Anchoring equipment-Chain locker

The anchoring equipment fitted to the majority of vessels consists of two matched units, offering a degree of redundancy.
These units consists of an anchor, chain (or for smaller vessels wire), a gypsum or chain lifter wheel, brake, lift motor and various chain stopper arrangements.
When not in he use the chain is stowed in a chain locker, systems fitted with wire are stowed on a drum in the same way as winches.

Chain locker

A false bottom is fitted to the chain locker consisting of a perforated plate. This allows water and mud to be removed from the space. The end of the chain is attached to the hull by a quick release mechanism known as the 'bitter end'.
The strength of the 'Bitter End' fixing arrangement for a moderately large vessel is in the region of 6 Н tons, this will not be sufficient to prevent a run away unbraked chain. The arrangement must be easily accessible.
The proof load for the windlass (the load the windlass must withstand without being pulled from the deck) is given by;

6.18 dc² (44 + 0.08dc) [kN]

Where dc is the diameter of the chain metal

This will prove that it is strong enough. It must also be as strong as the braking load on the cable.
The windlass must be capable of pulling the anchor from a depth of 25% of the total cable carried, i.e. 50% of the length of chain on one side
It should be capable of lifting the anchor from 82.5m to 27.5m at 9m/min.

Motive force

May be steam, electrical, hydraulic or even engine driven although the latter is rare. A gear box arrangement, heavy tooth pitch on final drive, are fitted

Brake

Generally consists of ferodo lined half cylinder steel bands which are joined by a pivot point at the rear. The bands are closed and opened by the action of a threaded brake wheel spindle acting on the fixings at the front of the band ends