Ship Anchor

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A ships anchor is an important component, used to prevent the ship from drifting from its location due to wind and tidal currents. Generally, larger ships having two bow and one stern anchor. Anchors can either be temporary or permanent. Permanent anchors are used in the creation of a mooring, and are rarely moved; a specialist service is normally needed to move or maintain them. Vessels carry one or more temporary anchors, which may be of different designs and weights. The  anchoring  equipment of  a  ship  comprises  the  anchor, anchor  chain  and  the  windlass. Anchor chains are connected to a windlass that can either be of vertical or horizontal design. A vertical windlass is known as a capstan, and we shall describe the operation of the anchor and its components using a capstan.
The capstan has a drive wheel called a gypsy that is notched to suit the forged steel chain links.
The chain is fed from the capstan along the deck of the fo’c’sle head through a pawl and down through a hawsepipe pipe in the deck exiting at the ships bow. From here the chain drops downwards and is connected to the anchor using a shackle whose hardened steel pin passes through a hole drilled in the anchor central shank.
The  modern ship’s anchor  is  called  ‘Stock-less  Bower  anchor  and  is  developed  from  the  primitive  “ stock  Anchor”.


Stockless Anchor
The  modern  Bower  stockless anchor is  in  existence  since  the  days  of  steam  propulsion  and  has  been  developed  to  suit  the  stowing arrangement  in  the  hawse  pipe  of  the  ship  and  with  a  lower  holding  strength  than  the  stock  anchor. The modern  stockless anchor  has  a  holding  strength  of   five  times  its  weight  in  Newtons, whereas  the  ancient or  primitive  stock  anchor  has  a  holding  strength of ten  times  its  weight  in Newtons.  The  reason  for  this  requirement  of  lightness is  that  the  anchor  has  to  be  hauled  quickly (within  30 minutes maximum ),  when  the  weather  deteriorates   during  anchor  stay  and  the  ship  has  to  haul  up  the  anchor  and  proceed  to  sea. A stock  anchor  will take  longer  time  to  haul  up and  therefore  endanger  the  safety  of  the  ship.  In the  worst  condition  it  can  lead  to  capsizing  of  the  ship  especially  if  it  is in  light  condition or  in  the  best  condition  drag  anchor  and  run  aground  ashore. Whereas  in  a sailing ship  the  ship  is  normally  anchored  deep  inside   the  natural  harbour  where the  severity  of  the  sea  condition  does  not  reach. It should  be  understood  that  the    greater  the  holding  force  , the  larger  time  required  to  haul  up  the  anchor.  The  forces acting  on  a  ship riding  anchor  is  described in next blog.

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