PART SEVEN: ANCHORING SYSTEMS
Chain Strength
Designations
For proof coil and BBB chain:- Ultimate breaking strength is the load
at which a chain actually breaks. - Proof load (not “proof coil,” which is a
type of chain) is half the ultimate
breaking load. - Working load limit (WLL) is one-quarter
of the ultimate breaking load.
For high-test chain:- Ultimate breaking strength is the load
at which a chain actually breaks. - Proof load (not “proof coil,” which is a
type of chain) is half the ultimate
breaking load. - Working load limit (WLL) is one-third
of the ultimate breaking load.
Standard Chain Lengths
Chain is traditionally handled in lengths called
a shot(in Europe, a shackle). This is very
roughly related to the old unit of distance
known as a cable. Like most older units of
measure, this varies from country to country.
In the United States, a cable is 120 fathoms
(720 feet), or approximately 0.11 nautical mile.
In the United Kingdom and Germany, a cable is
almost exactly 0.1 nautical mile, or 185 meters.A cable in Holland is 225 meters; in Portugal,
258 meters; and in Russia, 182 meters. (You can
see why the unification of the metric system
was so attractive in Europe.) You would think
that a shot (a shackle) of chain would be^1 / 10 of
a cable, and it can be... well, sort of. But once
again, the old units aren’t consistent. A shot of
chain in the Royal Navy is 12.5 fathoms
(22.86 m), while in the U.S. Navy it is 15 fath-
oms (90 ft. or 27.43 m). In any case, it was tra-
ditional to specify chain in units of shot lengths
of 90 feet (27.43 m) in the United States.
Common modern practice is to sell chain in
leader lengths of either 6 or 20 feet (1.82 or
6 .1 m), or—over 100 feet (30.5 m)—in incre-
ments of 20 feet or 6.1 meters (100 feet,
120 feet, 140 feet, and so on; or 30.5 m, 36.6 m,
42 .7 m).Alternatively, you can purchase en-
tire drums weighing 600 pounds (183 kg) each
or just under. This means that a drum of(^3) / 4 - inch (19.84 mm wire dia.) BBB chain would
contain only 100 feet (30.5 m) of chain, while a
drum of^1 / 4 - inch (7.14 mm wire dia.) BBB
would be 800 feet (244 m), though larger-size
chain is also available in double-size drums
weighing around 1,200 pounds (544 kg).
The best anchor chain can be ordered
with oversize links at either end to facilitate
the attachment of fittings.
Stainless Steel Chain
Manufacturers produce stainless steel chain
from 304 and 316 alloy, but only 316 chain is
TABLE 23-4. ACCO 316 STAINLESS CHAIN SPECIFICATIONS
Lbs.
Trade Trade Standard Standard Inside Inside Inside Inside per Links Links Working Working
Size Size Length in Length inWidth Width Length Length 100 Wgt. per per Load Load
inches mm drum feet drum m inches mm inches mm feet K\kg/m foot meter Limit lbs. Limit kg
(^7) / 32 5.55 800 244 0.40 10.16 0.96 24.38 41.1 0.6 12.46 40.88 1,200 544
(^7) / 32 5.55 1,600 488 0.40 10.16 0.96 24.38 41.1 0.6 12.46 40.88 1,200 544
(^9) / 32 7.14 400 122 0.41 10.41 0.84 21.34 74.9 1.1 14.46 47.44 2,000 907
(^9) / 32 7.14 800 244 0.41 10.41 0.84 21.34 74.9 1.1 14.46 47.44 2,000 907
(^5) / 16 7.94 275 84 0.51 12.95 1.03 26.16 106.7 1.6 11.65 38.22 2,400 1,089
(^5) / 16 7.94 550 168 0.51 12.95 1.03 26.16 106.7 1.6 11.65 38.22 2,400 1,089
(^3) / 8 9.52 200 61 0.59 14.99 1.22 30.99 151.1 2.2 9.84 32.28 3,550 1,611
(^3) / 8 9.52 400 122 0.59 14.99 1.22 30.99 151.1 2.2 9.84 32.28 3,550 1,611
(^1) / 2 12.70 100 30 0.76 19.30 1.59 40.39 265.5 4.0 7.55 24.77 6,500 2,949
(^1) / 2 12.70 200 61 0.76 19.30 1.59 40.39 265.5 4.0 7.55 24.77 6,500 2,949
(^5) / 8 15.87 75 23 0.90 22.86 1.79 45.47 397.8 5.9 6.70 21.98 9,800 4,446
(^5) / 8 15.87 150 46 0.90 22.86 1.79 45.47 397.8 5.9 6.70 21.98 9,800 4,446