Choosing a swimming aid for shallow rivers, reed-covered lakes or mountain streams often leads to the thought of a water jet propulsion system. PVC jet boats They're a specialized class of inflatable craft that instead of a traditional propeller, uses a water jet that sucks water in and ejects it under pressure, and it allows you to travel only a few centimeters deep, which is not possible for propeller engines.
However, not every inflatable boat is able to withstand the vibration and weight of a water jet engine without risk to the transom. In this article, we will discuss in detail the design features of such vessels, the selection criteria and the nuances of engine installation. PVC material It should be of high density and the floor structure as rigid as possible to ensure the stability of the course and the safety of the crew.
Many water-engineers mistakenly believe that it is enough to simply attach any jet drive to an existing boat, in practice, this leads to deformation of the transom and even rupture of the cylinders due to resonant engine frequencies. The critical parameter is the angle of bottom keeliness in the area of the transom, which must strictly meet the requirements of the jet drive manufacturer for effective water intake. Next, we will look at how to avoid these mistakes.
Design features of boats for water jet engines
The main difference between a boat designed to fit a jet drive is the design of the transom and the floor. Unlike standard models, where the transom can be just a plywood sheet, it requires a reinforced structure that can withstand not only the static load from the weight of the engine, but also dynamic jerks during maneuvers. ferrot with additional slugging and use of marine aluminum or reinforced plywood.
The second important aspect is the rigidity of the bottom, and the water-gun engine creates a specific vibration that is transmitted to the hull, so if the floor bends, the efficiency of the movement will decrease, and the comfort of the crew will decrease to a minimum. NDMA (low pressure inflatable floor) of high quality or with a rigid floorboard floor of moisture-resistant plywood of at least 9 mm thick.
- 🚤 Reinforced transmuner assembly with an angle of keeliness adapted for the water intake.
- ⚓ The presence of a timber around the perimeter to protect cylinders when mooring at unequipped shores.
- 🛡️ Use of PVC fabric with a density of at least 1100 g / sq.m. for increased strength.
It's worth noting that the shape of the cylinders also plays a role: too rounded sides can reduce the stability of the vessel at a sharp set of speeds, which is typical for water jet boats. Manufacturers often make the cylinders more elongated in cross section to ensure better germination and stability of the course, this is especially important when you are driving a vessel at full throttle.
⚠️ Attention: Never use soft-floor boats (without rigid elements) to install powerful water jet engines. Vibration can cause rapid wear of the seams and loss of leakage.
Advantages of water jet propulsion on a PVC boat
Why are inflatable boat owners increasingly looking at jet drives? The main trump card is cross-country. You can walk where the depth is only 15-20 cm, which is absolutely impossible for a propeller motor, and this gives access to the most secluded fishing areas, shallow ducts and rifts of mountain rivers.
Safety is the second most important factor: there are no protruding blades in the jet drive that can injure people in the water or damage underwater vegetation and animals. water-jet It's a non-alternative choice, and it also eliminates the risk of winding grass or nets onto a shaft, which is often the case with screws.
The third aspect is the durability of the propulsion system itself. The water-jet engine is typically water-cooled, which comes from the same source as the propulsion system, which ensures stable operation even over long transitions. But remember, the efficiency of the jet is lower than that of the propeller, so fuel consumption can be higher at the same speed.
- 🌊 The ability to move at a depth of less than 20 cm without the risk of damage to the engine.
- 🐟 Complete safety for fish and no risk of entanglement.
- 🔧 Less exposure to damage from impacts on underwater obstacles.
Choice criteria: what to look for when buying
When choosing a jet drive boat, first of all, look at passport power and the recommended engine length. Not all PVC models are suitable for even light jet drives. Pay attention to the transom marking: if there is a power limit, for example, 5 hp, it is dangerous to put a more powerful unit. It is better to take a boat with a safety margin, designed for engines 9.9-15 hp.
The weight of the boat is another thing that you can't ignore: the water-gun itself is heavier than the power of the screw, and with the tank and fuel, the total weight can be significant. If you plan to often carry the boat alone, consider lighter models, but without losing strength. PVC reinforced It allows you to reduce weight while maintaining strength.
When choosing a boat, be sure to check with the seller whether the factory adaptation of the transom under water jet engines was carried out, since independent revision may deprive you of warranty.
The volume and quantity of cylinders are also important. The water jet boat prefers the model with three or more compartments, which increases the unsinkability and stability. Wide cylinders provide better stability, which is critical for sharp turns characteristic of jet drive control.
| Characterization | Optimal value | Impact on operation |
|---|---|---|
| Tissue density | 1100 g/sqm and above | Resistance to puncture and abrasion |
| Boat length | 3.2 to 4.5 meters | Stability of course and capacity |
| Type of bottom | NDND or plywood peyol | Strength and load distribution |
| Transcent height | Standard (381 mm) or reinforced | Proper installation of the motor |
Installation of a water jet engine: step-by-step instructions
Mounting a jet drive on a PVC boat requires careful preparation and adherence to the technology. A mistake at this stage can cost you a boat or an engine. The first thing you need to do is make sure that the transom will withstand the weight of the unit. If you are in doubt, it is better to strengthen it with additional aluminum linings or replace it with a more powerful one.
The installation process starts with mounting the motor to the transom. Use regular rods, but be sure to put rubber gaskets in to avoid damage to PVC. Then the control system (steer-gas) is connected if it is provided by the design. jet drives often require a special rummel or remote control.
☑️ Check before the first launch
An important step is to check the water intake, make sure that nothing interferes with the flow of water, and the filter mesh is clean. The first run is better done in shallow water, controlling the temperature of the exhaust water (it should be warm, but not hot) and no extraneous noise.
⚠️ Attention: It is strictly forbidden to turn on the water jet engine outside the water or with the water intake closed even for a few seconds, this will lead to instant overheating and destruction of the impeller.
Operation and safety on water
The jet drive boat has its own peculiarities: acceleration is smoother than on a propeller, but maneuverability at low speeds is higher. However, you should remember that the efficiency of taxiing depends on the speed of water flow through the jet drive. When idling, the boat can become almost unmanageable, so always keep a reserve for maneuver.
When driving in shallow water, avoid sudden gas discharges, as this can lead to the absorption of bottom soil, silt or stones into the impeller. If you feel vibration or noise, immediately turn off the engine and conduct a visual inspection. Stones and sand The main enemies of the water jet installation.
What to do if a stone hits the jet drive?
Don't try to start the engine again. Turn the boat over or tilt the transponder to access the water intake. Carefully remove the foreign object with your hand (making sure the motor is off and cooled). If the stone is stuck deep, it may be necessary to remove the grille.
Always carry an emergency stop cord (check), especially if you are alone in the boat. If you fall overboard, the water jet engine will continue to operate and the boat can go in circles or sail away.
jet drive maintenance and care
Regular maintenance prolongs the life of your propulsion system. After each trip, especially if you've been swimming in sandy or slurry areas, you need to flush the cooling system with fresh water. Salts and abrasive particles can quickly disable bearings and seals.
Once a season, remove the jet drive and perform a full impeller inspection, the presence of chipped or cracked blades reduces efficiency and causes vibration, also check the condition of the osteoils and lubricate the shaft according to the instructions of the engine manufacturer. Lubricant It should be special, waterproof.
- 💧 Washing the cooling system with fresh water after each use in salt water.
- 🔩 Check the tightening of the mounting bolts and rods before each trip.
- 🛢️ Replace fuel filters and check hoses for cracks.
Timely washing and lubrication of the shaft is the guarantee that the jet drive will serve you for many years without expensive repairs.
Frequently Asked Questions (FAQ)
Can I install a jet drive on a regular PVC boat?
Technically possible, but it's highly recommended that you don't get a transom boost, because conventional boats are not designed to handle the vibration and weight of the jet drive, which can cause the transom to break, but you'd better choose a model that was originally designed for these engines.
What is the maximum speed of a jet drive boat?
The speed depends on the power of the engine and the length of the boat. On average, a boat with a length of 3.6-4.0 meters with an engine of 9.9-15 hp develops a speed of 25-35 km / h. This is less than the screw counterparts, due to the peculiarities of the jet drive.
Is it difficult to control a jet drive for a beginner?
The jet drive is intuitive, but it's addictive, and the main thing is that you don't have a reverse in the classical sense (a deflector is used) and you have to keep your speed to steer efficiently. You need 1-2 water outlets to adapt.
How much more noise is a jet drive than a screw motor?
The engine itself makes about the same noise, but the jet drive adds the sound of passing water and the impeller. At high revs, the difference is noticeable, but at low speeds the jet drive can even be quieter, because there is no gurgling of the screw.