4-5.2

force is defined as that component of force parallel to the centerline of the vessel. This

force is determined for streamlined ship-shaped vessels from the following equation

(Naval Civil Engineering Laboratory (NCEL), TN-1634, *STATMOOR A Single-Point*

(15)

EQUATION:

where

total longitudinal current load (newtons)

longitudinal current load due to

form drag (newtons)

longitudinal current load due to skin friction (newtons)

longitudinal current load due to propeller drag (newtons)

The three elements of the general longitudinal current load equation, *F*xFORM , *F*xFRICTION ,

and FxPROP are described below:

longitudinal current load due to form drag

1

ρw Vc2 B T Cxcb cos(θc )

EQUATION:

(16)

2

where

ρw

mass density of water, from Table 4-1

=

Vc = current speed (m/s)

B = maximum vessel width at the

waterline(m)

T = average vessel draft (m)

Cxcb = longitudinal current form drag coefficient = 0.1

θc = current angle (degrees)

longitudinal current load due to skin friction

89