Low-pressure inflatable boats (LBBBs) have become the standard of comfort on the water, but their operation requires strict adherence to training technology. structural rigidity The only way to create a hull is by keeping the air pressure right, and mistakes on the shore often turn into problems on the water: a pumped tank can burst from the sun, and a poor pumped peyol will make the boat unmanageable.
The process of filling with air seems simple only at first glance, but this is where most of the causes of premature wear and tear lie. PVC materialsThe owner must clearly understand the difference between the operating pressure in cylinders and in floorboards, and also take into account the influence of ambient temperature. Ignoring temperature expansion of air is the main cause of ruptures of seams on hot daysWe'll take each stage apart so your boat can last for decades.
You'll need a good pump to start with, and it can be a foot frog or a battery-powered electric compressor, and the main requirement is a pressure gauge, without which pressure control is impossible, and you don't have to rely on the "feeling" of a finger, because the subjective feeling of hardness is often deceptive and depends on the thickness of the material and the temperature of the hands.
Preparation of the site and initial inspection of the boat
Before you plug in the pump hose, you need to roll the vessel around correctly. Choose a flat area cleared of sharp stones, branches, cigarette butts and construction debris. Even a small pebble under the bottom when inflated will create a stress point that will lead to abrasion of the fabric or puncture. Ideally, conduct training on grass, sand or a special protective mat.
Carefully inspect the valves. Make sure they are clean, dry and have no sand crumb inside. Sand caught in threads or silicone seals breaks the tightness and can damage the pumping "petal" mechanism. If the boat was stored folded, let it straighten naturally for 10-15 minutes, especially during the cold season when the material becomes rigid.
In cold weather (+5 ° C and below), preheat the cylinders with a hairdryer or bring the boat into a warm room for 20 minutes - cold PVC with a sharp inflatation can give microcracks in the places of folds.
Check the kit. Make sure you have a refit, spare valves (just in case) and keys to maintain them. Sometimes during storage, sealing gums can dry out, and they're better treated with silicone grease beforehand. This will take a minute, but save you time on the water.
Sequence of pumping cylinders and floorboard
There is a golden rule of using NDNDM: cylinders are always pumped first, and only after they reach a certain shape, the paiola (inflatable floor), if you start with paiola, they will rest in even soft sides, which will lead to skewed design and uneven distribution of loads, at worst this causes deformation of bulkheads inside the cylinders.
Pump the cylinders alternately or in parallel if you have a two-threaded compressor, bring the pressure in them to 70-80% of normal (about 0.15-0.2 atm). At this stage, the boat should acquire its geometry, but remain soft enough to touch, this is necessary in order to straighten all the folds of the material and level the bulkheads inside.
☑️ Pumping procedure
After the primary shape of the cylinders, go to the bottom. Paiola NDND is a complex engineering element, consisting of thousands of vertical strands, and it is the high pressure in them (usually 0.6-0.8 atm, sometimes up to 1.0 atm for rigid models) that turns a soft pillow into a hard floor. Don't be afraid to rock the bottom hard, it is designed for serious loads.
When the floorboards are inflated and hard, go back to the balloon, and now you need to bring their pressure to its working value (usually 0.2-0.25 atm). Note that the cylinders should not be stone. Their job is to cushion the shocks against the wave, so the excess pressure here is harmful to comfort and safety.
Working pressure: table and temperature nuances
Understanding the physics of gases is critical for the owner of a PVC boat. Gay-Lussac's law states that when heated, the volume of gas increases, and when the volume is constant (in an inflated cylinder) the pressure increases. Pumped in a garage at +15 ° C, a boat, when exposed to the sun at +30 ° C, can increase the internal pressure by 15-20%, which creates the risk of rupturing the seams.
Below is a table of indicative pressure values for different structural elements. Always check the manufacturer's instructions for your particular model, as the density of the fabric and the design may vary.
| Element of the boat | Min. pressure (atm/psi) | Max. pressure (atm/psi) | Features |
|---|---|---|---|
| Cylinders (board) | 0.2 (3 psi) | 0.25 (3.6 psi) | Must spring on the press. |
| Paiola (bottom) | 0.6 (9 psi) | 0.9 (13 psi) | Must be as hard as a board |
| Keel (if any) | 0.2 (3 psi) | 0.3 (4.3 psi) | Provides course stability |
| Trans valve | 0.2 (3 psi) | 0.25 (3.6 psi) | Control after installation of the motor |
Why can't you pump cylinders up to 0.5 atm?
Some newcomers try to make the boards stiff by pumping them like a bottom. This is a mistake. High pressure cylinders have a different design. The pumped-up NDNDB side loses its cushioning, the boat becomes rigid and unstable on the wave, and the seams receive a critical tear load when hitting the water.
If you pump a boat indoors or in the shade, and you plan to go out in the open sun, don't get the pressure to the maximum right away. Leave a supply of 0.05-0.1 atm. On the water, under the influence of sunlight and heat from the water, the pressure will rise to the desired level. Monitor the condition of the cylinders in the first 30 minutes of exposure to the sun - if they become too tight, blow the excess air through the valve.
Use of electric and foot pumps
The choice of pumping equipment depends on the operating conditions. Foot pumps ("frogs", "accordances") are reliable, do not require electricity and allow you to feel the resistance of air. However, they pump BND, especially volumetric (3.6-4.5 meters), physically difficult and long, it is a great option for pumping on the water or for small boats.
Electric compressors speed things up a lot. Modern models often have automatic pressure shutdowns. This is convenient, but requires a check on the built-in pressure gauge. Cheap Chinese compressors often lie, showing 0.2 atm when the reality is already 0.4. Always double-check the result with a mechanical pressure gauge.
When using an electric pump, keep an eye on the temperature of the device itself. Compressors are not designed to run for more than 15-20 minutes continuously. Let them cool down, otherwise the engine may burn down in the middle of the process. For large boats, it is ideal to have a two-step scheme: quick turbine pumping to the shape and precise fine-tuning with the piston part or manually.
It's important to connect the hose to the valve properly. Air Marine or Bravo If the joint is leaky, the compressor will run idle, overheating and not creating the desired flow. Use the adapters that come with the kit, and make sure that they do not get lost.
Typical errors in pumping a NDND boat
One of the most common mistakes is uneven pumping, where owners can pump one side and leave the other side weak, which causes the boat to roll, which is especially dangerous when installing an outboard motor, and skewed transom plates put uneven loads on the transom, which can cause it to tear off or deform when glides.
The second mistake is ignoring the valves after the pump is pumped. After the pump is detached, make sure that the valve is closed. In some models (with a screw mechanism), you need to twist the center part to the end. An unwound valve will slowly poison the air, and after an hour on the water you will get a soft boat that is poorly controlled.
⚠️ Attention: Never leave a fully pumped boat in direct sunlight unattended on shore, and the pressure inside can grow so much that the valve will force the air to blow out, or, in the worst case, the seam will rupture.
It's also a mistake to try to fix the floorboard dent by increasing the pressure above normal. If you have a load or seat pit at the bottom, adding pressure won't help, it just stretches the fabric. The dents on the floorboards of NDNDM are normal, they straighten themselves when you get on the boat or level the load.
Valve maintenance and storage
The durability of your boat depends on the condition of the valve group. After every fishing or walk, before packing, the boat must be blown away. This must be done carefully, starting with the floorboard. Open the valves and let the air go out on its own, do not press the cylinders with your knee to squeeze out the residues - this creates reverse pressure and can damage the internal partitions.
When packing, try to fold the boat so that the folding places do not match each time the flexing places of the valves. The valve is rigid elements, and if they constantly fall into the same fold, the material around them will quickly rub. Change the addition circuit from time to time.
Compliance with the pumping sequence (first of the side, then the bottom) and pressure control taking into account temperature is the key to the long service of the NDND boat and your safety on the water.
Regularly lubricate the movable parts of the valves with silicone lubrication. This will prevent the rubber from drying out and the mechanism from jamming. If you notice that the valve has started to "tear" even when closed, don't ignore this. Often, it is enough to simply clean it of a grain of sand or replace a sealing ring, which costs a penny compared to the risk of losing a boat on the water.
Can I pump a NDND boat with a truck compressor?
You can, but with great care. These compressors are extremely pressure-intensive (8-10 atm) and have high performance. The risk of pumping and tearing the boat in seconds is very high. Be sure to use a gearbox or swing short "spit" with constant pressure gauge control. It is better to use specialized boat compressors with a pressure limiter.
Why does the boat become soft on the water, even though it was solid on the shore?
This is a cooling effect. Water is usually colder than air, especially at depths. When in contact with cold water, the air inside the cylinders shrinks and the pressure drops. So always pump the boat afloat after it has been lying on the water for 10-15 minutes.
How to store the boat in the off-season: inflated or deflated form?
The best storage option is half-blown (pressure about 0.05-0.1 atm) in straightened form, suspended or lying on a flat surface. This relieves tension from the fabric and seams, but retains shape. Storing completely deflated in tight twisting for years leads to crumbs, and storing in stone the inflated leads to stretching the material.
What to do if the pressure gauge is broken and you need to pump?
Use the hardness method. The cylinders should be elastic, like a well-inflated car camera (but softer). The piolas should be hard, like the floor in the room. If you press a finger with force, the surface is broken by more than 1-2 cm, there is not enough pressure. If the finger does not press at all, perhaps too much pressure.
⚠️ Attention: When transporting on the roof of the car in an inflated form (on a trailer or soft arcs), be sure to reduce the pressure in the cylinders to 0.15 atm. At speed, the oncoming airflow and heating from friction can critically increase the pressure inside.