The choice of a swimming aid often begins with an analysis of its design features, among which the shape of the bottom is central. PVC-boatIt's this element of design that determines how a boat will behave on the water, how fast it will get on plane, and how much handling it will provide when it is excited.
Many beginners mistakenly believe that an inflatable floor always means low speed and poor seaworthiness, but modern production technologies allow you to create highly efficient models. Inflatable boats With properly designed bottoms, they can compete with rigid small tonnage housings, and understanding the working principles of hydrodynamic elements will help you avoid mistakes in choosing and operating equipment.
In this article, we will examine in detail the physical meaning of redancing, compare different types of bottoms and find out why the presence of protruding stiffness ribs is so important for safety and comfort on the water. Boat design directly affects fuel consumption and stability of the course, so you can not ignore these nuances.
Physical principle of work of the redeemed
Redan is a transom ledge or rib located at the bottom of the hull of the vessel, and the main purpose of this element is to create a hydrodynamic lift that, when you reach a certain speed, allows the boat to get on plane mode, at which point the hull rises above the water, resting on it only a small part of itself, which significantly reduces the resistance to movement.
When a boat moves, the water flows around the bottom and encounters a redane obstacle, which causes a change in the pressure vector, where the water flows in a dramatic change of direction, creating a zone of high pressure in front of the ledge, and it's this force that pushes the boat upwards. planing This is a critical mode for small-sized vessels with outboard motors, as it allows you to develop high speeds with minimal energy consumption of the engine.
Without the presence of redane or with its incorrect geometry, the boat will constantly “buried” with its nose in the wave or, conversely, experience difficulties with access to working mode. Hydrodynamics It requires precise angle calculations to ensure that the lift is sufficient, but not excessive, which could lead to a loss of stability. Redan also acts as a splash cutter, directing the flow of water to the sides rather than to the cockpit.
⚠️ Attention: Operating a boat with damaged or deformed redane can lead to yaw at high speeds and even tipping. Always check the integrity of the inflatable elements before launching.
Single-bed vs. two-redden models
In the inflatable vessel market, the two most common types of bottom design are those with one redane and two (dual-bed) models, which tend to be simpler and often feature a low-pressure inflatable floor (LDPB) or hard floorboard, and have a redane formed by the junction of the cylinder and the bottom, which creates one line of fracture.
The two-sided boats, often called "catamarans" in the inflatable environment, have two pronounced longitudinal cylinders along the sides and a central tunnel, which creates two redans on the sides. This solution greatly improves the course stability and allows the boat to more easily ascend the wave. Two-redder scheme It is considered more modern and effective for high-speed walks and fishing on large water bodies.
The difference in behavior on the water is noticeable immediately. A single-bottomed boat can be more tilted on turns and require more careful control on the wave. The two-bottomed model, thanks to the tunneling effect, has better stability and is less susceptible to lateral demolition. However, the choice between them depends on the specific tasks: for quiet fishing in calmness, the simple option will suit, and for open water, complex construction is preferable.
- 🚤 Single-sided: Easy to build, lighter, cheaper, but less stable at high speed.
- 🌊 Bi-redder: Excellent seaworthiness, high stability, better to keep the course, but more difficult in drying and packaging.
- ⚖️ Compromise: There are models with a combined bottom, where the redane is reinforced with inserts of plywood or aluminum.
The effect of redane on planing and speed
The efficiency of planing depends on the geometry of the redan. The sharper the angle of attack and the clearer the ledge, the easier it is for a boat to jump out of the water. This is especially true for inflatable boats, since the soft bottom under load can bend, changing the hydrodynamic profile. Underbody rigidity In the area of rentanium is a key factor of speed.
When you get on plane, the contact area with water is reduced by a factor of several. The boat rests on the redan as it slides across the surface. If the redan is too high or is not high enough, the boat will nose-poop, creating a high wave and wasting fuel. transom-angle And the height of the redane allows the motor to operate in the optimal range of revolutions.
The speed of the vessel in planing can be 30-40% higher than in displacement mode at the same engine power, however, the shape of the redane should compensate for these losses, ensuring the maximum possible efficiency of movement.
The height and angle of the redane determine the minimum speed required to get on plane mode, which directly affects fuel consumption.
Underbody materials and construction
In inflatable boats, redane is formed in a variety of ways. In budget models, it's just the connection between the balloon and the inflatable floor. In more advanced versions, it uses thick cloth inserts reinforced with stringers. Stringers - these are longitudinal rigidity elements that do not allow the bottom to bend under the weight of passengers and cargo.
Motor boats often use high-pressure inflatable bottoms (HPDBs), which are very rigid and crisp with thousands of internal bonds that hold the shape, bringing the performance of PVC boats closer to that of fiberglass counterparts, and alternatively, removable plywood or aluminum paioles that create a rigid pad but increase weight and build time.
The material of the redane itself must be highly durable. When mooring to shore or pulling a boat into the sand, this part takes the brunt of the blow. Therefore, manufacturers often use reinforced fabrics with increased density (for example, 1100 g / m2) in areas of high friction.
| Type of design | Rigidity of redeemed | Weight. | Assembly time | Driving performance |
|---|---|---|---|---|
| inflatable floor (NDB) | High. | Medium. | Fast. | Great. |
| Plywood plywood | Very high. | Highly | Long-term | Good ones. |
| Aluminum leaf | Maximum | Medium. | Average | Great. |
| Low-pressure inflatable | Low. | Low. | Instantly. | Satisfactory |
Management and safety on the water
Having a properly working redan is not only a matter of speed, but also of safety. At high speeds, the boat must respond clearly to steering, and if the bottom is soft and the redan floats, the boat can enter an uncontrolled skid. Course stability This is especially important when moving against a wave or in a side wind.
The two-bedged boats with tunnel bottoms have an interesting feature: they are less sensitive to shifting the center of gravity, which means that moving the angler along the cockpit will not cause a sharp roll, and it also better extinguishes the shocks against the wave, making the move softer and more predictable.
However, it is worth considering that high speed and sharp redane require certain skills from the driver. Sharp maneuvers on planing can be dangerous. Always assess the state of the water and do not exceed the recommended engine power for your model.
⚠️ Attention: When driving at high speeds, avoid sharp steering turns. This can cause the inner side of the boat to scoop up water, which can lead to a rollover.
Why is the boat pulling aside?
Often, the boat's drifting aside ( yaw) is not due to a breakdown, but to improper loading. If the center of gravity is shifted sideways or the nose is too up/down, the fluid dynamics are disrupted. Check the load distribution and the tilt angle of the lower unit motor.
Boat bottom maintenance and maintenance
To be able to perform its functions for many years, it needs to be taken care of. After each trip, especially on shallow water or overgrown banks, inspect the bottom for cuts and bruises. Minor damage in the area of the redan can quickly turn into serious tears under water pressure.
Drying is a critical step. If you keep the boat assembled, make sure it is completely dry, otherwise mold may appear inside, which will destroy the adhesive seams. For boats with hard floorboard, it is important to dry the sheets themselves, so that the plywood does not swell and lose shape, disrupting the geometry of the redan.
When storing, try not to create cloth cloth cloth cloth in the bending areas of the redane. PVC material is afraid of prolonged static loads on the folds, which can lead to microcracks.
☑️ Preparation for winter storage
Comparison with rigid housing
Many people wonder: can an inflatable boat with a redan replace a full-fledged boat? In small dimensions (up to 3.5-4 meters), modern PVC models with NDNDL are almost equal to aluminum or plastic counterparts in terms of driving performance, they even benefit from safety, because they do not sink when they penetrate the board.
However, a rigid hull has the advantage of durability of a redane: a metal or fiberglass ledge will never change its shape, whereas an inflatable one can play a little when overloaded, but a PVC boat is easier to transport on the roof of the car and store in the garage.
The choice between them is often dictated by the conditions of use, if you have a trailer and storage space, a rigid body is convenient, if you value mobility and the ability to fold the boat into a backpack, quality. PVC with redane It's the perfect solution.
⚠️ Attention: Do not use abrasive detergents to clean the bottom. They can damage the protective layer of fabric, which will accelerate the wear of redane when in contact with sand and stones.
To extend the service life of the redan, use special protective linings (keli) on cylinders in the nose, if you often moor to unequipped shores.
Frequently Asked Questions (FAQ)
Do I need a redan for a boat under an electric motor?
For electric motors, which typically have slower speeds and do not lead the boat to planing, the presence of pronounced redane is less critical, but it is still useful for improving handling and cutting off splashes, although the requirements for bottom rigidity are lower.
Can I make a redan myself on an old boat?
In theory, you can weld extra tapes or use overlays, but at home, it's almost impossible to recreate the right hydrodynamic shape. It can impair driving performance. It's better to go to a specialized service.
How does the number of passengers affect the work of the rented?
When fully loaded, the boat goes deeper, and the angle of attack of the redan changes, and getting out to planing can be difficult, in which case it helps to adjust the transom angle of the engine or redistribute the load closer to the nose.
Which is better: one big redan or two small ones?
Two redans (two-red circuit) provide better stability and exchange rate stability, especially on the wave wave: one redan is easier to design and lighter, but requires more careful management.