The choice of a swimmer always begins with the definition of its purpose, and the key parameter here is the design of the bottom. It depends on this detail whether you can comfortably move along the inflated bottom, how the boat will behave on the wave and how fast the outboard motor can develop. For many aqueous motorists, the question "boat with which bottom is better" is the starting point when buying, because there is no universal solution.
The modern market offers several technological solutions, each of which has its own advantages in specific operating conditions: inflatable floors of NDND provide maximum comfort and safety, sleigh options give a gain in speed, and hard plywood floor turns an inflatable boat into a full-fledged boat. Understanding the difference between these types will allow you to not overpay for unnecessary functions and get the vessel that is ideal for your tasks.
In this article, we'll take a look at all the types of bottoms that exist, and analyze their impact on performance, weight and durability, and you'll learn why every gram of weight is important for some anglers, and for others, the ability to stand up fully without the risk of damaging the balloon is critical. kielson And why it's important for seaworthiness, and we'll figure out which option is best for you.
Typology of bottoms: from simple inflatable to rigid
Structurally, all bottoms of PVC boats can be divided into three main groups: fully inflatable, combined (using removable or insert elements) and rigid. Low pressure inflatable floor (LDPB) It's a single structure where the floor is part of the housing, and it provides excellent thermal insulation and cushioning, which is especially important for long-term exposure to water.
The second type is slate boats, which are plywood or aluminum ink sections that fit inside an inflated hull, often called "books" because of the way they fold, and the third option is rigid back bottom boats (RIBs), where the supporting structure is a fiberglass or aluminum hull, and the sides are made of PVC.
Each type has its own physical properties that affect the hydrodynamics The inflatable floor creates the greatest resistance to water because of its softness and deflection under load. The slurry bottom already holds the shape better, but has joints between sections. The hard bottom provides perfect streamlinedness, allowing the boat to plane with minimal engine power.
⚠️ Attention: Never use an inflatable floor boat (BBB) under motors above the manufacturer's recommended power. The soft bottom at high speeds can deform (the "sailing effect"), resulting in loss of handling and even overturning the vessel.
Low Pressure inflatable floor (LDPB): Comfort vs Speed
Low-pressure inflatable boats are often chosen by tourists and anglers who value comfort over speed, and the main advantage is that there are no hard elements, which makes assembly and disassembly as quick as possible, you don't have to wait until the dirt on the sleighs dry, or spend time laying heavy plywood sheets.
These models have excellent seaworthiness Soft floors absorb shocks, which reduces leg and back fatigue during long periods of parking, and NDND provides better thermal insulation: sitting on a bottom without a mat, you hardly feel the cold from the water, which is critical in the off-season.
But there's a downside to this, because the inflatable floor is bending under the weight of the passengers, creating a hammock effect, which increases the area of contact with the water and, as a result, the resistance, the plane speed on these boats comes later, and the fuel consumption will be higher compared to hard bottoms of the same power.
- 🌊 Ideal for calm water, lakes and small rivers with slow currents.
- 🎣 The best choice for sitting fishing is when stability and comfort are important, not the speed of the transition.
- 🏕️ A great option for family holidays and swimming due to the soft surface, safe for children.
- 🎒 Maximum light and compact in assembled form, which is convenient for transportation in the trunk of a passenger car.
Air Deck Technology
The secret to NDNDM is to use thousands of vertical strands (Drop-stitch) that connect the top and bottom shells of the floor, which allows you to pump the floor to a pressure of 0.6-1.0 atm, making it rigid, but retains cushioning properties.
The slate bottom: the golden mean for the fisherman
The slate bottom is a compromise solution that combines the mobility of an inflatable boat and the stiffness required for confident glides. Sleighs are usually made of water-resistant plywood 9-12 mm thick or light aluminum. They are placed inside the cylinders on special stringers (guides).
The main advantage of this solution is that you can get a fairly rigid footpad, you can stand on the sleigh with confidence, which is important for spinners who make active throws, the rigidity of the design allows you to keep the course better and use the power of the motor more efficiently, and when you install it correctly, the sleighs create a flat plane, minimizing the resistance of water.
However, the weight of such a boat will be much higher than that of the model with NDND. Plywood absorbs moisture, so the sleigh requires careful drying after each operation, otherwise they can be layered or covered with mold. Aluminum sleigh is lighter and not afraid of water, but they are noisier and colder to the touch.
To make the sleigh last longer, treat their ends with moisture-proof wood or special yacht varnish once a season, which will prevent plywood from swelling and stratification.
An important element of the construction of the slate floor is kielsonIt's a rigid pad running along the diametrical plane of the boat over the sleighs. Kielson gives the bottom the profile necessary for sustainable plane and improved course stability. Without the keelson, the boat can scour side to side even with the slightest ripples.
Hard inscribed bottom (Rib concept) and aluminum boats
For those who prioritize speed, load capacity and durability, there are boats with a rigid indented bottom or a fully rigid hull. In the PVC segment, this is often referred to as the "Rib Concept," where the bottom is a single sheet of plywood or fiberglass inserted inside. In the metal boat segment, the bottom is an integral part of the hull.
These designs allow for more powerful motors and higher speeds, and the hard bottom does not deform under load, providing a stable geometry of the hull, which is especially important when you go on a wave: the boat does not "fall down", but cuts through the water, which increases the safety and comfort of passengers.
Aluminum boats (Kazanskies, salutes and their modern counterparts) have their own specifications. Aluminum is strong but susceptible to electrochemical corrosion, especially in salt water. However, modern alloys and anodic oxidation minimize these risks. The main advantage of metal is its almost non-fire life when properly maintained.
| Type of bottom | Weight (average) | Gleaming speed | Comfort. | Durability |
|---|---|---|---|---|
| Inflatable (NPD) | Low. | Low. | Highly | Medium |
| Slate (Phanera) | Medium. | Medium | Medium. | Medium (depending on care) |
| Slate (Aluminum) | Medium/Low | Medium/High | Low (cold) | High. |
| Rigid (RIB/PVC) | Highly | High. | Low (mat required) | High. |
Impact of bottom design on driving performance
Do not underestimate the influence of the type of bottom on the behavior of the boat on the water. Hydrodynamic resistance The soft inflatable floor, under pressure from water and passengers, forms a cavity that acts as an anchor, inhibiting acceleration, and the hard bottom retains its predetermined shape, allowing water to flow freely around the hull.
Also important is the issue of handling: boats with a hard bottom or a quality keelson are better at steering, especially in lateral wind or excitement. On a soft bottom, the stability is lower, which requires more frequent operation with a tiller or gas control pedals, which can tire the operator when long hops.
Another aspect is noise. The inflatable floor is almost silent, which is important for hunting or careful fishing. Aluminum sleighs or metal casings can rattle on the wave, unless you use special anti-slip and noise-absorbing coatings. The vibration from the motor is also transmitted to the hard bottom more strongly than to the inflatable one.
⚠️ Attention: When operating a boat with a slate bottom, make sure that there are no gaps between the sections of the sleigh. Sharp objects or sand falling into the gaps can lead to wiping the inside of the cylinder and leakage.
Practical advice on selection and operation
When you're choosing a boat, ask yourself, how often do I pick it up and disassemble it? If you plan to go down once a week from a prepared parking lot, then weight and dimensions are not so important, and you can have a hard bottom. If you need a boat for spontaneous rides on a passenger car, NDNDM will be more convenient.
Pay attention to the quality of the materials. For sleighs, it is better to choose aviation plywood with high moisture resistance or anodized aluminum. For the inflatable floor, it is important to have a dense reinforced material that can hold the shape. Don't skimp on this element, because it is impossible to replace it in the field.
- 🛠️ Regularly check the condition of the valves and seams, especially in the areas where the floor is connected to the cylinders.
- 🧼 Wash the boat with fresh water after each exit, especially if you have been swimming in salt water or dirty water.
- ☀️ Keep the boat in a dry, cool place, protected from direct sunlight to avoid PVC degradation.
- 🔧 Always carry a remix that matches the material of your boat (PVC or aluminum/plywood).
☑️ Testing season readiness
Comparative analysis: what to choose for different tasks
For fishing alone or together on small bodies of water, a compact inflatable floor boat is ideal. It is light, quiet and comfortable. For trophy fishing in large reservoirs, where long-distance and wave resistance are important, consider models with a slate bottom and a powerful keelson.
If your goal is active water tourism with overnight stays and plenty of equipment, a hard bottom (RIB or indented plywood) will provide the necessary load capacity and speed. Metal boats are good for rocky rivers where there is a high risk of damaging the soft bottom, but they require a trailer to transport.
Ultimately, the "best" bottom is the one that suits your skating style: Don't chase maximum stiffness if you like to lie on your nose with a fishing rod, but don't choose a soft bottom if you plan to go over 30 km/h.
There is no perfect bottom for all conditions: NDND is the king of comfort, slate is the station wagon, hard bottom is the choice of high-speed maniacs and freight transport.
Frequently Asked Questions (FAQ)
Can I put a powerful motor on a boat with an inflatable floor?
Technically, if the passport power of the boat allows. However, the efficiency will be low: the boat will not go well for planing, and the soft bottom will “dig” water. For powerful engines (from 15 hp), a hard or slate bottom with a keelson is strongly recommended.
How often should the inflatable floor be pumped?
The pressure in the cylinders and the bottom depends on the temperature. When you go out to the sun, the air expands and the pressure increases, and in cold water it drops. Check the pressure before each outlet and after prolonged parking. Normal working pressure is usually 0.2-0.25 atm for cylinders and up to 1.0 atm for the NDNDND floor (check the instructions).
Which is better: plywood sludge or aluminum?
Plywood is cheaper, warmer to the touch and less noisy, but dreads moisture and requires drying. Aluminum is lighter, timeless, not afraid of water, but it is cold, noisy and more expensive. The choice depends on your budget and the boat's storage conditions.
Can I replace the inflatable floor with a hard one in my boat?
Most of the time, no. The design of the NDND boats and slate boats is different, hard bottom cylinders have special pockets and stringers, and trying to insert a hard bottom into a boat that is not designed to do this can cause the cylinders to deform and break the seams.