UFC 4-159-03
3 October 2005
Table 3-7. Minimum Quasi-Static Factors of Safety
NOTES
COMPONENT
MINIMUM
FACTOR OF
SAFETY
Stockless & balanced
1.5
For ultimate anchoring system holding capacity;
fluke anchors
use 1.0 for ship's anchoring*
High efficiency drag
2.0
For ultimate anchoring system holding capacity
anchors
use 1.0 for ship's anchoring*
Fixed anchors (piles &
3.0
For ultimate anchoring system holding capacity*
plates)
Deadweight anchors
-
Use carefully (see Naval Civil Engineering
Laboratory (NCEL) Handbook for Marine
Geotechnical Engineering, 1985)
3.0
For relatively straight lengths.
Chain
4.0
For chain around bends.
These factors of safety are for the new chain
break strength.
Wire rope
3.0
For the new wire rope break strength.
Synthetic line**
3.0
For new line break strength.
Ship bitts
***
Use American Institute of Steel Construction
(AISC) code.
Pier bollards
***
Use AISC & other applicable codes.
*It is recommended that anchors be pull tested.
**Reduce effective strength of wet nylon line by 15 percent.
*** For mooring fittings take 3 parts of the largest size of line used on the fitting; apply a
load of: 3.0*(minimum line break strength)*1.3 to determine actual stresses, σact.; design
fittings so (σact./ σallow.)<1.0, where σallow. is the allowable stress from AISC and other
applicable codes.
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