Choosing the right engine for a PVC boat is a fundamental step in determining not only your speed on the water, but also your safety, as well as the durability of the boat itself. Miscalculating thrust or ignoring the design features of an inflatable boat can turn a pleasant walk into a dangerous adventure with the risk of puncture or loss of control. Today, the market offers dozens of models, each of which has unique specifications that require careful study before buying.
Inflatable boat owners often face a dilemma: take a motor with a reserve of power for planing with full load or limit yourself to an economical option for a quiet fishing. transom plateThe weight of the engine and the type of screw play no less a role here than the formal one. horsepowerLet's figure out how to find the perfect balance between the specifications of the boat and the capabilities of the engine, so that you can enjoy each step on the water.
Understanding the physics of the process will help avoid common mistakes, such as engine overheating or transom collapse. transfer ratio The gearbox and the diameter of the screw allow you to unlock the potential of even the most powerful unit. In this article, we will look in detail at all aspects of the selection of the power plant.
Criteria for the power selection and type of engine
The first thing you need to start planning a purchase is to determine the maximum power your boat can sustain, and the manufacturer always lists this parameter in the technical documentation, and exceed it. forbiddenExceeding the recommended power causes an excessive load on the transom, which in dynamic wave conditions can cause it to be detached or deformed at the anchorages.
However, focusing only on the "maximum" is also not always correct. For small two-seater boats up to 3 meters in length, electric motors or gasoline units with a capacity of up to 5 hp are often the best solution. plane-mode It's a one-person model, but it's still light and economical, and more powerful models, like 9.9 or 15 hp, require an inflatable keel and a rigid solder floor to compensate for the hydrodynamic drag.
When choosing between two-stroke and four-stroke engines, it is important to consider the nature of operation: Two-strokes are lighter, easier to transport (you can carry on the side), and cheaper to maintain, but they consume more fuel and oil. Four-stroke engines quieter, more economical and more environmentally friendly, but their weight can be critical for light PVC boats, shifting the center of gravity and impairing driving performance.
⚠️ Warning: Never install an engine above the maximum permitted power specified in the boat's passport, which can cause the transom plate to collapse instantly and the boat to sink at full speed.
Also worth paying attention to the length of the lower unit. For high-sided inflatable boats, the standard length S (381 mm) may not be enough, and a modification of the L (508 mm) will be required so that the screw does not capture air and create a cavitation funnel. traction And it protects the propeller from damage.
Gasoline vs. Electric: Comparison of Technology
The debate over which engine is best suited for a PVC boat has been going on for years, and gasoline engines are the only alternative for long distances and high speeds, they provide high power density and autonomy, allowing you to travel tens of kilometers without refueling. petrol-engine It is the only rational choice.
Electric motors are the choice for quiet fishing, eco-tourism and cruising in noise-restricted areas. Lack of exhaust gas and low vibration make them ideal for fishing, where silence is important. Modern lithium-ion batteries are lighter and capacious, but still lose to gasoline in energy consumption per unit weight. Electric motor will not allow to develop high speed, but will provide stable traction at low speeds for several hours.
Let’s compare the main specifications of these two types of engines for a better understanding:
| Characterization | Gasoline engine | Electric motor |
|---|---|---|
| Maximum speed | High (up to 40+ km/h) | Low (up to 10-15 km/h) |
| Noise level | High (requires hearing protection) | Minimum (silent) |
| Weight (including fuel/AKB) | Medium/High | Depends on the capacity of the BAC |
| Service | Replacement of oil, candles, filters | Charging, terminal control |
| Environmental friendliness | Low (exhaust gases) | High (zero emissions) |
It's important to note that electric motors require careful calculation of battery capacity, and if gasoline can be added to a canister, a discharged battery away from the outlet will turn your boat into a stationary object. Depth of discharge The traction battery is a critical parameter that cannot be ignored when planning a route.
transom plate: the basis of security
Installation of the engine on the PVC boat is impossible without a reliable transom plate. It is a rigid structure, usually made of moisture-resistant plywood or composite materials, which takes the entire load from the operation of the engine. The quality of the transom production directly affects the boat's handling. If the plate is "playing" or deformed under load, the screw will constantly change the angle of attack, which will lead to yawing of the vessel and loss of speed.
When installing, you must make sure that the transom plate is installed strictly vertically or with a minimum different recommended by the manufacturer. transom-mountingThe use of additional reinforcing linings made of aluminum or fiberglass significantly extends the life of the plywood, protecting it from delamination under the influence of moisture and vibration.
The fastening of the motor itself to the transom must be carried out through special rods that evenly press the engine to the surface. It is unacceptable to attach the motor to only one point or use homemade clamps of dubious strength. Vibration.The slurry that occurs during the operation of the engine is able to quickly shake any weak connections.
☑️ Checking the readiness of the transan to install the motor
For boats with an inflatable transcent (when the back of the boat itself is a cylinder), the use of a rigid insert is mandatory. The soft transom is not able to perceive the reactive propeller thrust, and trying to fix the motor directly on the cylinder will lead to its deformation and potential tearing of the material.
Rolling screws: selection and configuration
The propeller is the legs of your engine, and it's the parameters that determine whether the engine can get to the optimum speed. The main specifications of the propeller are the diameter and pitch. The screw's pitch determines how far the boat will go in one revolution of the propeller under ideal conditions. Too much stride will prevent the engine from spinning to working speed, causing detonation and overheating, and too little will lead to overtorsion and fuel consumption.
PVC boats that have high drag often require propellers with a reduced pitch compared to keel boats of the same power, which allows faster sleeve. The propeller material is also important: aluminum propellers are cheaper and easier to handle when hit, but stainless steel It provides better efficiency and durability, although it costs more.
When selecting a screw, you need to focus on the tachometer readings. If the engine does not gain the upper limit of the recommended range of revolutions (indicated in the manual), the screw pitch should be reduced. If the revolutions exceed the norm, increase the pitch. A correctly selected screw ensures maximum speed and minimum fuel consumption.
Service and preparation for the season
The PVC outboard motor is more aggressive than the outboard motor because of its proximity to water and the possibility of splashes entering the air filter. Regular maintenance is the key to the long life of the unit. Before each season, you need to check the condition of the spark plug, clean the carburetor from possible deposits and change the fuel filter. Special attention should be paid to the cooling system: make sure that the control stream of water is stable, which indicates the work impeller (pumps)
When stored in winter, the engine must be preserved. For two-stroke engines, this means generating fuel from the carburetor and adding conservation oil to the cylinder. Four-stroke engines require changing the oil in the crankcase before wintering, since the used oil contains acids that can damage engine parts during downtime.
Transporting the engine also requires compliance with the rules. If you are carrying a four-stroke, it can only be transported in the working position or strictly on a certain side (usually left, but it is better to specify in the instructions) so that oil does not get into the cylinder. Two-stroke motors in this regard are less demanding, but protection from dust and moisture when transported in the trunk of the car is mandatory for all types.
⚠️ Warning: After operating in salt water, be sure to rinse the engine with fresh water outside and let it work for a few minutes in a fresh water tank to flush the salt out of the cooling system.
Safety and operating rules
Operating an outboard motor requires strict safety regulations. check-line The kill switch is a requirement, and this cable is attached to the engine at one end and the driver's clothes or wrist at the other end, and if a person falls overboard, the cable is pulled out, and the engine dies, preventing the boat from going around in a circle and possibly hitting a person.
It is also important to monitor engine temperature. Many modern models have overheating indicators, but you should not rely on them alone. Periodically check the temperature with your hand (caution!) in the area of the thermostat. Overheating can be caused not only by a malfunction of the pump, but also by floating algae that clogged the water intake.
Never run the engine out of water without connecting to a water cooling system (barrel or plumbing). Dry work, even for a few seconds, can cause the impeller pump to melt and the piston group to overheat. Dry launch. allow only for a very short time to check the spark or pump fuel.
Frequently Asked Questions (FAQ)
Can I put a motor more powerful than the factory recommends if I am alone in a boat?
No, it's not allowed by safety regulations and technical regulations, because the strength of the transom and inflatable tubes is designed to be loaded, and even if you exceed the power of one person, you risk breaking the structure on the wave due to dynamic loads.
Which gasoline is best used for a two-stroke engine?
Use only fresh AI-92 or AI-95 gasoline (as instructed) with the octane number recommended by the manufacturer. The fuel should not be stored for more than 2-3 months, as it loses its properties and forms a resinous sludge that clogs the carburetor.
Why does the engine stop at high speeds?
The most likely cause is air pumping into the fuel system or a fuel tank/filter clogging, and the problem may be spark plug or carburetor tuning disruption. Check the tightness of the fuel hoses.
Do I need to smear the lower unit shaft before every trip?
The shaft of lower unit is lubricated with a special water-resistant lubricant for each removal of the screw for cleaning or preservation, before each trip, a visual inspection is enough, if the oil seals are working.
How often should you change the oil in the gearbox?
The oil in the gearbox is recommended to be changed once a season or after every 100 hours of operation. Darkening of the oil or the appearance of an emulsion (light coffee color) indicates water intake and requires immediate replacement of the omentums.