 133,2 | | Strong breeze, wind force 6 (bf) | 75 | 20,8 | 20,0 | 299,6 | | Fresh gale, wind force 8 (bf) | 100 | 27,8 | 35,5 | 532,7 | | Whole gale/storm, wind force 10 (bf) | 125 | 34,7 | 55,5 | 832,3 | | Hurricane 1/2, wind force 12 (bf) | 150 | 41,7 | 79,9 | 1.198,6 | | Hurricane 3 | 200 | 55,6 | 142,1 | 2.130,8 | | Hurricane 4 | Force on 1m² 
|  Force on 40' yacht | |
