UFC 4-159-03
3 October 2005
current and get caught by a sudden storm, such as a thunderstorm. Type III mooring
during repair may provide the greatest potential of risk, because the ship is moored for a
significant time and cannot get underway. There are several U.S. shipyards where
DOD ships can undergo major repairs. The area near Norfolk/Portsmouth, VA has
some of the most extreme design criteria, so ship's hardware design should be based
on conditions derived from this site. Ship mooring hardware environmental design
criteria are given in Table 3-6. During Type IV mooring, the ship is usually aligned with
the current, extra padeyes can be welded to the ship hull for mooring, etc., so special
provisions can be made for long-term storage.
3-2.4
Strength. Moorings should be designed and constructed to safely resist
the nominal loads in load combinations defined herein without exceeding the
appropriate allowable stresses for the mooring components. Normal wear of materials
and inspection methods and frequency need to be considered. Due to the probability of
simultaneous maximum occurrences of variable loads, no reduction factors should be
used.
3-2.5
Serviceability. Moorings should be designed to have adequate stiffness
to limit deflections, vibration, or any other deformations that adversely affect the
intended use and performance of the mooring. At the same time moorings need to be
flexible enough to provide for load sharing, reduce peak dynamic loads and allow for
events, such as tidal changes.
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