A boat anchor is device having a wooden or metal frame and is used to hold vessels, boats and ships in place. Anchors gain holding power by "hooking" into the seabed. Anchors can be temporary or permanent depending upon the use. Vessels usually have one or more temporary anchors of varying design and weight. The modern anchor consists of a shank (the stem) a stock (the crosspiece at the top of the shank , a crown (the bottom portion), and arms attached near the base of the shank at a right angle to the stock and curving upwards.
Some facts about boat Anchors
1. Modern anchors are lighter and the best holding anchors are actually the lightest, contrary to what most think. Anchor design has more effect on holding power than weight.
2. Most anchors are made of steel for its strength. However high-tensile aluminum-magnesium alloys are also used now as they have double the strength of steel.
3. The performance of an anchor depends on the design and the metal of the anchor. So two anchors that may look alike may work differently because of the difference in the manufacturing and the metal alloys used to make it.
4. Anchors are selected according to the type and weight of the boat. For example canal boat designs would require an anchor such as the CQR or Danforth about 15Kg. A canal boat design is such that the boat is long with a short beam and there will be few waves on the Weaver. A fortress can also be used as it works just like the Danforth, but is made of aluminum hence lighter in weight.
5. Different anchors have different holding power. Danforth or sand type, and the CQR or plough type are the two types of anchors that have the most holding power. The sand type gives very decent holding power for its weight but its disadvantage is that it does not penetrate well through weeded bottoms.
The length of anchor line relative to the distance from the boat's deck to the bottom of the sea is called scope. Adequate scope also doubles the holding power of the anchor.
6. Anchoring doesn't depend on the anchor alone. Much depends on the chain, shackles and deck gear. One needs to have a little bit of anchoring skills too.
The history of anchors dates back to thousands of years. Before the invention of anchors ,thousands of commercial and war ships have been lost due to the absence of ground tackle, and has resulted in the loss of many lives and cargo.
Primitive man's first anchor was a crude stone tied to a rope. These anchors depended on weight alone for holding rather than hooking or burying compared to modern anchors. To avoid dragging, wooden crooks, cages or iron hooks were added which resulted in a better increase in holding power. The oldest record of the common anchor was found on the greek and syrian coins of 750 BC .These anchors had two hooked arms and an upward shank.