VIII. Retell the text “Bow.” unit 23. Anchor

I. Read and translate the following text:

Fig. 26. A stocked ship's anchor. a. Shank b. Crown c. Arm d. Fluke e. Point f. & g. Eye and Ring h. Stock i. Fisherman's bend

An anchor is an object, often made out of metal that is used to attach a ship to the bottom of a body of water at a specific point. There are two primary classes of anchors—temporary and permanent. A permanent anchor is often called a mooring, and is rarely moved; it is quite possible the vessel cannot hoist it aboard but must hire a service to move or maintain it. A temporary anchor is usually carried by the vessel, and hoisted aboard whenever the vessel is in motion, hence the term "under weigh"; it is what most non-sailors mean when they refer to an anchor. A sea anchor is a related device used when the water depth makes using a mooring or temporary anchor impractical. The hole through which an anchor rope passes is known as a hawse pipe.

An anchor works by resisting the movement force of the vessel which is attached to it. There are two primary ways to do this — via sheer mass, and by "hooking" into the seabed. It may seem logical to think wind and currents are the largest forces an anchor must overcome, but actually the vertical movement of waves develops the largest loads, and modern anchors are designed to use a combination of technique and shape to resist all these forces.

The earliest anchors were probably rocks and many rock anchors have been found dating from at least the Bronze Age. Many modern moorings still rely on a large rock as the primary element of their design.

A simple anchor using a pair of wood arms under a rock mass is a primitive anchor which is still in use today. The wood arms are pointed to penetrate the bottom, and the mass will overcome normal movement forces. Together they comprise what may have been the first successful attempts to hook into the seabed and use the strength there to prevent a vessel from moving.

a. Design of temporary anchors

A modern temporary anchor usually consists of a central bar called the shank, and an armature with some form of flat surface (fluke or palm) to grip the bottom and a point to assist penetration of the bottom; the position at which the armature is attached to the shank is called the crown, and the shank is usually fitted with a ring or shackle to attach it to the cable. There are many variations and additions to these basic elements—for example, the whole class of anchors which include a stock such as the fisherman and fluke anchors.

b. Designs of permanent anchors

These are used where the vessel is permanently sited, for example in the case of light vessels or channel marker buoys. The anchor needs to hold the vessel in all weathers, including the most severe storm, but only occasionally, or never, needs to be lifted, only for example if the vessel is to be towed into port for maintenance. An alternative to using an anchor under these circumstances may be to use a pile driven into the seabed.

Permanent anchors come in a wide range of types and have no standard form. A slab of rock with an iron staple in it to attach a chain to serves very well, as does a Chevy long-block motor. Modern moorings may be anchored by sand screws which look and act very much like over-sized screws drilled into the seabed, or by barbed metal beams pounded in (or even driven in with explosives) like pilings, or a variety of other non-mass means of getting a grip on the bottom. One method of building a mooring is to use three or more temporary anchors laid out with short lengths of chain attached to a swivel, so no matter which direction the vessel moves one or more anchors will be aligned to resist the force.