ERDC/CHL CHETN- IX-7
December 2001
Table 2
Transit Parameters Barbers Point Harbor, HI
Vessel
Inbound Runs
Outbound Runs
Draft, m
Draft, m
Name
Code Date
Time
Tide, m
Load Bow
Date
Time
Tide, m
Load Bow
Stern
Stern
A
21
6:30
+0.2
F
8.92
10.12
25
6:30
+0.0
L
4.36
6.85
Atoyac
CAH
18
9:00
+0.0
L
4.47
7.54
19
18:30
+0.6
F
7.39
8.96
Carla A. Hills
I
5
11:00
+0.0
F
7.90
10.10
9
9:00
+0.2
L
7.40
9.50
Igrim
PC
14
12:00
+0.2
F
9.70
9.70
16
12:00
+0.7
L
5.55
7.70
Port Catherine
WU
20
6:30
+0.2
L
4.29
6.43
30
10:00
+0.2
F
10.75
10.92
World Utility
Notes:
1. Date is relative to May 1999
2. Time is Hawaii Standard Time (HST)
3. F = Full load (MAX draft), L = Light load (MIN draft)
Three GPS sensors were positioned on each vessel, two on either side of the bridge and one at
the bow of these vessels. The bow sensor was located several feet from the bow on the
longitudinal center line and the port and starboard sensors were located on both sides of the
bridge wings, approximately 30.5 m (100 ft) forward of the stern. A land-based GPS receiver
was used in this dual-frequency, DGPS system to insure cm-level accuracy of the measurements.
All GPS data were referenced to a static ship survey. Engine speed and rudder commands were
also recorded.
The six DOF motions of a moving
ship are the three translations of
surge, sway, heave, and the three
rotations of roll, pitch, and yaw
(Figure 3). A ship typically rotates
about the center of gravity (CG),
located on the longitudinal center line
approximately amidships. The wave-
induced portion of the hUKC is a
function of the vertical motions from
heave, pitch, and roll.
The vertical motions from the three
GPS sensors were averaged to obtain
Figure 3. The 6-deg of freedom ship motions
the net vertical excursion for each
ship transit. The location of the average of the three sensors is approximately equal to the CG.
A digital filter was applied to the data with a cutoff of 30 sec to separate low and high frequency
to the wave-induced vertical motions. Measured squat was less than 1 ft (0.30 m), and very
transient due to the short channel and varying ship speeds.
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