The choice of anchor for an inflatable vessel is often a cause of heated debate among water-engineers, some argue that a light boat is enough and kilogram cargo, while others are reinsured, taking with them 10-kilogram anchors, which can hardly be called safe for inflatable tubes.
To make matters worse, inflatable boat manufacturers rarely specify specific anchoring guidelines, limiting themselves to general phrases about "safety." In this article, we will examine the physics of the process, mathematical formulas for calculating mass, and the types of designs that are ideal for the purpose of anchoring. PVC boats with their limited capacity.
An improperly selected mass of anchor can lead not only to the demolition of the boat on the stones or fairway, but also to damage to the transom or sides. Let's figure out how to find the "golden mean" between the reliability of the fixation and the safety of your boat.
Factors affecting the choice of anchor mass
Many people mistakenly believe that the weight of an anchor depends solely on the length of the hull of a boat. This is not quite true. The basic parameter that really determines the mass required is the area of sailing of your vessel. The higher the side and the larger the usable area, the more the wind will push the boat, creating a bearing force.
The second critical factor is the strength of the current and the depth of the berth, and in the fast flow, even a small load may not hold the boat if it is not of the correct shape, and the depth affects the length of the anchor shaft: the deeper the rope, the longer the rope, and the greater the angle of demolition, which increases the load on the anchor.
It's also important to consider the material of the bottom, because it's not so much the weight that matters for the clay or the muddy bottom as the shape of the paws that allows you to burrow. cat anchor It might just get stuck, and then its weight becomes secondary, and the main task will be to get it out.
⚠️ Warning: Never tie the anchor tile to the bow of the boat without the possibility of a quick reset. In high winds, the boat can turn the side to the wave, which will lead to its rapid flip.
Mathematical calculation: formula and table
There is a time-tested empirical formula that calculates the minimum weight of an anchor, which takes into account the displacement of a vessel, which is more accurate than just length. M = k ∛(L B * H)where L, B, H is the length, width and height of the side, and k is the coefficient, depending on the material (for PVC it is usually 1).
However, for practical applications, it is easier to focus on hull length and wind load. Below is a table drawn from years of experience in operating inflatable boats of various sizes in temperate latitudes.
| Boat length (m) | Min. anchor weight (kg) | Optimal weight (kg) | Max. Weight (kg) |
|---|---|---|---|
| 3.0m | 1.5 - 2.0 | 2.5 - 3.0 | 4.0 |
| 3.0 - 3.6 m | 2.5 - 3.0 | 3.5 - 4.5 | 5.0 |
| 3.6. to 4.2 m | 3.5 - 4.0 | 5.0 - 6.0 | 7.0 |
| 4.2. to 4.8 m | 5.0 - 6.0 | 7.0 - 8.0 | 10.0 |
It's worth noting that these values are relevant for classic anchors with paws (Denforth, Hall). cat-anchorIts weight should be about 20-30% higher than the specified values, since its holding power is lower.
If you're fishing on the current, add another 30 to 40 percent to your estimated weight, which compensates for the dynamic load of water on the boat hull.
Types of anchors: what to choose for an inflatable boat
The range of anchors is large, but not all are suitable for PVC boats, the main criteria for choosing are the absence of sharp edges that can damage the balloon, and compactness in folded form. The classic Admiralty anchor immediately disappears due to its bulkiness and sharp horns.
The most popular solution is the cat anchor, which is a versatile tool that can be assembled independently from metal bars, and its paws fold, which is convenient for transportation, but it has a significant disadvantage - low holding capacity on hard ground.
- 🐙 Cat anchor: It is ideal for rocky bottom, easy to extract, but requires more weight for reliable fixation.
- ⚓ Denforth anchor: It has excellent holding power due to its wide paws, but can be bulky and have sharp edges that are dangerous to PVC.
- 🪨 Cargo (stone, sandbag): It is used as a passive anchor, good on a stained bottom, but does not hold on to the flow.
There are also specialty inflatable boat anchors made of stainless steel or rounded aluminum. They are light but expensive. For most anglers, the best choice is an upgraded cat or a compact Denforth with protective paws.
How to make an anchor-kosha yourself?
Take a metal pipe with a diameter of 25-30 mm. Weld 4-6 bars of rebar (diameter 10-12 mm) 30-40 cm long. On the free ends of the bars, put on segments of a rubber hose or plastic tubes so as not to scratch the bottom of the boat. Weld a ring on top to fasten the tile.
Effect of soil type on retention capacity
Weight selection is half the battle. The second half of success lies in understanding how the anchor behaves on different types of bottom. On sandy ground, the anchor must be able to burrow, so it's important to have sharp legs and enough weight to get the initial hook.
On a clay bottom, which is common in rivers, an anchor can slide across the surface if it doesn't make enough effort to "gnaw" -- mass plays a key role -- or it can suck the anchor in such a way that it's impossible to pull it out without a boat.
If you plan to fish in areas with diverse bottom relief, it is better to have a margin by weight. A light anchor on hard clay turns into a useless cargo that will drag along the bottom, scaring the fish and erasing the fail.
⚠️ Warning: When using an anchor on a sluggish bottom, always leave a margin of the length of the falter so that you can approach the anchor vertically and pull it upwards rather than dragging it with a drag.
☑️ Checking the anchor system before exit
Anchor shaft: length, material and fastening
The weight of the anchor is directly related to the length and material of the anchor shaft. There is a golden rule of anchoring: the length of the shaft should be equal to the length of the shaft. two or three depths This provides the right angle of attack for the anchor, allowing it to burrow into the ground, rather than just lying on the bottom.
For inflatable boats, it is strongly recommended not to use chains as the main part of the fall. The chain is too heavy and can damage the balloon. The optimal choice is a synthetic cord (nylon, polypropylene) with a diameter of 6-8 mm. It is durable, does not rot and feels pleasant.
Mounting the façade to the boat should be carried out through a special rim bolt installed in the bow. It is strictly forbidden to tie the phala to the leer rings (pens) along the side.As the boat may flip or tear off the handle when snatching, this will result in loss of tightness.
For ease of control of the phalanx, you can use a simple block system or anchor rail, which allows you to raise the anchor without tilting far overboard, which is especially important in high wave or high winds.
Safe anchoring technique
The anchoring process requires a certain skill: approach the parking place must be against the current or against the wind. The anchor should be lowered when the boat still has inertia of movement, so that the falt does not get entangled around the propeller (if the engine is not raised).
Once the anchor has touched the bottom, you need to pit the desired length of the fail and slowly let the boat pull it, then you need to give it back a little or give it to the gas (caution!) so that the anchor is buried, only after that you can finally fix yourself.
- 🌊 Always assess the direction of drift before throwing anchor.
- 🚫 Do not drop anchor if there are communications or protected areas under you.
- 🔪 Have a sharp knife on hand in case the tile winds on the screw or you need to leave urgently.
You also need to get off the anchor against the current, picking out the slack and going to the parking point. If the anchor is set, use the rocking technique: approach the anchor from different sides, choosing the slack until it comes out of the ground.
The safety of an inflatable boat when anchoring depends not so much on the weight of the anchor as on the correct length of the phala and its reliable attachment to the nose rim.
Can a brick or a bag of cement be used instead of an anchor?
You can use it, but it's inefficient and it's not safe. A brick can split and damage the boat, and a bag of cement will get wet and it will become too heavy to lift by hand, and they have zero holding capacity on the flow -- they just lie on the bottom.
What is the optimal diameter of the rope for an anchor?
The optimal diameter of a nylon cord is 6-8 mm. The thinner will cut the hands when sampling, and the thicker will take up a lot of space and be unnecessarily rigid. The length should be at least 15-20 meters for most bodies of water.
Do you need a vertebrae at anchor?
Yes, a vertebra between the phalanx and the anchor is highly desirable, preventing the rope from twisting when the boat is unfurled by wind or current, and helping the anchor to take the correct position for the hook.