(11)

EQUATION:

deepwater current force drag coefficient for T/d ≈ 0.0;

where

CO

=

this deepwater drag coefficient is estimated from:

C 0 =0.22 * χ

(12)

EQUATION:

where χ is a dimensionless ship parameter calculated as:

χ =*L*wL 2 * *A*m / ( *B ***V *)

EQUATION:

(13)

where

area of the ship at midsection (m2)

the waterline) (m), and

(which can be found by taking the

displacement of the vessel divided

by the unit weight of water, given

in Table 4-1).

C1 = shallow water current force drag coefficient

where T/d = 1.0; for currents of 1.5 m/s

(2.9 knots or 4.9 ft/sec) or less; **C**1 = 3.2 is recommended

T = average vessel draft (m)

= water depth (m)

d

K = dimensionless exponent; laboratory data from

ship models shows:

K=2

Wide range of ship and barge tests; most all

of the physical model data available can be

fit with this coefficient, including submarines.

K=3

From a small number of tests on a fixed

cargo ship and for a small number of tests

on an old aircraft carrier, CVE-55

K=3

From a small number of tests on an old

submarine hull, SS-212

85

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