28.1.1.1. Example 1#
Example (1) Calculation of a force-excursion characteristic with Fairlead attachment 200 m above seabed. Full chain line:
Studless chain Vicinay R4S 147 mm, Breakload 18852 kN, weight 376 kg/m, EA ~ 1850 MN, length 600 m
Example shows: Non-linear line behavior High forces (full chain) With larger excursions high tensions
What is the stiffness?
Stiffness at pretension of 1200 kN equals ~ 15 kN/m
Using example (1) In Multi-line mooring systems, the force-excursion characteristics of the single lines are combined in a total system and are dependent on the pretension in each line.
The resulting stiffness is (refer curve): Kmooring = 600 / 20 = 30 kN/m