FORCES ON THE CLEATS
 Find some convincing calculation in the download section
We would like to illustrate forces on the cleats comparing 2 different docking systems
1.) Conventional docking practice: 2 diagonal stern lines & mooring line
2.) Docking system: DualDocker & securing lines.
Example 40' yacht
Area exposed to wind: 15 m²
Weight: 10 tons
Air density p: 1,204 kg/m³
Air resitance Cw: 0,75
Water density p: 998,0 kg/m³
Water resistance Cw: 0,20
1.) Conventional docking practice: 2 diagonal stern lines & mooring line
Wind | Kinetic energy | Current | | Wind speed | Wind force | Moving speed | Kinetic energy | Braking distance | Braking force | Current | Flow force | Angle 60° -factor | Force on cleat | [km/h] | [kg] | [m/s] | [Joule] | [m] | [kg] | [km/h] | [kg] | [kg] | 10 | 5 | 0,01 | 5 | 0,03 | 38 | 1 | 6 | 1,15 | 57 | 30 | 48 | 0,02 | 20 | 0,05 | 76 | 2 | 25 | 1,15 | 171 | 50 | 133 | 0,1 | 491 | 0,26 | 380 | 4 | 101 | 1,15 | 705 | 75 | 300 | 0,2 | 1.962 | 0,53 | 759 | 6 | 226 | 1,15 | 1.478 | 100 | 533 | 0,3 | 4.415 | 0,79 | 1.138 | 8 | 402 | 1,15 | 2.384 | 125 | 832 | 0,4 | 7.848 | 1,05 | 1.518 | 10 | 628 | 1,15 | 3.425 | 150 | 1.199 | 0,5 | 12.263 | 1,32 | 1.897 | 12 | 904 | 1,15 | 4.600 | 200 | 2.131 | 0,7 | 24.035 | 1,84 | 2.656 | 15 | 1.413 | 1,15 | 7.130 |
2.) Docking system: DualDocker & securing lines
Wind | Kinetic energy | Current | | | Wind speed | Wind force | Moving speed | Kinetic energy | Braking distance | Braking force | Current | Flow force | Angle factor | Force on cleat | [km/h] | [kg] | [m/s] | [Joule] | [m] | [kg] | [km/h] | [kg] | [kg] | 10 | 5 | 0
| 0
| 0,00 | 0
| 1 | 6 | 1,00 | 11 | 30 | 48 | 0,005 | 1 | 0,01 | 19 | 2 | 25 | 1,00 | 92 | 50 | 133 | 0,01 | 5 | 0,03 | 38 | 4 | 101 | 1,00 | 271 | 75 | 300 | 0,015 | 11 | 0,04 | 57 | 6 | 226 | 1,00 | 583 | 100 | 533 | 0,02 | 20 | 0,05 | 76 | 8 | 402 | 1,00 | 1.011 | 125 | 832 | 0,03 | 44 | 0,08 | 114 | 10 | 628 | 1,00 | 1.574 | 150 | 1.199 | 0,04 | 78 | 0,11 | 152 | 12 | 904 | 1,00 | 2.255 | 200 | 2.131 | 0,06 | 177 | 0,16 | 228 | 15 | 1.413 | 1,00 | 3.772 |
Force impact caused by wind and current are the same no matter which docking system is used.
The reason for significantly lower forces on the cleats when using the 'DualDocker & securing lines' system is based on the fact that kinetic energy is minimised from the start. |
