UFC 4-159-03
3 October 2005
Table 5-2. Anchor Characteristics
(a) Drag-Embedment Anchors
CHARACTERISTICS
NOTES
Many basic designs and sizes are
NAVMOOR-10 & -15 and stockless of 20 to
available from manufacturers.
30 kips are stocked by NFESC.
Works primarily in one horizontal
Enough scope of chain and/or wire rope
direction.
needs to be provided to minimize uplift
forces, which can pull the anchor out. If a
load is applied to a drag anchor at a
horizontal axis off the centerline of the
anchor, then the anchor may drag and reset.
Flukes should be set for the soil type. Anchor performance depends strongly on
the soil type. Fixing the maximum angle of
the fluke will help ensure optimum
performance. For mooring installations the
flukes should be fixed open and stabilizers
added for stockless anchors to help prevent
overturning.
Adequate sediment required.
Sand layer thickness needs to be
approximately one fluke length and mud
needs to be 3 to 5 fluke lengths thick.
May not work in all seafloor types.
May be unreliable in very hard clay, gravel,
coral, or rock seafloors; and in highly layered
seafloors.
May not work well for sloping
If the seafloor has a slope of more than
seafloors.
several degrees, then the anchor may not
hold reliably in the down-slope direction.
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