The main purpose of the anchor device is to ensure reliable anchorage of the vessel in roadsteads and in the open sea at accessible depths.
In addition, the anchor device is used in a number of other cases, in particular: when mooring a vessel to a pier or another vessel in unfavorable conditions (strong wind, current, etc.).
An anchor placed on the windward side when there is a downwind or current allows you to avoid the vessel from collapsing onto a pier or another vessel: when mooring the vessel stern to the pier or mooring barrels!: for offshore transshipment operations using watercraft.
Dropped anchors when the stern moorings are placed on the pier or barrels limit the mobility of the vessel; to carry out an effective turn of the vessel in a limited free water area (when leaving the harbor, in a narrow area, etc.).
The released anchor allows you to reduce the circulation diameter and perform a safe turn; to quickly dampen inertia and stop the vessel in order to prevent a collision with another vessel; to refloat the vessel.
An anchor set towards greater depths with a steel cable attached to it is removed using a capstan or windlass, which in some cases allows the vessel to be refloated without outside help.
Some elements of the anchor device (hawsees, anchor chains) can be used when towing a vessel. The parts of the anchor device are: anchors, anchor chains, fairleads, chain boxes, devices for attaching anchor chains to the ship's hull, stoppers and mechanisms for releasing and lifting anchors - windlasses or capstans.
The anchor device is located in the bow of the vessel. On icebreakers, tugboats, large-tonnage transport and expedition vessels there is an additional anchor device at the stern, which improves the conditions for handling ships.
According to their purpose, ship anchors are divided into main anchors and auxiliary anchors. The main function of main anchors is to hold the ship in place when the anchor is released. Each vessel must have three main anchors - two in the fairleads and one spare on the deck.
rice. 25 Ice anchor
Auxiliary anchors include: stop anchors are the largest of the auxiliary anchors, having a mass equal to 1/3 of the mass of the anchor anchor. They are used in conjunction with deadlifts to hold the vessel in a certain position relative to the wind when loading and unloading, boarding and disembarking passengers, accepting fuel, etc. in roadsteads, as well as for refloating the vessel; Verps are small ship anchors used along with stop anchors.
The mass of the verp is approximately half the mass of the stop anchor; drecks - small boat anchors weighing from 16 to 45 kg; cats - small three- or four-horned anchors weighing from 5 to 15 kg, used to find sunken objects and catch floating objects; ice anchors are used to hold a ship near an ice field or coastal fast ice; they have a mass of 75-80 kg.
(Fig. 25) is made of T-profile steel. It consists of a spindle 1 and a paw 2, which is placed in an ice crack or in a hollowed out hole; equipped with two brackets. A steel cable is attached to bracket 3, on which the anchor is wound, and to bracket 4 is the short end of a soft steel or vegetable cable, by which the anchor is removed from the hole.
Ship anchors must have characteristics appropriate to their intended purpose. The most important of them is the holding force - the least force that is necessary to apply in the direction of the spindle to tear the anchor off the ground.
Special requirements apply to deadlift anchors. They should give out quickly, pick up the soil well, have great holding force, be easily separated from the ground when lifting, and be conveniently fastened in a traveling manner. At the same time, anchors must be durable, cheap and easy to manufacture.
These requirements have led to the creation of a large number of anchors of various designs. According to the method of picking up soil, they can be divided into two types: anchors with a rod, digging into the ground with one paw; anchors with and without a rod, picking up soil with two paws.
The first type is the Admiralty anchor(Fig. 26, a). It consists of a spindle 1 and two horns 2 with legs 3, cast or forged together with the spindle. The spindle in the lower part has a thickening - a trend, the lower part of which is called the heel 4. In the upper part of the spindle there are two holes: through one of them the anchor bracket 5 is attached to the spindle, and the rod 6 is inserted into the second. The rod has thickenings at the ends that prevent its burying in the ground when the anchor is released.
One end of the rod is bent at a right angle, which allows it to be removed along the spindle when attaching the anchor in a traveling manner. The rod ensures that the anchor quickly picks up the soil. The released anchor rests on the ground with its heel and rests against it with the end of the rod. When the anchor chain is tensioned, the anchor on the ground rotates 90°, due to which the lower horn with its paw is buried in the ground.
simple in design and has great holding force. However, it also has significant disadvantages. First of all, the anchor is inconvenient when releasing and retracting, since it is fixed on the deck in a traveling manner.
In addition, buried in the ground with one paw, the anchor poses a danger to ships in shallow water and poses a threat of entangling its anchor chain behind the second horn rising above the ground. The types of anchors that pick up soil with two arms include the Hall anchor (without a rod) and the Matrosov system anchor (with a rod).
The Hall anchor is primarily used on ships.
The Hall anchor (Fig. 26, b) consists of two main parts - a spindle 1 and a box 2, cast as one piece with two arms 3. A square-section spindle, tapering upward, passes through a hole in the box.
At the lower thickened end of the spindle there is an eye for a roller, the ends of which fit into the sockets located inside the box. Thanks to this, the box with the paws can rotate at an angle of 40-45° when the paws enter the ground. The spindle is held inside the box by two locking pins 5.
The pins only cover the roller 6 inserted into the sockets, do not limit the required angle of rotation of the box with the paws and allow it to rotate in the plane of the paws at an angle of up to 10°. The box has grips 7 (sandboxes), which facilitate the rotation of the paws when entering the ground.
In the upper part there is an eye for the anchor bracket 4, to which the anchor chain is attached.
rice. 26 Ship's anchors
a - Admiralty; b - Hall, c - Matrosova
The released Hall anchor rests on the ground. When the anchor chain is tensioned, the grips rest against the ground and force the paws to bury themselves. The Hall anchor has received wide recognition due to its ease of use.
It gives back quickly, has a fairly large holding force and is conveniently pulled into the hawse when cleaning. Burying into the ground with both paws, the anchor is not dangerous for ships in shallow water, and tangling of the anchor chain in the anchor paws is practically eliminated.
However, if the paws are unevenly buried in the ground, the anchor begins to turn out of the ground when the anchor chain is strongly tensioned, as well as when the direction of the wind or current changes. This drawback was eliminated by the anchor design proposed by the Soviet engineer Matrosov.
rice. 27 Dead Anchors
a, b - reinforced concrete masses; c - “frog”; g - segmental; d - mushroom-shaped;
e - helical; f - one-horned admiralty
Matrosov's anchor (Fig. 26, c) has wide legs 3, located almost close to the spindle 1. Thanks to this, the moment that pulls the anchor out of the ground is reduced. The legs have a rod 2 cast at the same time, displaced upward relative to the axis of rotation of the spindle in the trend of the anchor.
The rod does not interfere with the retraction of the anchor into the hawse; it protects the anchor from tipping over when dragged along the ground, and in soft ground, sinking along with the paws, it increases the holding force. The anchor has a relatively small mass, but at the same time it has a large holding force, equal to 10-20 times the mass of the anchor (depending on the soil).
Anchors Hall, Matrosov, etc. are called retractable, since when fastened in a traveling manner, they are retracted over the entire length of the spindle into special anchor pipes called fairleads.
(Fig. 27) are used to reliably hold in place mooring barrels, lightships, docks, floating workshops and other structures, as well as navigation equipment signs. These are reinforced concrete masses of various geometric shapes or volumetric metal structures that are laid in the ground.
Floating structures are supported by dead anchors with the help of strong chains or cables. The anchor hawse (Fig. 28) is a metal pipe 2 with two sockets, one of which 1 is welded to the deck, and the second 4 is welded to the outer hull plating. On ships that do not have an anchor device at the stern, anchor fairleads are located one on each side only in the bow. So that when attaching the anchor in a stowed manner, its legs do not protrude beyond the side plating, niches 3 are made in the places where the side bells are attached.
Some shipowners, honestly, use 10-12 kg of bricks. In calm conditions, and even with a slight wind, such carelessness is acceptable. But in strong winds, this negligence can have serious consequences. And this is not only a violation of peace, but even the deformation and flooding of the craft, a threat to the lives of people on board.
What characteristics should be taken into account when choosing an anchor?
– Holding force. The higher the holding force, the less bulky the anchor you will have to carry with you. A fairly average indicator for most types of anchors: for every 100 kg of displacement 1 kilogram of anchor weight. In general, any seller should have lists that clearly show calculated data for one or another type of anchor.
– Bottom surface. Of all types of anchors, only The Admiralty anchor does not care about the surface: It can hold on any type of bottom. The rest can work better on one of the soils, and not work at all on the other.
Types of anchors
1. Cat anchor
A fairly common type of anchor, which is used both as a anchor anchor (on small boats) and as an additional one. It is most advisable to use a cat in reservoirs with a sandy bottom or in snags. The paws firmly fix the anchor, hooking it onto the wood, but this can also be a disadvantage: if the hook is too tight, you will have to “donate” the grappling anchor to the snag.
Some shipowners, when making homemade anchors of this type, take into account the factor of the critical load on the metal (often cast iron), which is required to unbend the cat. Thus, by “pressing on the gases,” it is possible to preserve the anchor, even though it is susceptible to deformation. Crampons are not suitable for muddy or rocky bottoms.
It has a high holding force on muddy areas of the bottom. Two wide, oblong and sharp paws, located at a close distance from each other, are capable of piercing into soft areas of the bottom and creating a high-quality fixation of the boat.
The anchor has a somewhat angular shape, does not fold and is heavy, which makes it unprofitable for small displacement vessels.
Reminiscent, in modification, to a Danforth anchor, but differs in higher grip on the bottom, which is provided by the rods. It (grip) remains high even when the boat turns 360", which is especially important in a strong storm. This same quality can be added to the list of disadvantages, since it can be very problematic to remove the anchor from the bottom. Well suited for muddy and finely rocky areas bottom.
The anchor model is similar to the two above. The Hall anchor works like this: having touched the bottom, it lies flat, when the anchor chain stretches it, the lower tide of the paws clings to the ground, forcing the paws to turn and pick up the soil with their blades. In order for the anchor to work reliably, it must be released while moving. The holding force directly depends on the soil. Such an anchor will simply tear out of a loose and heterogeneous bottom. Not suitable for ponds with soft and muddy surfaces.
The Admiralty anchor is increasingly moving to museums, and less and less of it can be found on any vessel, be it a boat, a boat or a yacht. The Admiralty anchor is much inferior in strength to anchors that use two claws for fixation. However, it also has its own, albeit small, advantages. For example, practicality. The Admiralty anchor is suitable for reservoirs with any type of bottom. It holds the boat equally firmly, both on muddy soil, and on rocky, and on a bottom covered with algae.
6. Cobra anchor
It has a high holding force (up to 25-30 kg per kilogram of anchor weight). Thanks to its wide and sharp paw, it not only clings tightly, but when jumping out it is able to quickly catch on to other areas of the bottom. A good model, but it is quite difficult to find a small cobra anchor. It performs well on fine rocky and sandy bottoms.
7. Anchor "Plow"
The design is similar to the cobra anchor, but, unlike the latter, it is not monolithic. It consists of two independent parts, which are fastened in such a way that the “plow” is well kept in the ground even when the craft turns up to 180".
1) Chain
A chain with large links connecting the anchor and the cable can increase the holding force of the anchor. This happens due to the bending of the spindle: the chain bends it as close to the bottom as possible (it becomes more difficult to pull out the anchor in this position). It is necessary that the length of the cable exceeds seven to ten times the distance to the bottom. In this case, the holding force will be fully increased.
2) Float
A prudent step would be to make a foam float, which is attached almost to the edge of the rope, a meter from the knot. Untied or torn out, it will be much easier to find it.
3) Consolidation
The most advantageous point is the one that is as low as possible along the stem. The higher the mount, the greater the leverage and, accordingly, the less force required to turn the craft over or flood the bow. This could very well happen in a storm.
4) Number of anchors
At least two. In addition to the deadlift, there should be, albeit small, a verp (auxiliary anchor). This is the bare minimum that should be on board. It's a good idea to add a storm anchor or a parachute anchor (which is almost weightless) to the list, but many shipowners are very jealous of "extra" items on board.
5) How to save an anchor
The bottom surface can be littered with snags and flooded trees, abandoned crab traps and other debris; the likelihood of being left without an anchor is very high. Therefore, you should not release the anchor without tying the buoy to the trend (the place where the horns connect with the spindle). It is best to have a buoy (called a buoy) with a buoy 10 - 25 m long (depending on the depth at which you anchor) in the vessel's supply at all times. As a last resort, instead of a buoy, you can use any floating object: a wooden block, a piece of foam plastic, etc.
If the anchor is stuck and it is impossible to lift it by the anchor rope without the risk of breaking, just pull the buoy and the anchor will be freed.
It is good to attach a permanent bracket to the trend or make a hole for a buoy.
Sailors have been using anchors since ancient times, because without them no vessel can be anchored. And experts can tell a lot of fascinating things about the history and operating principles of these amazing devices.
The anchor, for all its external simplicity, remains an indispensable device for sailors today. For its reliable operation, correct calculation of mass and design is important. A more or less respectable ship is equipped with anchors that weigh at least a ton, and giant ships can “boast” 30-ton anchors. Moreover, the weight of all the anchors, capable of holding even huge cruise ships or floating aircraft carriers in place, does not reach even a thousandth of the weight of the ship itself!
According to Kirill Plotnikov, a senior lecturer at the Department of Design and Technical Operation of Ships at the Faculty of Shipbuilding and Ocean Engineering at St. Petersburg State Maritime Technical University (SPbSMTU), there is such a concept - the “holding force” of a ship’s anchor device. This is the name for the force that must be applied to the anchor, the spindle (see the picture below) of which is located horizontally, in order to pull it out of the ground.
And this holding force consists of two components:
1) the first is created by interaction with the sea soil of the anchor itself,
2) the second is created by a section of the anchor chain that lies on the ground (for sea vessels, the length of this section is usually at least 25–50 m).
What parts does a typical ship's anchor consist of?
Each type of anchor behaves differently on different soils. When comparing different models, they usually calculate how many times the holding force of the anchor exceeds its own weight (the so-called “holding force coefficient”).
Thus, the first device that ancient sailors used as an anchor was an ordinary stone tied with a rope. It is not surprising that its holding force coefficient was even less than one, that is, the holding force did not exceed the weight of the stone itself. Later, they began to drill holes in it to insert stakes - these were the first primitive anchor horns.
But the ancient Romans already used a design almost familiar to us in appearance: a massive elongated anchor body ended in two reliable pointed horns capable of burying itself in the ground at the bottom. And in order for the anchor to rotate at the desired angle, a rod was also attached to the upper part of its spindle perpendicular to the horns.
By 1852, the most popular all over the world was this elegant-looking “Admiralty” anchor.
But the process of improving these devices was not completed - new ideas and designs appeared every year.
This is what the Hall anchor looks like
The protruding rod made it difficult to raise and retract the anchor, so in this model it was abandoned, and instead the arms of the anchor were made to turn. The Hall anchor clings to the ground with two legs at once.
Cemetery of ancient anchors in Spain
Inventors continue to improve the design of anchors today. At the same time, strong winds and currents still make anchorage impossible. In maritime practice, it is customary to estimate wind speed using a special 12-point scale, says Kirill Plotnikov. It is called the Beaufort scale: here zero points corresponds to complete calm, and 12 points to a hurricane. Most ships can be anchored in winds up to force 6-7.
Of course, the latest holding systems have been developed for modern ships: for example, dynamic positioning systems based on satellite navigation, etc. But a complete abandonment of the use of good old anchors will have to wait a very, very long time!
Based on materials:
A fishing boat, regardless of the size or materials from which it is made, needs a device that fixes its position on the water in a certain place, in other words, an anchor.
Currently, there are about two thousand different anchor designs in the world, among which there are those that are specially designed for small boats and boats.
The most popular and in demand for small vessels are two types of anchors: ordinary mushroom-shaped and “cat” anchors. Both types, in general, are suitable for use on an inflatable boat, but the “cat” must be purchased with a folding one in order to minimize the likelihood of damage to the boat hull by its splayed legs and to reduce the space occupied by this anchor, which is already not a lot on an inflatable boat.
Basic requirement for an anchor- this is the reliable securing of the vessel in place when exposed to waves, wind or current. Therefore, the main characteristic of any type of anchor is its holding force, one of the main parameters of which is the mass of the anchor. The weight of the anchor is either calculated using a complex formula or determined from tables. Ultimately, it turns out that a vessel with a displacement of 500 kg requires an anchor of 5-6 kg, and a vessel with a displacement of 250 kg requires 2.5-3 kg, and so on.
Rule one - the weight of the anchor is approximately equal to 10% of the weight of the vessel being held.
The second rule, which also works, is anchor weight = 1% of the length of the boat (280-2.8 kg; 320-3.2 kg).
Anchor, easily removed from the hook
The fuse itself bends according to the principle of a winding ring. The halyard is tied tightly to the lower end of the anchor. A fuse is attached to the upper end. A ring is attached to the halyard, which is put on the fuse. The part of the halyard between the lower knot and the fuse must form a free loop so that there is allowance for the fuse to bend.
Calculation of anchor weight, selection of rope thickness
Despite the fact that the conditions for using anchors while fishing may be different, and therefore different weights and rope lengths are required, there are several approximate calculations.
For example: Anchor weight = boat length+1 (expressed in kg). Let’s say you have a boat of 3m 70cm, which means that the weight of the anchor, to guarantee the hold of the vessel, must be at least 4kg 700g.
Without resorting to formulas, you can use this table to select the weight of the anchor and the thickness of the anchor rope:
The most common types of anchors:
Anchor cat
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The grapple anchor is a widely used type of anchor.
For small vessels, a folding cat anchor is preferable; on large vessels it can only be considered as an auxiliary anchor due to its low holding force. The folding blades of the grapple anchor minimize its transport dimensions, which is especially welcome on small inflatable boats. The grapple anchor is suitable for use on almost any soil. The retail chain offers anchors weighing from 1.5 to 12 kg in increments of 0.5 kg. For small boats with a displacement of 200-400 kg, a grapple anchor weighing 4-5 kg is sufficient.
The grapple anchor can be used for trawling (searching for sunken gear and other objects).
An ordinary four-legged cat is successfully used on river boats and motorboats; to increase it
For reliability, it is recommended to secure an additional weight on the spindle.
This anchor is popular among fishermen. And the homemade cat anchor was nothing more than a bunch 
reinforcing wire welded in the middle of the length of the rods, the free ends of the rods were bent back like hooks or spikes. The idea was that the hooks could
straighten under load, releasing the hooked grapple anchor, after which the spikes can be bent again to their original position. This anchor can be thrown into rocky crevices, on a heavily cluttered bottom, and in an area like a “cemetery of sunken ships”, without much risk of ending up with an anchor tightly stuck on the bottom.
Admiralty anchor
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The anchor consists of a spindle ending at the bottom with a thickened part - a trend. The bottom edge of a trend is called the heel. Two fixed horns extend from the trend, ending in triangular paws with points - toes. An anchor rod is mounted on the thickening in the upper part of the spindle, perpendicular to the plane of the legs. Above the rod, the spindle is connected to the armature bracket by means of a bolt passing through a hole in the spindle. By its design, the Admiralty anchor belongs to the group of anchors with fixed legs and a rod.
The anchor rod can be wooden, permanently attached, or metal. The wooden rod is used on large anchors. It is permanently attached to the anchor, is less durable than the anchor itself, and requires careful handling. The metal rod allows you to fold the anchor. In the working position, such a rod is fixed with a pin, and in the stowed position, it is shifted and laid along the spindle, for which one of the ends of the rod, remaining in the spindle, is made curved. To prevent the metal rod from falling out under any circumstances, thickenings are made at its ends.
When the Admiralty anchor is released, it comes into contact with the ground first with its paw or heel. When some part of the anchor chain is etched onto the ground, the anchor usually lies flat on both legs, and the rod rests at one end on the ground. After the slack in the anchor chain is taken out and the part of the chain lying on the ground is stretched, it will pull the anchor bracket downwards; the anchor will turn over on the rod, the rod will take a horizontal position, and the paws will become vertical. The rod then acts as a lever. Due to the continued tension of the anchor chain, the lower paw, like a plow, will begin to enter the ground until the spindle lies on the bottom with its entire length, and the lower paw will enter the ground entirely.
A decent holding force coefficient (the ratio of the maximum holding force to the weight of the anchor) is usually about 10-12. It is often higher than other anchors of the same weight and higher than a Hall anchor.
Time-tested simple design, absence or minimum of mechanical parts.
Universal for all types of soil, but compared to anchors of other models it has less holding force.
The design is suitable for a wide range of anchor sizes.
Hall anchor
An anchor with flat legs that rotate on an axis. There are only two main parts: a spindle and a box with paws. The spindle has protrusions at the bottom that form an axis. During assembly, the spindle is threaded through the box, then two bolts are inserted into the box to secure the spindle. The box swings on the protrusions (transverse axis) of the spindle. The angle of deflection of the paws is limited by a groove in the box. An anchor bracket is attached to the thin tetrahedral end of the spindle using a bolt.
The tides on the paws and box serve to make them turn and go deeper into the ground. To increase the holding power of the paws, their tides are equipped with spade-shaped thickenings.
The anchor operates as follows: having fallen to the bottom, it lies flat; when the anchor chain pulls it through, the lower tide of the paws clings to the ground, forcing the paws to turn and pick up the soil with their shoulder blades. In order for the anchor to work reliably, it must be released while moving.
At one time, the anchor made a technological revolution, since its design makes it possible to replace expensive forgings made of high-quality grade iron with simpler, more technologically advanced and affordable cast iron or steel. Design adaptability to mass production 
production contributed to its success.
Although the Hall anchor device (a forged spindle with protrusions threaded through
cast box with claws) remains classic, the design itself has become very outdated for more than a hundred years. The opinion of this anchor as ideal was seriously questioned at the end of the 20th century. The anchor, being one of the first of its kind, soon after its creation gave rise to many new designs (speck anchor, Byers anchor, Union, Danforth anchor, etc.) with greater holding force, more reliable on different soils, incomparably more convenient to be pulled into the hawse. In new designs, the shape of the legs and bosses on the box, the size and shape of the spindle changed significantly, the method of fixing the spindle in the box changed, and the simple axis was sometimes replaced by a ball joint. Sometimes the box began to be made of welded steel sheet. All this made it possible to achieve better results with comparable or even lower costs of materials and labor.
Matrosov system anchor
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Matrosov's anchor has two wide legs adjacent directly to the spindle. Each paw has the shape of a triangle, since the gap between the paws is small, both paws can be considered as one. This design increases the holding force 4 - 5 times greater than Hall anchors. There are bosses on the sides that act as rods that protect the anchor from tipping over. The angle of rotation of the paws is 32 - 350.
Created between 1943 and 1946 by Soviet engineer I.R. Matrosov's anchor belongs to the category of rodless anchors with increased holding force (the force perceived by the anchor without moving or leaving the ground). The design of this anchor includes: spindle; two rotating wide triangular legs adjacent to the spindle; anchor shackle; side rods (tides) protecting the anchor from capsizing. A distinctive feature is the very close location of the turning legs to the spindle.
The design of the Matrosov anchor uses the principle of a crank mechanism, according to which the axis of rotation of the spindle is located relative to the axis of the side rods in such a way that the spindle, when tensioning the anchor chain, plays the role of a connecting rod, turning the legs along the axis of rotation. Penetrating very quickly into the ground, the sailor's anchor cannot be removed from the ground when the ship turns 360 degrees. It is very stable on fine rocky hard ground and holds securely in sandy and silty soft ground. 
Repeated tests on the magnitude of the holding force on various soils have shown the undeniable advantages of the sailor's anchor in relation to the Hall and Admiralty anchors. If the masses are equal, the holding force of the sailor's anchor is slightly more than four times greater than the force of the Admiralty anchor. The anchor is ideal for river vessels, and the wide range of kgf allows you to select an anchor for almost any inland navigation vessel. In addition, the anchor is recommended for large boats and yachts. Since the anchor is lightweight, it is excellent as an auxiliary anchor, which is what is practiced for naval vessels
Bruce's anchor
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Rodless single-horn anchor with increased holding force, developed by the Scottish company Bruce anchor ltd.
Bruce's anchor is one of the varieties plow anchors, has recently become very popular among fishermen. Able to assume the correct position without the help of a hinge.
It has a holding force of up to 30 kg per kilogram of its own weight. The precisely selected shape and correctly calculated design of the Bruce anchor guarantees deep penetration in any case of falling to the ground.
It is a modification of the Admiralty type one-horn anchor. The flat arm of the Bruce anchor is equipped with peculiar bends, which allows it to bury itself in the ground even if it falls to the bottom sideways. The inner side of the spindle of this anchor, facing the paw, is sharpened like the cutting edge of a sword, which allows it to easily enter the ground.
The Bruce anchor, produced in large weight categories, is used mainly as a dead anchor and serves to provide long-term anchorage for lightships, navigational marks, road anchor barrels, oil platforms and other floating objects. However, due to the preservation of high holding force even in small weight categories, this anchor is popular as a deadlift for small vessels (boats, tugs, yachts, boats).
Danforth anchor
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This is a type of ship's anchor with increased holding power, invented by the American engineer Richard Danforth. When tested on sandy soil in April 1948, a prototype anchor showed phenomenal holding capacity.
In the early 1920s, the German engineer Heinrich Hein established the basic requirements for an anchor with increased holding force - legs as close as possible, a rod at the bottom and a “streamlined” head. Danforth's design fully meets these requirements.
The Danforth anchor has a long spindle and flat triangular legs. When it falls to the bottom, it does not strengthen in the upper loose layer of soil, but goes deeper and reaches a solid base, where it reliably “holds” the ship. The extended rod is located in the lower part and serves as a stabilizer that prevents the anchor from tipping over on its side. The anchor box (the junction of the legs with the spindle) is devoid of any protruding parts that prevent it from being buried in the ground.
Danforth developed more than a dozen modifications of his anchor, from lightweight (several kilograms) to heavy, weighing 7 tons.
The Danforth anchor has some disadvantages: in small weight categories it is not very suitable for use on large pebbles, moving along it in jumps, the anchor goes deep here quite rarely. In strong currents, Danforth's light anchor lasts a long time 
drifts in the water and falls to the bottom not where expected. The anchor of this design is sometimes buried so deeply in the ground that it is almost impossible to tear it off the bottom manually.
The distinctive feature of the Danforth anchor is a pair of hinged, pointed “horns” that usually just lie on the bottom, but bury themselves when the anchor is pulled.
When folded, the Danforth takes up very little space and weighs little, while it has a high holding force to weight ratio. This is a proven and reliable design, however, it is still not ideal. Like all designs, the Danforth has changed over the years, and sometimes seemingly minor changes can produce dramatic results.
