UFC 4-159-03
3 October 2005
Six degree-of-freedom quasi-static analyses using the program AQWA LIBRIUM are
performed on various LPD-17 mooring configurations to determine safe mooring limits
as follows:
Figure 8-19 shows a sample Standard Mooring (Mooring Service Type IIa)
for the ship broadside to a current pushing the ship off the pier. In this example the
water depth is 45.3 feet for a ship draft to water depth ratio of T/d = 0.5. The maximum
safe wind speed for various current speeds is illustrated with a factor of safety of 3.0 or
higher on all mooring lines.
Figure 8-20 shows a sample Storm Mooring (Mooring Service Type IIb) for
the ship broadside to a current pushing the ship off the pier. For the case of a major
approaching storm the lines are run across the pier to the bollards on the opposite side
to significantly improve mooring efficiency. In this example the water depth is 30.2 feet
for a ship draft to water depth ratio of T/d = 0.75. The maximum safe wind speed for
various current speeds is illustrated with a factor of safety of 3.0 or higher on all mooring
lines.
Figure 8-21 shows a sample Heavy Weather Mooring (Mooring Service
Type III) for the ship broadside to a current pushing the ship off the pier. For the case of
a major approaching storm or hurricane the lines are run across the pier to the bollards
on the opposite side to significantly improve mooring efficiency. Ship's lines are not
adequate for heavy weather mooring. Therefore, double braided polyester lines are
used because they have excellent fatigue resistance and some stretch to help improve
load sharing. In this example the water depth is 40 feet for a ship draft to water depth
ratio of T/d = 0.57. The maximum safe wind speed for various current speeds is
illustrated with a factor of safety of 2.5 or higher on all mooring lines. These dynamic
analyses were performed with the six-degree-of-freedom AQWA DRIFT. Figure 8-22
illustrates LPD-17 mooring at a double-deck pier.
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