122 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
by tapping with a hammer to hear if they give out a clear ring. It is
desirable to occasionally replace the two or three lengths nest the
anchor with two or three lengths from the bottom of the locker as all
chain gets fatigued and brittle when lying idle. This also gives an
opportunity of cleaning out the locker. When dirty cable is being hove
up from a muddy bottom it should be hosed down as it enters the hawse-
pipe. It may be remarked here that at each survey the masts, spars,
rigging and general deck equipment are inspected, including hatch covers
and supports, tarpaulins, cleats and battens, ventilator coamings and
covers.
The Anchors and Chain Cables Act insists on rigorous tests being
applied to mooring cables, the responsibility for their efficiency, in the
first instance, being on the maker. The chain is made in 15 fathom
lengths with three additional experimental links; the sample links and
the length of cable must each be stamped with a distinctive identification
number.
The cable is taken to a testing establishment licensed by the Board
of Trade, and the three links cut out and submitted to the full breaking
strength, but only the proof test, which is about 70 per cent, of the tensile
breaking strength, is applied to the 15 fathoms length. The breaking
load is about 24 D2, D being the size of the cable chain in inches. - After
it has been tested the length of chain is measured for elongation and
each link separately examined by two inspectors for flaws, cracks,
broken or twisted studs, etc. The cable when passed is stamped
with the Board of Trade test marks and a full description of its length,
weight, size of the links and shackles and a record of the tests, makers'
name, ship's name, etc., are recorded on the Cable Certificate which
must be carried on board the ship and produced when required.
A drop test is applied to anchors. The ancnor is raised so that its
lowest part is at a height of 12 feet and then dropped on a steel or iron
slab. It is dropped side on, and then end on, and if this percussive test
is satisfactory the anchor is then slung up and hammered all over with
a 7 Ib. sledge hammer to see if it gives a clear ring. This test is to
ensure that there are no flaws in the casting and that .none have been
developed by the drop tests.
'The anchor when passed at a Lloyds Proving House licensed by
the Board of Trade is stamped with the Identification Mark of the
Proving House, the Certificate Number, the Number of the Tensile
Machine; Year Licence was granted; Proof Strain.