home / Furniture/ Diagram of an inflatable boat anchor. Do-it-yourself anchor for a PVC inflatable boat - a step-by-step process

Inflatable boat anchor diagram. Do-it-yourself anchor for a PVC inflatable boat - a step-by-step process

How to determine the weight of the anchor and the dimensions of the anchor rope.

There is no point in carrying a heavy Admiralty anchor on a light boat, but it will be even worse if you go out to the open sea on a cabin boat with a three-kilogram “cat”. It is clear that in the first case it will be busy in vain useful place, in the second - the most tragic consequences are possible.

Let's better estimate what kind of anchor the ship really needs, using approximate formulas.

Anchor weight

W =(8÷10)(3rd root of D 2 ) kgf,

D-vessel displacement, tf.

Anchor chain gauge (link shank diameter)

d =4.7(3rd root of D ) mm.

Table 1. Anchors and ropes for boats and motorboats

The diameter of a rope made from sisal rope, which is less durable than nylon, should be approximately doubled, and from hemp rope - tripled. Comparative data on plant and nylon cables are given in table 3.

Do not forget that the breaking load of the anchor rope should be 40-50 times more weight and the anchor specified in table 1 And Table 2.

How many anchors are needed?

This question usually arises before the captains of relatively large boats and yachts intended for long voyages,

It is considered necessary to have on board a second rig (it can be 20-30% lighter than the main one) and a small (5 kgf) boat anchor or grapple. It is advisable that each anchor be equipped with its own rope.

Which anchor is better?

There is no clear answer to this question.

Admiralteysky (Fig. 20) in terms of holding force, it is 3-4 times inferior to anchors that cling to the bottom not with one, but at the same time with two paws (for example, a Hall anchor), but the anchorage reliability is less, depending on the nature of the soil. When the rope is tensioned, the Hall anchor often turns out due to the heterogeneity of the soil under both legs, so it is risky to accept it lighter than the Admiralty one.

When purchasing an Admiralty anchor, make sure that it is made correctly: the spindle and stem must be at least 2.5 times longer than each horn. As a rule, anchors of this type with a longer spindle also have better holding power.

An ordinary four-legged cat is successfully used on river boats and motorboats; To increase its reliability, it is recommended to attach an additional weight to the spindle.

For large boats and yachts, the Matrosov anchor is recommended (Fig. 21). This is an anchor with increased holding force. Matrosov anchors are produced (welded) with weights starting from 5 kgf, which makes them possible to choose for almost all inland navigation vessels. However, we note that for the safety of the anchorage it is better to have a heavy Admiralty anchor, and not a lighter anchor with increased holding power. Table

Washer instead of pin.

On a standard Admiralty anchor, the rod is fixed in the working position with an adjustable pin. It is not comfortable.

Instead of a pin, you can use a lock washer with a groove ( rice. 22). A spike 1 is welded onto the rod, which passes through the corresponding rectangular groove on the washer 2, loosely put on the part of the rod passing through the spindle. It is enough to turn the washer, moving it close to the spindle, and the rod will be fixed. And so that the rod does not rotate, a second similar spike is made on it 3, fits into the corresponding groove of the hole in the spindle.

Kurbatov's homemade welded anchor.

Welded anchor (Fig. 23) can be made from wire with a diameter of 8 mm, a piece of 12 mm rod and sheet steel 3 mm thick. It resembles the famous anchors of Danforth and Matrosov, but differs from them in that it has only one claw and a forked spindle. An anchor of the dimensions indicated in the drawing weighs about 2.5 kgf and can be used on rowing and motor boats with a mine weight of up to 5 m. It holds well on most soils, but to increase its reliability on rocky soils, where weight is primarily important, it is recommended to have in stock there is a blank weighing 3-4 kgf, which can be put on the anchor end and lowered along with the anchor.

Spindle 1 is bent from wire; a bar is welded into its upper part 6. To stock 3 (does not require any machining) fixing washers 5 and strips must be welded 8, which, when anchor 1 falls to the bottom, turn the paw 2 and force it to stick into the ground. To ensure stability of the anchor on the ground, the rod must have a length not less than that indicated in the drawing.

The ends of the spindle at the rod are connected by a strip 4, which simultaneously limits the angle of rotation of the paw: bar 8 rests against it and holds the paw in the working position. Rib 7 is welded to the paw.

Anchor "Trident".

IN last years The one-legged anchor "Trident" is being used abroad (Fig. 24), not much different in design from the Kurbatov anchor,

The arm of the Trident anchor is wider and has the shape of a trident, so it holds well on soft and loose soil (sand, silt, pebbles). On clay and rocky soil, ballast must be added. A ridge is made across the entire width of the paw, which turns it when the anchor crawls along the bottom; Thanks to the rotation, the paw “bites” into the ground. At the same time, the ridge, resting against the lower strip of the anchor clip, limits the rotation of the paw to a certain angle (about 40°).

“Trident” weighing 2 kgf (foot width 235 mm) is suitable for boats with a length of 3-4 m, and with a weight of 7 kgf (foot width 375 mm) - for small boats and motorboats up to 6 m long.

Three folding cat designs.

Four-legged grapple anchors, which have become widespread on river boats, are inconvenient for storage on a vessel. We recommend making a “folding” cat using one of the ones shown in rice. 25 designs.

At the simplest (Fig. 25, a) cats, the lower part of spindle 1 has a square section rather than a round one 2. A correspondingly shaped hole is made in the sleeve of the upper movable pair of paws. In order for all the paws to be in the same plane, you need to raise the movable pair of paws to the circular section of the spindle, then, turning them 90°, lower them back into place.

In a different design (Fig. 25, b) upper movable pair of paws 4 fixed in working position thanks to a cutout in the sleeve 5. A washer is welded to the spindle 7, which the spring rests on 3, holding a pair of paws 4 in working or folded position.

The third design of a folding four-legged anchor (Fig. 25, V) , which has become widespread abroad, 1 is distinguished by the fact that all paws 4 secured at the bottom; spindle parts 1 articulated coupling 6, sliding along the spindle, locks in the upper or lower position and, accordingly, fixes the paws in folded along the spindle or in working condition.

So as not to lose the anchor.

When sailing through reservoirs clogged with snags and submerged trees, there is a chance of being left behind; without an anchor it is very large. Therefore, release the anchor without tying the buoy to the trend (the junction of the horns with the spindle) (Fig. 26), do not do it. It is best to have a buoy (called a buoy) with a buoy 10-15 m long 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.

When fishing from a boat, you need to think in advance about placing the boat in a stationary state, and therefore choosing an anchor.

Types of anchors for pvc inflatable boats

It should immediately be noted that currently, about 2000 anchors for PVC inflatable boats have been patented. The most common ones are:

Today, the anchor plow is one of the most effective when used on silty or dense sandy soil.

In addition to the above types, the most common and used can be considered the following types anchors: cat, mushroom, river and some others. For example, the cat anchor is quite popular, as it has extremely simple design and at the same time, it works effectively. The mushroom anchor is the best solution for those who like to fish in reservoirs with a sandy bottom. But the river anchor is, in principle, considered the most universal, as it can be used at any depth and in any rivers.

Choosing an anchor and basic requirements for anchors

When choosing an anchor, you should focus on the following criteria:

Holding force coefficient. It is calculated either using special formulas or from table values. Experts recommend focusing more on the weight of the anchor. On average, its weight should be approximately 10% of the inflatable load capacity. The weight of the anchor can also be determined by the following relationship. It must be at least 1% of the length of the boat. For example, if the length is 4.5 m (450 cm), then we multiply this value in (cm) by 0.01. As a result, we obtain that for such inflatable boat PVC, anchor weight must be at least 4.5 kg.
It is necessary to take into account the type of soil in the place where you plan to fish, as well as the nature and characteristics of the reservoir (depths, current strength, as often happens strong winds and other factors). For example, on reservoirs with great depth it is recommended to use a standard plow anchor, but on reservoirs with strong currents, either a mushroom anchor or a Norhil anchor.

Also important requirements for anchors for PVC inflatable boats are: safety, ease of use, compactness, versatility.

How to make an anchor with your own hands

One of the most common and universal anchors, which is also quite easy to make yourself, is the cat anchor.

To make it you will need:

metal rod or pipe, length from 200 mm. – up to 300 mm. and diameter 25 mm. – 30 mm.
a small piece of hollow pipe, diameters 40 - 50 mm.
mounting rings – 3 pieces.
metal sheets – thickness 4-6 mm.

Stages of work:

From metal sheets cut out:
- Four stripes rectangular shape(dimensions: LxW) – 50x20 mm.
- Four strips with rounded edges (dimensions: LxW) – 50x20 mm.
- Eight strips with rounded edges on one side only and drill holes in them for attaching arms (LxW) - 80x20 mm (hole diameter - 5-7 mm.).
- Four triangles (anchor claws).
Mounting rings must be welded to the main pipe (top and bottom).
Weld four strips with rounded ends (4 out of 8) to the bottom of the base.
Weld the remaining strips to the second pipe. It should move freely along the first one.
Drill a hole in medium and long strips - firstly, along the edges - and secondly, only on one side.
Weld the triangles to these strips (to the tapering sides). In the middle part of these strips, make small cuts and bend them. After this, cook in this place. Thus, the horns are given a curved shape. Attach the made horns using metal rods to the lower “ears”. In the same way, attach four-centimeter strips to the ears located on a piece of pipe and then put it on the main pipe. Drill holes in the horns so that you can connect them with rods to holes in the other ends of the four-centimeter strips.

How to increase your fish catch?

Over 7 years of active fishing, I have found dozens of ways to improve the bite. Here are the most effective ones:

Bite activator. This pheromone additive attracts fish most strongly in cold and warm water. Discussion of the bite activator “Hungry Fish”.
Promotion gear sensitivity. Read the appropriate manuals for your specific type of gear.
Lures based pheromones.

Kurbatovsky anchor

For anchor of this type you will need:

leaf part, 3 mm thick;
a piece of high quality metal rod, total length from 12 cm;
wires with a diameter of at least 9 mm.

The main sheet part is attached to a rod 12 cm long by means of a wire, which is pre-fitted to fit the bulk anchor and the whole thing is welded together. In terms of finance, this is one of the most affordable anchors, and manufacturing takes no more than 2-3 hours.

What is needed besides an anchor?

In addition to the anchor, to install the PVC inflatable boat in a stationary position, you will also need a special rope or cable. It is best to choose them from synthetic materials. This is due to the fact that synthetics are stronger and more reliable, and secondly, they are more resistant to external factors.

The anchor cable also has certain requirements:

Strength. To calculate it, you need to multiply the mass of the anchor by 70.
Thickness. Cable, 7 mm thick. and withstands tensile forces of 1000 kg. Suitable for most anchors used for inflatable PVC boats.
Length. There are also certain standards here. It is believed that this figure should exceed the depth in swimming areas by an average of 4-5 times. In addition, it is recommended to use special eye rings to secure the anchor rope.

In fact, it is possible to tie anchor lines to the limit.

It consists in the fact that the anchor cord itself is not passed through the nut earring - it is simply tied to it. The cord is attached to the anchor earring itself in a standard way and is additionally tied with fishing line or wire. In the current version, the risk of getting caught directly on any serious underwater obstacles also disappears. a loop that is formed by the cord itself between two earrings, but this also poses the risk of loss.

Proper use of an anchor

It’s not enough to choose an anchor correctly – you also need to know how to use it. For example, when using a grapple anchor, professionals recommend tying such anchors to the lower part of the loop, and not to the usual upper part. In this case, if you get caught on a snag or stone, you can break off the upper fastening and release the anchor.

The most competent positioning of the boat is with the flow. To do this, you should go a little higher than the parking lot and lower the anchor. The release of the anchor cable depends on the strength of the current and the size of the anchor (usually from 3 to 8 meters). In strong currents, it is recommended to install the boat on two anchors: one at the stern, the other at the bow. Here we first lower the anchor from the bow, and then - after the current has leveled the boat - we install a second anchor from the stern. You can also place the boat on two anchors, lowering them from both sides.

It is important to choose the right anchor type.
For infrequent use, it is worth using anchors that have universal characteristics.
In case of frequent use of the anchor, it is recommended to use an anchor cable made of paracord material, which is characterized by reliability and durability.

The boat is one of the main assistants of the fisherman. You can’t do without it in wild bodies of water, especially if they don’t have clean banks and you can’t catch fish with an ordinary fishing rod. If the angler has a boat, then it is possible to fish in any part of the water area. Unfortunately, the boat must have an anchor to secure it.

This is especially true when there is a current. You can either buy it or make it yourself, which, firstly, is interesting, and secondly, does not take much time and money.

To begin with, it is better to decide whether an anchor is needed for the boat at all. As practice shows, in almost 90% of cases, an anchor is simply necessary. If you have it, you can just go fishing and not think about the fact that the boat can be carried away by the wind or current.

Such a boat element must have the following characteristics:

the weight of the anchor must correspond to at least 10% of the weight of the boat itself;
its mass must be more than 1% of the length of the boat.

Main characteristics of anchors

In order for the anchor to hold the boat under any conditions, all factors should be taken into account:

decide on maximum height waves;
calculate maximum effort wind;
take into account the nature of the bottom of the boat;
choose the right cable for the anchor.

Particular attention should be paid to the quality of the cable, since it will be subjected to great forces. The greater the weight of the boat, the greater the force the cable must be designed for.

Two types of ropes are used for anchors:

artificial. They have long term services, as they do not rot;
natural. They are rarely used due to their low resistance to moisture.

As a rule, it is difficult to choose an anchor for all occasions, especially in a store.

To homemade anchor performed its functions fully, a number of observations should be made:

get acquainted with the weather conditions of the fishing spot;
decide on the design;
prepare the necessary materials;
ask experienced fishermen about a more successful design.

keep the boat in one place;
easy to remove from the bottom of the reservoir;
have little weight;
have compact dimensions and not take up much space;
be resistant to corrosion;
works well on a specific body of water.

Quite often, instead of real anchors, fishermen use improvised means in the form of stones, bricks, ballast with sand, etc.

As a rule, they have low efficiency:

such auxiliary devices are not compact and take up a lot of usable space on the boat;
if there are sharp corners, they can damage the boat;
installing such an anchor takes a lot of valuable time.

The use of such devices is justified if the bottom of the reservoir is hard and clean. Despite this, factory designs do not always meet the necessary requirements.

The disadvantages include:

high, sometimes unjustified price;
products may simply be defective.

If we take the above into account, then it is easier, cheaper and more affordable to make an anchor yourself. Moreover, the fisherman understands what kind of anchor is needed to make fishing comfortable.

Types of anchors for a PVC boat with your own hands - photo drawings

Without an anchor, especially in the current, you can hardly count on fishing at all. But this does not mean at all that an anchor will not be needed on a body of water without a current. As a rule, underwater currents may be present in any body of water. In addition, there is not a day without wind, which is capable of driving a boat across a body of water without problems. Having an anchor will help solve many problems. In this regard, the presence of an anchor should not be underestimated, especially since making one yourself is not so difficult. The most popular designs today are the following:

Hall anchor;
cat anchor;
anchor-Kurbatova;
a mushroom-shaped device for fishing in the current;
Danforth anchor, designed for any type of bottom.

Each design has its own advantages and disadvantages. To understand which option is most suitable, you need to consider each design in detail.

To make it you need to have the following parts:

metal pipe, diameter 25 mm and length 270 mm;
one nut and one bushing;
four pieces of metal: two smaller and two larger;
two metal rings;
two kilograms of lead.

Assembly:

A sleeve is attached to the end of the tube. Four strips of steel will serve as paws. The entire structure is held together with a nut. To increase the weight of the anchor, lead is poured inside the tube.

This welded structure, so fewer parts will be needed. Here they are:

steel rod;
steel wire;
metal pieces.

You need to bend the wire into something similar to a spindle, and the rest of the parts are welded to this blank. Due to the welded pieces of metal, the structure is securely held at the bottom.

This anchor is perfect for small PVC inflatable boats. As a rule, it is a folding structure that takes up a minimum of usable space. The design is quite light and in the presence of wind it needs to be weighted down. The arms of the anchor are attached to a kind of spindle bent from wire. The position of the paws can be adjusted by moving them along this wire.

To make such a structure, you need a pyramid-shaped shape. Alternatively, it can be made from iron sheets. After this, the mold is filled with molten lead. So that the anchor can be fastened, after pouring, a piece of wire is inserted into the still hot lead. After the lead hardens, the wire is securely fixed in the structure. The second option allows you to do without lead. It involves attaching plates of various sizes to form a pyramid. The advantage of this method is that you can easily adjust the mass of the armature by removing or adding plates. This is easy to do if you take metal pin with threads, and drill a hole in the center of each plate. The entire structure can be fastened with a nut. In this case, you should dial up the platinum so that the smallest one is at the bottom.

Making an anchor with your own hands is not difficult. It is much more difficult to learn how to use it. If you don’t do this, then losing it won’t be a big deal, but making an anchor for every fishing trip is very expensive. Therefore, it is important to know how to fish without losing the anchor.

How not to sink an anchor

Each body of water is characterized by its own type of bottom, which may vary depending on the various areas the same body of water. Therefore, it is difficult to determine if a device is located on a hard or muddy bottom unless you try to study it. Unfortunately, most anglers don't do this. To avoid leaving the anchor at the bottom of the reservoir, you need to do the following:

anchor to the trend;
provide it with a buoy;
pull out using a buoy rope.

As a rule, for the normal functioning of a PVC boat, one anchor is enough, especially if correct operation. The main thing is that the design is reliable, and weather favored the process fishing. Despite this, it is better to play it safe and take another anchor with you, as they say, just in case of emergency. At the same time, it is very important to take into account the nature of the bottom of the reservoir. Sometimes you have to move from one body of water to another, where the bottom may be completely different. Therefore, it is better to have two anchors: one should be intended for a hard bottom, and the other for a muddy bottom.

Conclusion

Fishing is exciting activity, which brings a person mass positive emotions, which contributes to a charge of vivacity and energy. But this only happens if the fisherman has thought through everything to the smallest detail and has taken all the necessary accessories with him. Moreover, they must be of high quality and comply different conditions catching A similar definition applies to boat anchor. If it is a high-quality and functional assistant, then besides pleasure, fishing will not bring any negativity. If the element turns out to be of poor quality, the fishing process may be ruined. This process will cause nothing but great annoyance.

In anticipation of the next sailing season, having racked my brains in my head or what I have there, using my hands, which are far from the straightest, I made an anchor for a rubber boat, or rather for my sailing catamaran, plowing the northern Ladoga expanses with the proud name “Kotya”. I need this accessory, first of all, because when I go on a trip I “park” the catamaran on the water. I’m too lazy to drag it ashore, and most importantly I feel sorry for the PVC cylinders, after all, the stones on Ladoga are like a good grater. Until now I have used a folding “cat” that weighs a couple of kilos, but it doesn’t hold up well on rocks or even on the ground. If it doesn’t catch on a good stone, it breaks off, but good stones Unsurprisingly, there are very few skerries at the bottom.

If anyone is interested in how make your own Danforth anchor without use welding machine, making do with only commonly available tools - a drill and a grinder, then about this. Well, now we will talk about much more simple version anchors

But to the point. A homemade anchor weighing 9 kg was made in about twenty minutes (not counting 1.5 hours of drying the paint) from automotive junk that was on hand, without any drawings, and the only tools used were a drill. The idea was born and formed in general outline literally in a couple of minutes.

What it took

an old brake disc from some kind of car;
a rusty cover from the brake chamber of some truck;
found threaded rod;
mounting clamp, also from the brake chamber;
castle nut from who knows what;
washer d30 or so, it’s not clear why;
nut M16 = 2 pcs;
bolt M8x40 = 3 pcs;
nut M8 = 3pcs;
body washer M8 = 3 pcs;
a piece of rubber hose.

THE PROCESS OF MAKING AN ANCHOR WITH YOUR OWN HANDS

First of all, after going through the cardboard a little, I removed only a thick layer of rust and painted it (we used paint that can be applied directly to the rust). Next, connect the brake chamber cover to brake disc, drilling 3 holes in it (mark according to the holes on the disk). We take M16 bolts, nuts, washers and twist our pieces of iron.

Screw one nut onto the threaded rod. To prevent it from accidentally unscrewing, I slightly knocked down the thread at the end of the rod.

We throw on the d30 washer and pass the rod into the hole in the chamber cover. We put a castle nut on top (can be replaced simply with a washer) and tighten the resulting structure with an M16 nut.

We put on the rubber hose and screw the fastening clamp. All. We wipe our hands. A homemade boat anchor is ready.

What is good about it, in my opinion, specifically for a PVC boat and specifically for my catamaran, is that it does not have sharp corners. In addition, it can be easily disassembled for transportation. And of course, it’s very nice that not a penny was spent on production.

Owners of small watercraft are encouraged to make an anchor completely with their own hands not only by the fairly high price of factory anchors. Standard anchors are produced weighing from 5 kg, which is a bit much for a boat with a displacement of up to 500 kg. Especially if they go out into a closed, calm water area (pond, small lake, river). The anchor alone takes up a lot of space in the vessel, and in a tiny boat, such as, for example, popular due to its high quality a dinghy boat or skiff, holding an unreasonably large anchor is inconvenient. But you can’t stand on just anything instead of a reliable anchor.

It was not for nothing that Joseph Conrad called anchors “honest pieces of iron”: neglecting the reliability of an anchor can cost the life of the boatmaster and passengers even close to the shore. A homemade anchor should hold the ship as firmly as a proprietary branded one, and should not get lost in the ground more often than it does. The reliability of commercially available ultra-light anchors is not guaranteed. Do not trust company certificates: no marine or river register will include an anchor weighing less than 5 kg in its register. Prohibited by international navigation safety regulations. And they, like army regulations, are written in human lives.

A real tangle of problems is the PVC boat anchor. Firstly, the anchor is only part of the anchor device, consisting of several structural units. Each of them, according to the main rule of strength of strength, “Where it is thin, it breaks,” must be no less reliable than the anchor itself. There is simply nowhere to place all this in an inflatable boat. Secondly, when budget inflatable boats price category began to be made not from tire rubber or rubberized fabric, but from plastic, it turned out that even a raised anchor in such a boat could be dangerous - the number of accidents on the water caused by the rupture of the cylinder or the bottom of the boat by the anchor increased sharply.

The purpose of this article is to help a novice boatmaster solve the problem of choosing a prototype anchor for his vessel and tell him how to properly make an anchor in accordance with the type of vessel design, its displacement and sailing conditions. A significant part of the material is devoted to the choice and features of the manufacture of anchors for “ultra-small” vessels (up to 0.5 tons) operating on inland waters. The bottom in them is often marshy, muddy or peaty; in such a situation it is difficult both to ensure the proper holding force of the anchor and to prevent it from sinking into the ground.

Note: All inflatable boats have one more difference from normal displacement vessels - very low frictional resistance against the water. An inflatable boat clings to the water less strongly than a glider. On the one hand, this is good for calm water, since it is easier to keep the boat in the current. But in excitement, on the contrary, it is more difficult, because... the float boat tugs hard on the anchor rope. And anchoring an inflatable boat is also more difficult: he cannot rely on the vessel to pull him, lay him down properly on the ground and help him cling to him. Here, the anchor for an inflatable boat must rely only on itself: it should be laid correctly without a jerk from the vessel and have absolute tenacity (see below).

Is the cat an anchor?

To people who go fishing on an old rubber boat, all these considerations may seem far-fetched: of course, it is known that the long-established anchor for a rubber boat is a cat. And it’s not difficult to make: three pieces of reinforcement, two of which have flattened ends, a little bending, a little welding, and the cat is ready. And the tenacity of a cat is absolute if thrown correctly. It is not without reason that hook cats are used in other activities.

Firstly, in terms of holding power, the cat anchor is quite average. True, for a boat that glides through the water almost like a fallen leaf, this is not so significant. Another significant thing is that it is very easy to lose a cat on rocky or muddy ground. When scrap metal is lying everywhere under your feet, and the master at work and without a bottle allowed you to use welding and bending machine, it didn't matter, but these are different times.

Secondly, even then there were plenty of accidents on the water due to grapple anchors. And now it has turned out that a cat is dangerous not only in a PVC boat, but also in one made of plywood without a hull, like the same dinghies or skiffs. Molded folding crampons are safe, hold an ultra-small boat well on any ground, are compact, but are unfairly expensive. Although for a sewn boat with a rigid hull approx. A 2.5-3.5 m long homemade folding cat with a swivel paw is also suitable, see for example. video

Video: homemade cat anchor

However, in a PVC boat, even such a cat turns out to be bulky and dangerous for the vessel. Therefore, including what is said above, coastal residents big water, a cat is not considered an anchor at all. And a sailor will never say: “give up the cat” or “stand on the cat,” just as he will not say “drop anchor.” A cat is not an anchor. But it is still possible to turn a cat into an anchor! Specifically for low water inflatable boats with a displacement of up to 300-400 kg. Moreover, it is very compact, convenient, reliable and safe. How exactly – we will return to this later.

Basic Rules

Weight and cable

The main thing that determines the reliability of an anchor is its mass, weight. For rowing and motor boats with a rigid hull up to 5 m in length, the mass of the anchor must be taken at least 1% of the displacement of the vessel when fully loaded, but for a displacement of up to 500 kg - at least 2.5 kg. For the same vessels equipped with permanent or standard removable sailing rigs, the weight of the anchor is increased by 25-50%, in case of anchoring under the spar. If the anchor is Admiralty (see below), its mass is increased by another 20%. The tensile strength of the anchor chain or cable must be at least 50 anchor weights.

Note: The reliability of the anchor is greatly increased by replacing the part of the anchor cable closest to the anchor with a chain. For a boat up to 4.5 m long and with a displacement of up to 500 kg, it is enough to replace the first 1.5-2.5 m of cable from the anchor with a chain.

It is advisable to take the weight of the anchor for inflatable boats used in inland waters according to their human capacity. The calculation formula, if there are no sails and the boat can carry no more than four people, is simple: anchor as many kg as there are people holding the boat, and add 0.5 kg. With sails and chain it is more difficult; general data is summarized in the table:

Capacity, persons	Anchor weight, not less, kg (boat without sails)		Anchor weight, not less, kg (boat with sails)	Anchor chain gauge, not less, mm (boat without sails)
1	1,5	3,5	2,5	4,0
2	2,5	4,0	3,0	4,5
3	3,5	4,5	4,0	5,0
4	4,5	5,0	5,0	6,0

Note: if the anchor is Admiralty, its mass is increased by 20% compared to the tabular one.

Center of gravity

The next point is the distribution of the mass of the anchor over its height (assuming that the anchor is vertical). An anchor that is overweight at the top will drag along the bottom, bouncing, and will not catch on. An anchor that is too heavy at the bottom may sit on its heel and also not catch, or it will be sucked into the ground. The center of gravity (CG) of the anchor should be 1/6-1/8 of its height, but for anchors different types its position is fixed. Therefore, even experienced shipbuilders do not allow themselves to arbitrarily change the proportions of anchors. If you have to do this, then you need to look at where the CG of the prototype is located, in the standard for it, or, if this is unknown, then calculate it. The center of gravity of a homemade anchor should be at the same relative height as that of a standard anchor or a practice-tested sample.

Weight and holding surface

The ratio of the mass of the anchor to the area of its holding surface is also important, i.e. to the surface of the feet, normally buried in the ground, counteracting the traction force from the vessel. Anchors in this regard obey the square-cube law: when the size of the anchor changes, its mass changes along the cube, and the holding surface changes according to the square. If, for example, you reduce the size of a standard anchor to fit your vessel, then its weight will decrease relative to the holding surface, and the anchor may lose reliability. Therefore, the dimensions of the anchor will need to be changed so that the mass/holding surface ratio remains within acceptable limits. And for beginners, don’t be tricky with the dimensions of the chosen sample.

Note: A way to bring the weight of a reduced anchor to normal is to fill part of the hollow spindle (see below), or the entire spindle, with lead. We will remember him again.

Tenacity

For ultra-small sewn and inflatable boats, the tenacity of the anchor is of particular importance. It is characterized by how much tug is needed on the anchor rope/chain in order for the anchor to fall into the desired position, and how long it will drag before it catches. Anchors are considered absolutely tenacious; they themselves lay on the bottom as they should and immediately bite into the ground. For any small boats, these are the ones you should choose.

Types of anchors

Anchors have been used by all those floating on water for thousands of years, and thousands of their designs have been invented. But in practice, few have taken root - the anchor is extremely important for the safety of navigation.

The types of currently common anchors and the names of the main parts of the anchor are shown in the figure:

If a cable or chain is attached not to a freely dangling ring - an eye - but to one fixed rigidly on a spindle, or to a bracket, rotating or tightly fixed, then this is no longer an eye, but a butt of the anchor. Very often, a small eye or butt is attached to the trend, and a thin line - buirep - with a buoy floating on the surface of the water is tied to it. Pulling on the buoy rope most often manages to free the stuck anchor, but if you pull on the cable/chain, it only clings more tightly.

Note: What does M mean, see below.

The Admiralty anchor has been known since the Stone Age: then it was made of wood with a stone stem. This anchor is reliable on any bottom, but, firstly, it is heavy, because... realizes no more than half of the potential holding force, and is cumbersome. On old sailing ships, it was raised and hung from special powerful beams, called crambols, sticking out obliquely from the bow of the ship. Secondly, in shallow water or when the water level drops (for example, at low tide), the ship can sit with its bottom on the anchor horn sticking up. You can partially eliminate the bulkiness by making the rod removable. The great advantage of the Admiralty anchor is its simplicity of design and proportions, verified over centuries, see fig. on the right, and suitability for vessels of any displacement, including toy boats. To obtain the dimensions of an Admiralty anchor of less weight, straight lines in Fig. just extend to the left. A serious drawback is weak tenacity: in order for the rod to tip the anchor into the correct position and the paw to bite into the bottom, you need to pull the cable/chain quite hard and drag the anchor. The Admiralty anchor can be recommended for boats equipped with sails and going out into deep water.

The Porter (more precisely, Porter-Trotman, in the figure) and Northhill anchors are modifications of the Admiralty one. Rarely used, because are not without its disadvantages, giving in return few advantages. Hall's anchor is a truly brilliant find: Hall came up with the idea of entrusting the task of the rod to the loose legs with a skirt at the bottom, and to ensure full grip of the anchor, he made them rotatable. Hall anchor for ships approx. from 5 tons of displacement has no disadvantages and currently absolutely dominates the fleets. But it is also applicable for inflatable boats without sails: the ratio of weight to holding surface is too small in this case compensated by the low friction of the boat on the water. Therefore, we also give standard proportions of the Hall armature (see figure), for comparison with amateur samples.

Note: The Hall anchor is a technologically complex product. For its reliability, the location of its centers of gravity is also important. components, which is also normalized.

Letter M in Fig. with types of anchors denotes the Matrosov anchor (see figure). In the vessel's displacement range of approx. 1-100 t it turns out to be more reliable than the Hall anchor with a lower mass; especially on weak bottom soil. The Matrosov anchor is interesting to us because its method of creating holding force is fundamentally different than that of the Admiralty and Hall anchors: the Matrosov anchor is actually one-legged. This method allows us to create absolutely tenacious anchors of extremely low mass for very light ships, which is what we need.

Matrosov’s idea was brought to its logical conclusion by Danforth, who designed an anchor in which the ratio of mass to holding surface is theoretically equal to... 0! That is, the Danforth anchor (see the next figure for its drawings and dimensions) can, in principle, be made even from paper, as long as it does not get wet and break. But - up to a certain upper limit of the vessel’s displacement; This is where the square-cube law comes into play. For those who know something about mathematics: Danforth realized what part of the curves on the graph of certain characteristics of the anchor can be approximated by a straight line, the derivative of which, as is known, = 0.

The Danforth anchor dominates small shipping as much as the Hall anchor dominates large shipping. To recalculate its dimensions to a smaller mass is simply the same as for the Admiralty: we do linear extrapolation, and that’s all. The fork anchor is theoretically the same Danforth anchor, only more technologically advanced for self-made and more reliable on a rocky bottom: it is more difficult to break one powerful paw than one of two of the same total area.

Note: Matrosov and Danforth anchors are often supplied to large ships as spares or werps (taken out on a boat).

The plow anchor is also theoretically “zero” and has no equal in terms of specific holding surface area, although its tenacity is approximately the same as that of the Admiralty. Therefore, patented plow anchors different types(Delta, Bruce, etc.) are quite popular abroad among sailing yachtsmen on ocean-going yachts. But storing an anchor-plow on a ship is extremely inconvenient. The only suitable place for this is the bow roller, and even then, the plow anchor, in addition to the tightly stretched anchor chain, has to be tied down with three more cables: an upper one and a pair of side ones, so that the hole in the hull is not plowed. Anyone who has gone out to sea, even with a bull on an elastic band, will read about this fashionable fad and just shake their head: what if the plow anchor needs to be quickly released at night during a storm? What will happen then? We are interested in the plow anchor because it is the origin of the mushroom-shaped anchor, which is undeservedly little known to owners of PVC boats, see below.

Note: in large-scale shipping, fire guards are often placed on plow anchors - ships without power, assigned for a long or eternal stay in a certain place in the water area (floating warehouses, berths, guard posts, barracks, prisons, etc.).

About Kurbatov's anchor

Among fork anchors, the Kurbatov welded anchor is popular among domestic amateurs (see figure below). It holds a boat well with a displacement of approx. from 300 kgf on our usual bottom soils: sandy, clayey, silty. In the northern United States and Canada, where the bottom of river streams is often rocky, the Trident anchor with a 3-prong double-width fluke (bottom right in the figure) has proven to be more reliable. The second thing that can be said about Kurbatov’s anchor is that it doesn’t hold 1-2 seater inflatable boats on calm water in windy weather; it crawls along a weak bottom. Since in this case the matter is corrected by the weight (see below), it remains to be assumed that the low weight of this anchor has an effect. Danforth developed the theory of a zero-mass anchor, but its actual weight still affects the properties of practical structures. And this can be very useful specifically for the anchor of a PVC inflatable boat, see below.

About floating anchors

A drogue does not hold the ship in place. He holds it with his nose against the wave or current. In fleets, standard floating anchors are rarely used, except on expedition ships. Probably from a sailor's superstition: during a voyage or voyage (if the ship is a military one), the sea anchor is most often thrown out when it is time to give an SOS. Any floating anchor operates on the principle of a parachute.

However, in amateur fishing, floating anchors find quite utilitarian use. Some species of fish swim downstream in a school to feed, and then leave the core and return to their original position. It is clear that by staying in a boat above the school, you can expect a larger catch.

It is very easy to make a fishing anchor for a PVC boat from 4-5 2 liter PET bottles, holding them in a row with tape. Then the ends of a nylon cord are tied to the necks of the outer bottles, a loop of it is tied behind the bottoms and tied with the same tape. The rope from the boat is tied to a loop of the cord. So it is necessary that the bottles meet the flow of the current with the most streamlined surface, and rely on the thrust from the boat to rest against the least streamlined water, as befits a parachute. Setting up such a sea anchor for almost any boat is also easy: to do this, the bottles are partially filled with water or sand.

How to get rid of a stock

Let's take another look at the drawings of the anchors most suitable for inflatable boats: Danforth and Kurbatov. What is bad about them for a PVC boat? Right. Stock. It gets in the way in a tight boat and can damage it.

“Theoretically-paper” Danforth anchors are necessarily equipped with a rod (on the left in the figure); without it, they lose the properties of self-alignment, absolute tenacity, and on a loose bottom they become unreliable. But let's think again: after all, a real anchor definitely weighs something. How to use its mass to get rid of the stem while maintaining all other qualities? The result is (see photo on the right in the figure):

Let's increase the mass of the anchor by making it (by dimensions 220..250x350 mm) legs are made of 5 mm steel, the spindle and axis of the legs are made of 14 mm rod, and the butt is made of 10 mm.
Move the paws away from the spindle for approx. by 1/5 of their width.
Let's replace the installation blades-limiters of the Danforth anchor with a skirt, similar to that of a Hall anchor, and protrusions welded onto the lower end of the spindle, against which it will rest (the angle of rotation of the paws is 30 degrees).
At the same time, we will round the ends of the paws so that we certainly do not tear the boat.

And - amazing thing! This hybrid anchor also turns out to be absolutely tenacious and self-aligning! Unfortunately, there is no theory for it yet. In the same way as for rodless anchors for inflatable boats with Hall camber, see Fig.

How to make the anchor on the right in the figure with your own hands, which looks similar to the Hall anchor, and download its drawings, see the video:

Video: homemade anchor for a PVC boat

Danforth's anchor is still a teenager among his brothers, and sometimes unexpected properties are discovered in him. So, for example, if the same boat and under the same sailing conditions, which the Kurbatov anchor does not hold well (see above), is equipped with a Danforth “paper” anchor weighing only 1 kg, it will hold it. And another amateur idea, proven in practice, is to make a Danforth anchor for a 1-2-seater boat PVC detachable legs, rearranged either with a convergence towards the spindle, or with a camber outwards. In the first case, it will be better to hold the anchor on dense and rocky soils, and in the second - on a loose, weak bottom. How to make a transformer anchor for a PVC boat, see next. video:

Video: DIY transforming anchor

One thing is clear: Hall’s method of self-installing the anchor at the bottom using the camber of the legs and the skirt allows you to get rid of the rod. Many amateurs, without knowing it, make themselves lightweight anchors with increased holding power with claws and a rod, like the original Danforth one, see fig. below. But in this case, the anchor needs a rod like a ship’s cat needs a canary seed. Without a rod, such an anchor will only cling faster and become more reliable.

And yet the cat is an anchor!

It's time to remember the cat anchor and at the same time the mushroom anchor, because... they are also interconnected. The path of origin of the mushroom anchor from the folding cat is illustrated by the left part of the trace. rice. The good thing about a mushroom anchor is that when minimum sizes and complete safety for an inflatable boat, keeps it on a very, very weak bottom - deeply silted, floating fine sand, etc. And also because its size and weight are smaller than other anchors, depending on the length and displacement of the vessel. However, a mushroom-shaped anchor for a marshy bottom must be equipped with a butt on the trend: it is impossible to pull it out by the eye or butt if it gets pulled into the ground without scooping it up with the side.

You can make a mushroom-shaped anchor from the bottom of a household gas cylinder; Already an anchor from the bottom of a 5 liter cylinder reliably holds a 1-2 seater PVC boat. The bottom of the cylinder is cut off where it meets the vertical walls (the tangent slope is the same as that of the Admiralty anchor - 40 degrees). 3-4 holes with a diameter of 30-40 mm are cut into the bottom so that the soil is pressed through them and does not clog the anchor blade.

The spindle of a mushroom-shaped anchor from a balloon is made from a piece steel pipe with a diameter of 40-60 mm. Its length for 1-2 seater boats is from 200 mm; for 3-4 seater – from 300 mm. The butt of their bent 10 mm reinforcement is welded to the top of the spindle. And to the trend - a 6-8 mm shank. For complete reliability of such an anchor, the spindle is filled with lead at any bottom.

The evolution of the grapple anchor can be taken along a different path, as exemplified by the drawings of a folding mini-anchor for a 1-3-seater PVC boat in the rest of the picture. Its method of creating holding force is completely unique: when dragged, this anchor turns, screwing into the bottom soil or clinging to stones with its paws. For greater reliability, it is advisable to weld its spindle from pipe sections and fill it with lead. The tenacity of this anchor is not great: it needs to be wired about a meter to secure it properly. But the folded mini-anchor can be carried in your pocket, and it is a non-losing anchor: a tug on the anchor-cable is enough for its stuck paw to come out of the crack or for the anchor pulled into the swamp to go up (vira, as a sailor would say).

Cat made from scrap materials

The grapple anchor has one more advantage: it can be made from scrap materials. Specifically - from a pair of crooked fragments or cuttings of branches for paws, stone suitable size and a mold, and also a piece of a crooked branch or flyer for the spindle. The paw branches are tied crosswise, a stone is tied to the crosshair; then add a flyer or a spindle branch to it. There are cases where people survived in extreme conditions thanks to a homemade grapple anchor made from scrap materials.

Note: However, do not forget that the congenital defect of any grapple anchor is that the boat can sit on its paw with its bottom!

If there is something wrong with the anchor

For sewn and, especially, inflatable boats, the weight and compactness of the anchor are of decisive importance, so anchors for them should be made as light as possible. But what if the anchor crawls?

A way to increase the holding force of an anchor has been known for a long time: a weight on an anchor-cable or anchor-chain, top left in Fig. Anyone who remembers school physics can easily calculate that a load of half the weight of an anchor can double its holding force or more. For a light anchor of an inflatable or sewn boat, a lead weight of 1-2 kg is sufficient; it won't take up much space. For installation on the cable, the weight is equipped with a carabiner; it can be firmly secured to the weight. They lower the load on a fishing line, which is always at hand when fishing.

Another emergency situation with the anchor is stuck. The way to free a stuck anchor is also known: a buoy attached to a trend and a float buoy. To get the anchor out of the dead hook, pull the buoy rope. If there is no support for it at the anchor, and the bottom is obviously “mean” (marsh, rocky), the buoy can be tied to the trend, as shown in Fig.

On small vessels, holding a buoy and a buoy is often inconvenient. If the anchor has swivel legs or one of its modifications, a radical means of turning the anchor into a non-losing one is a sliding eye, pos. a-d in Fig. The most reliable is the sliding eye in pos. c, but the anchor with it is cumbersome. Release the anchor as shown in pos. d: they allow the ship to move against the tension of the anchor cable.