Chain sizing

Each vessel is given an equipment number which is calculated with use of a formula and tkaens into account the vessels size, underwater area and sail area. From this a 'look-up' table may be used to give an appropriate size of cable. The diameter of the chain may be read from this table and differs depending on the grade of steel. This grade of steel varies from U1 ( mild steel), U2 (Special Steel) to U3 (extra special steel).
The size of cable that is to be used is found by the use of a formula which is
Equipment number = D2/3 + 2Bh +A

where
D = Displacement
B = beam
h = Freeboard + height of deckhouses over B/4 wide
A = Transverse area including deckhouses over B/4 wide

Connecting chain and components

To join two sections of chain a 'kenter' (don't quote me on the name) shackle is used. This consists of two half sections and removable bridge all held together by a tapered pin. This arrangement works remarkably well and can be found on all sizes of chain.