(6) Mooring forces.

(a) Design of any of these systems requires that the primary hydrodynamic loads on the vessel caused

by the wind, currents, and waves be determined, usually on a probabilistic basis. Other loads that may be

important in certain situations are ice forces and forces induced by passing vessels. The appropriate forces

are employed in a dynamic analysis of the mooring system to determine expected loads in the mooring lines

and on the fender systems. This analysis can be done by a physical model study or by a computer simulation

of the system dynamics equations (see Bruun (1989) and Gaythwaite (1990)). Detailed discussions of the

primary vessel mooring forces, those caused by the wind, currents, and waves, can be found in Tsinker

(1986), Bruun (1989), and Gaythwaite (1990).

(b) The wind load is determined from the usual drag equation

1

2

ρa CD A V10

(II-7-31)

2

where *F*w is the drag force due to the wind, ρa is the air density, *C*D is a drag coefficient, *A *is the projected area

of the vessel above the waterline, and *V*10 is the wind speed at the standard elevation of 10 m above the

water's surface.

Harbor Hydrodynamics

II-7-67

Integrated Publishing, Inc. |