intended route, or determining how frequently the
. Wind speed is entered in whole knots. The
superstructure ice should be cleared.
algorithm considers winds from 22 to 71 kt by the
LIMITATIONS AND
ASSUMPTIONS
The restrictions as well as
for granted in using the SHIP
follows:
following categories:
—
Beaufort Force 6 and 7 (winds 22 to 33 kt)
—
Beaufort Force 8
(winds 34 to 40 kt)
the principles taken
—
Beaufort Force 9 and 10 (winds 41 to 56 kt)
ICE program are as
. The methods described here are best applied to
smaller ships. Ship’s characteristics, such as freeboard,
waterline length, hull response, and ship’s course and
speed are not considered.
. Information relating to ice accretion thresholds
is not available and must be developed independently
by each user.
. Air temperature is entered in whole degrees
(Celsius). For temperatures <-21°C, the SHIP ICE
model assumes a constant accretion rate based on
-21°C. The algorithm considers temperatures from
-2°C to -21°C.
. Sea temperature is entered in whole degrees
Celsius. The algorithm considers temperatures from
— Beaufort Force 11 and 12 (winds 57 to 71 kt)
l If the air temperature is *2°C, then the ice
accretion is considered to be 0.
. If the wind is <22 kt (BF 6) and the temperature
is <-2°C, then the ice accretion is considered to be 1.5
cm per day.
FUNCTIONAL DESCRIPTION
The SHIP ICE program determines the ice accretion
rates from look-up tables based on the wind category.
For each category, there is an ice accretion matrix with
an accretion rate for each combination of air-sea
temperature (where the air temperatures are between
-2°C and -21°C, and sea temperatures between
10 and -2°C.) Figure 7-5 shows an example of a SHIP
10°C to -2°C.
ICE ACCRETION program.
Figure 7-5.-Examp1e output of the SHIP ICE program.
7-13
