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Anchor chain. The component part of the anchor device
The anchor chain is an important element of the anchor device and the entire ship as a whole. The first anchor chains appeared two hundred years ago. Now the design of the anchor chain follows the standards and undergoes mechanical tests.
History of the anchor chain
For centuries sailors used hemp ropes to anchor the anchor. Sailing vessels of the middle of the last millennium were kept during the stay by small anchors, and the strength of ropes from hemp was enough. With the development of shipbuilding, sea ships and, consequently, anchors became heavier. To ensure strength, the hemp ropes reached a half-meter in circumference, so you had to use thinner ends to wind ropes in the bollard or refresh the spire drum. In addition, the hemp ropes were rubbed against the anchor crest and cut with ice to compensate for their light weight, it was necessary to weight the anchor rod.
The end of the eighteenth and the beginning of the nineteenth centuries are known for single cases of application of metal anchor chains, which have proved themselves remarkably during both storms and during the ice break on the Thames. The official beginning of the use of the metal chain is 1814.
The Pallada frigate, launched in 1832, is the first ship of the Russian fleet equipped with anchor chains.
Already in 1859, before installing on the British Fleet's ships, the anchor chains began to undergo stretching according to the requirements developed by the Lloyd's Register, and in 1879 - also on the break.
Register of Shipping Requirements
Especially violently, the Russian fleet began to develop in the early twentieth century, and the existing classification of ships ceased to meet the safety requirements. Therefore, in 1913 the national classification society "Russian Register" was formed, which in Soviet history became known as the Register of the USSR, and now - the Russian Maritime Register of Shipping (RS). Its tasks include the measurement and classification of ships and floating structures, the maintenance of their registers, their supervision and technical supervision.
According to the requirements of the Register, sea vessels must have two working stations and one sea anchor reserve. In this case, the length of each chain must be at least two hundred meters, a spare anchor bow is provided. And also two connecting links and the end bracket. Anchor device of the ship provides mechanisms, whose power allows you to choose anchors in no more than half an hour. The elements of the anchor device are subject to the Register's supervision.
Anchor device
The anchor attached to the chain is given or raised using special mechanisms and devices. Anchors, chains, stoppers, devices for recoil of the end of the chain, the haws are all together and constitute the anchor device of the ship. It has two anchors along the sides located in the bow of the ship. A winch with electric or hydraulic drive is installed on the nose. The main part of the winch is an asterisk, on which the chain links are wound. The design of the winch also includes drums, on which the mooring lines are wound.
The chain from the anchor passes through the groove in the board, the anchor hook and the stopper, is wound on the sprocket of the winch and is secured with a free end to the ship in the chain box.
Some ships are equipped with stern anchor devices. Since there is limited space in the stern, a spire is used to lift one or two stern anchors. It is a rotating drum with an asterisk at the bottom, mounted vertically. In motion, it is driven by an electric motor, which can be either in the drum itself or under the deck. A chain is wound on the sprocket. The photo shows the spire device, where 1 is a drum, 2 horizontal sprocket, 3 is an anchor chain.
Locking and fastening elements
Stoppers fasten, prevent spontaneous etching and keep the chain and anchor in the bowl in tension. They can be stationary or portable: chain and deck.
According to the design, the stoppers are screw cams or with a locking link. Eccentric stoppers are installed on small vessels. Chain stops are short bows that are passed through the anchor bracket and are attached to the shoes on the deck with two ends.
Anchor bowls that serve to clean the anchor and anchor chain can be ordinary, welded or cast for transport and fishing vessels; Open in the form of a massive casting with a trough on low-aboard vessels; With a niche in the side plating on passenger ships, ice navigation vessels, allowing to clean the anchor flush with the skin, thereby reducing the risk of its damage.
Armature types and designs
Today there are four types of anchors. With the help of anchor anchors, which are located in the bow, the vessel is held in place. Their maximum weight on aircraft carriers reaches 30 tons. Auxiliary anchors on the stern are intended to prevent the ship from turning around the station. For long-term retention, floating objects, for example buoys or lighthouses, are fixed by "dead" anchors. The deliveries are kept by special vessels, so-called. Vessels of the technical fleet for the extraction of minerals.
For today in the world it is known more than five thousand kinds of anchors. But the sea anchor consists of four main parts. The basis of the whole construction is the spindle. On the spindle, horns with paws are fixed or hinged, which burrow into the ground and keep the ship in place. Perpendicular to the horns and spindle is the rod, which turns the anchor on the bottom after immersion and prevents the horns from lying horizontally. Fastening of the anchor to the rope or anchor chain is provided by a clamp and a ring, which is called a rim.
The main elements of the anchor chain
The main element of the anchor chain is a link that is made from a welded steel welding rod with a cast-iron buttress or cast along with a spacer made of soft rolling steel.
The anchor chain anchors are connected by connecting staples, simple or patented, the most common of which is the Kenter brace. Simple braces are not insured against spontaneous opening. In addition, when used, the end links of the bows are made without buttresses and are larger than the conventional links.
The Kenter's brace is similar to the usual link, only detachable. The two halves of the bracket are connected to the lock and held by a spacer, into which the stud with a lead stopper is inserted at an angle.
The swivel, which protects the anchor chain from twisting during anchorage, is usually a design from the actual swivel, end link and two reinforced links between them.
The reinforced link - with a buttress, smaller in size than the end, but larger than the usual link. The anchor bracket is inserted into the eye of the armature spindle, it also connects to the end link of the swivel with the anchor bracket turned to it by the backrest.
Anchor chain design
Anchor chain, like any, consists of links, but the design is not so simple. The links are assembled into segments of a certain length, which are called intermediate bows. According to the standards of the Russian fleet, the length of the bow is 25 meters, in the British, where the measurement of the length in yards is taken to be 27.43 meters or 30 yards. Bows to the desired length of the chain are assembled and connected to each other by the links of Kenter. This method of assembly makes it easy to remove damaged areas and change the length of the anchor chain if necessary.
The root bow, which is fixed in a chain box, ends on the one hand with an end bracket, and on the other is strengthened with a gum. Zhvakogalsovy bow is a short, one end fixed in a chain box and with a hook at the other end of the chain. The photo shows that you can release the toe of the folding hook. This design allows one person to quickly release the ship from the anchor chain.
Anchor bow (running end) also differs in design from intermediate. It includes a swivel. And the bow ends with a brace, to which the anchor is attached.
The size of the anchor chain
The basic size that determines the thickness and characteristics of the chain is its caliber. Caliber - the diameter of the rod from which the link is made, or the end of the link, depending on the method of its manufacture. Through the caliber, the other dimensions of the links that make up the chain are expressed.
The length of the chain depends on the type of vessel and its dimensions. It should be much larger than the depth of the sea in the parking lot, because, firstly, the weight of the part of the chain lying on the bottom helps the anchor to lie on the bottom and hold it there, and secondly, the force that acts on the anchor when engaged on the bottom, Should be directed not up, but horizontally.
Naval ships usually have anchor chains consisting of 10-13 clusters in a caliber from 80 to 120 mm, which depends on the size of the anchor anchor. If the gauge is more than 15 mm, then the links are made with a buttress - a transverse bridge, which increases the strength of the link by more than 20%.
In addition to special meters, color markings are used on the anchor devices. The number and color (white or red) of the colored links depend on the number of etched meters or bows that make up the chain. The photo shows that a hundred and forty meters of the chain is etched, as on both sides of the red staple of Canter, two links are painted in white. To determine the length of the chain in the dark, the benzene from the soft annealed wire is placed on the buttress of the last before the painted link.
Parameters of the anchor chain
The main parameters of the anchor chain are the caliber, the category of strength, the mechanical stresses on the tear and the theoretical theoretical mass. According to the design parameters, the links of the anchor chain are with buttress and without it.
According to the strength characteristics, which depend on the caliber, material and manufacturing method, the anchor chain can be normal, raised or high strength. Chains can differ and by a way of manufacturing of links and struts.
Compliance with production standards is a prerequisite for the manufacture of anchor chains. For example, chain anchor GOST 228-79 - a product with spacers, which is made of carbon and alloyed steels, has approved mechanical properties, has a degree of strength of three categories and the caliber of the main links with a strut from 11 to 178 mm.
The quality of mechanisms, assemblies and individual parts of anchor devices, including chains, is not only the reliability and safety of the ship, but also a guarantee of safety, and sometimes the lives of people on board.
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