The right anchor is not just a matter of convenience, it's a critical safety feature on the water, and many boat owners make the mistake of relying on intuition or buying the first cargo they get from a hardware store. retainer It depends on the complex interaction of the mass, the shape of the anchor, the type of soil and the length of the chain.
A miscalculation can cause your boat to be blown by the wind or by the current at the most inopportune moment, such as during fishing or overnight stays, especially for light inflatable boats, where the balance between the weight of the cargo and the load capacity of the board should be perfect. In this article, we will discuss the engineering approach to choosing from the side of the boat.
There is a common misconception that the heavier the anchor, the better. PVC boats Being overweight creates risks of damage to cylinders and makes landing and disembarkation dangerous, and our goal is to find a middle ground that will ensure a safe parking lot without overloading the vessel.
The main factors affecting the choice of anchor
When calculating the required weight, you need to take into account not only the parameters of the boat itself, but also the external operating conditions. Sailing of the boat It plays a huge role: a high superstructure or an installed awning catches the wind like a sail, significantly increasing the load on the anchor assembly.
The second critical factor is the nature of the bottom of the water body: sandy soil provides better engagement, whereas on clay or rocky bottoms, even a heavy anchor can simply slide across the surface. Other types of bottom require different paw designs.
⚠️ Warning: Never use anchors with sharp protruding elements on inflatable boats without a special protective cover.
In shallow waters (up to 3 meters), the weight of the anchor can be minimal, since the angle of separation from the ground is small. At great depths, not only more weight is required, but also mandatory use. anchor-chain (a small piece of chain between the anchor and the rope) that presses the rope to the bottom.
Formula for calculating the weight of anchors for PVC boats
There is an empirical formula that boatmasters have been using for decades to determine the exact mass, based on the length of the hull of the craft. Ma = k L Bwhere Ma - mass of anchor, L - the length of the boat, B - width, and k - coefficient, depending on the material of the body.
For PVC inflatable boats, the coefficient k If we substitute the average dimensions of the popular three-meter boat (3.0 m long and 1.4 m wide), we get an estimated weight of about 0.21 kg.
In practice, the resulting value is always added safety margin, especially if you plan to catch in windy weather or on the current. the real weight of the anchor for such a boat should be at least 4-5 kg to avoid demolition.less than 3 kg) is justified only on calm lakes without current.
For boats longer than 4 meters, the standard formula may give an understated result, in which case it is better to focus on the match table or increase the weight of the anchor by 20-30%.
Table of correspondence of the length of the boat and the mass of the anchor
To avoid making complex calculations every time, you can use a table that is based on years of experience in small boats, and it is relevant for standard fishing and recreational conditions.
| Boat length (m) | Min. anchor weight (kg) | River. weight (kg) | Type of bottom |
|---|---|---|---|
| 3.0 | 3.0 | 4.0 - 5.0 | Sand, silt |
| 3.0 - 3.6 | 4.0 | 5.0 - 6.0 | Mixed |
| 3.6 - 4.2 | 5.0 | 6.0 - 8.0 | Clay, gravel. |
| 4.2 - 5.0 | 7.0 | 8.0 - 10.0 | Any type |
Note that the column "River weight" is optimal for most situations, and the use of the minimum weight is only permissible as emergency stock or for very short parking lots in perfect weather. Anchor system It should have a safety margin in case of a sharp increase in wind.
Anchor design: What is more important than shape or mass?
The choice between shape and weight is a perpetual dilemma. denforth or Grapple.They have excellent engagement at relatively low weight due to their geometry.
The classic cat's paw (Grapple) is good because it folds compactly and takes up minimal space in the bag of gear, but on the soft and stainy bottom, its paws can simply fall through without providing a reliable support, in which case flat anchors with wide paws work better.
- 🚤 Denforth anchor - ideal for sandy and slurry bottom, quickly burrows, but may not take on stones.
- ⚓ Hall anchor Universal, but requires more mass to work effectively on an inflatable boat.
- 🪨 Cargo cat - good for a rocky bottom, where you need to cling to the ledges, but it does not hold well on hard clay.
Therefore, a 4-pound Denforth often holds better than an 8-pound cast-iron dummy.
Why isn't the anchor holding?
A common cause is the wrong angle of attack: the anchor must fall to the bottom horizontally and then burrow. If the angle of rope is too large, the anchor will drag along the bottom without getting caught, the solution is to use a longer rope or weighting (cartoon).
Materials of manufacture and their effect on weight
The modern market offers anchors of steel, cast iron, aluminum and even lead.stainless-machineThey are durable but corrosive when exposed to salt water for long periods of time if they are not coated.
Cast iron anchors are cheaper, but they're very fragile. When hit by rocks deep in the rocks, the paw of a cast iron anchor can break off, leaving you without an anchor device. Aluminum models are lightweight and don't rust, but their holding power is lower because of their light weight, so they're made more bulky.
⚠️ Warning: Avoid buying silimine anchors, a low-strength material that is often used in cheap Chinese analogues and can collapse under load.
For those who make anchor DIY, the use of lead is a great option. Lead. It has a high density, which allows you to create a compact and heavy load, but it is soft and can deform when hitting rocks, losing its shape.
Proper fastening and length of anchor rope
The weight of the anchor is only half the equation. The second half is the length of the anchor end. There is a golden rule of navigation: the length of the rope should be 3-5 times the depth in the parking lot, only at this angle of tension the anchor works effectively.
For anchoring on an inflatable boat, it is critical to use anchorIt is forbidden to fasten the rope directly to the leer or handle of the balloon, which can lead to the boat turning over with a sharp jerk.
☑️ Checking the anchor system
You also need to make sure you can drop your anchor quickly in an emergency, and if the boat starts dragging you to the doorsteps or under the bridge, you need to be able to do it instantly. anchorUntie the knot or release the pin.
Frequent errors in selection and operation
One of the most common mistakes is the use of concrete blocks, which has a porous structure, absorbs water quickly, gets heavier, but it crumbles easily and stains everything around, and also its shape does not contribute to instillation.
Another mistake is to tie the rope directly to the transom, and if the wind is strong, the boat will turn stern to the wave, and it will start to choke. noseSo the boat will be facing the wave.
- 🚫 Use of rusty chains that stain cylinders and clothing.
- 🚫 The absence of a vertebra, because of which the rope twists and loses strength.
- 🚫 Ignoring the state of the bottom: trying to anchor on the fairway with a strong current.
Remember, the anchor system requires regular maintenance, and after every trip, especially on salt water, the anchor and the rope must be washed with fresh water and dried, and this will prolong the life of the anchor. metallic And prevent the synthetic cable from rotting.
The ideal anchor for a PVC boat is a compromise between weight, paw shape and storage convenience. It is better to take a slightly heavier anchor of the correct shape than a lightweight but useless one on your soil type.
Can you use car cameras or sandbags instead of anchors?
Sandbags are a temporary solution, but the sand tends to wash out through the fabric, and the bag itself quickly becomes unusable. Car cameras do not have enough weight and shape to engage. It is better to buy a specialized folding anchor that will take up a minimum of space.
Which rope is better: nylon or polypropylene?
Nylon (polyamide) is better suited for anchor purposes, and has the ability to stretch under load (up to 15-20%), acting as a shock absorber of surges from the wave. Polypropylene is almost non-stretchable, which creates dangerous dynamic loads on the rim bolt and the anchor itself, although it is cheaper.
Do I need to lubricate the anchor before storage?
Steel and cast iron anchors should be lubricated with a consistent lubricant (for example, Litol-24) or coated with anti-corrosion compounds after drying. Aluminum and stainless steel anchors do not need lubrication, just rinse them with water.