anchor

An anchor is a device, normally made of metal, used to connect a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ancora, which itself comes from Greek.

Anchors can either be temporary or permanent. Permanent anchors are used in the creation of a mooring [系jì泊], 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.

A sea anchor is a drogue [锥形物], not in contact with the seabed, used to control a drifting vessel.

Anchors achieve holding power either by "hooking" into the seabed, via sheer mass [全靠质量], or a combination of the two. The vessel is attached to the anchor by the rode (commonly called the anchor cable or anchor chain in larger vessels), which is made of chain, cable, rope, or a combination of these.

The ratio of the length of rode to the water depth is known as the scope; generally, the rode should be between 5 and 10 times the depth of the seabed, giving a scope of 5:1 or 10:1; the larger the number, the shallower the angle is between the cable and the seafloor, and the less upwards force is acting on the anchor.

辽宁舰重约5万吨。每个锚重约20吨，加上450米长的锚链共计108吨。辽宁舰使用双锚。

HTML里的<a href="http://www.cnblogs.com/">，a是anchor的缩写, href是hypertext(超文本) reference的缩写。Hypertext is a software system that links topics on the screen to related information and graphics, which are typically accessed by a point-and-click method.

六级/考研单词: anchor, norm, vessel, drift, derive, perpetual, seldom, sheer, shallow, upward, hardware