A ship cannot anchor where the water is too deep. It is not just a question
of whether the cable is long enough to reach the bottom; it is important to
remember that the anchor is designed:
- To hook firmly into the sea-bed when the cable is pulling straight along
the ground from the anchor;
- To break out of the ground easily when the cable is pulling from
above.
The anchor will hold only so long as the part of the cable nearest to
it is lying along the bottom, exerting a horizontal pull. The more cable a ship
has out, the less likely she is to drag. The amount of cable used by a ship when
anchoring is normally at least four times the depth of
water.
Cable construction varies from chain, in the case of ships, down to cordage
in the case of small boats. Chain cable is normally made of forged steel or
wrought iron. In all chain cable except the smallest, the links are studded to
prevent kinking. The size of cable is measured by the diameter of the metal
forming a link.
Cable is supplied in lengths of a shackle, which is 27.5
metres long. In HM Ships, shackles of cable are joined by means of joining
shackles. The anchor is secured to the outboard end of the cable by means of an
anchor shackle.
Information used form the Woking Sea Cadets homepage.
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