Plastic outboard motor 9.9: selection, skinning and configuration

The question of choosing a boat for fishing or resting on the water often rests on the search for the perfect balance between cost, capacity and mobility. Plastic outboard motor 9.9 hp This is perhaps the most popular configuration among water-engineers who value the ability to quickly transport on the trunk of a passenger car, and it is the power of 10 horsepower that allows you to confidently display the body for planing even with two passengers on board, remaining within the framework of legislation that does not require GIMS license to drive.

Many beginners mistakenly believe that any body is suitable for such a motor, but the material of manufacture plays a critical role in durability and driving performance. Polypropylene, fiberglass and ABS plastic They behave in a very different way on the water, requiring different approaches to operation and maintenance. A properly selected boat will last decades, becoming a reliable assistant, while saving on material can lead to quick failure or discomfort during fishing.

In this article, we will discuss in detail all aspects of ownership of such a bundle, from the choice of housing material to the nuances of engine installation. the optimal length of the body for the engine 9.9 hp is from 3.6 to 4.2 metersHow to properly sheath the transom to quench the vibrations and what installation errors can cost you expensive repairs, and consider the speed table and the actual cost-effectiveness metrics so that your decision is based on facts, not on marketing promises.

Advantages and features of plastic housing

The main argument in favor of the choice plastic-boat It's completely immune to corrosion, which makes it different from traditional aluminum, and you don't have to worry about rust after the active season, especially if you fish in salt waters or in places with aggressive chemical environments, and plastic doesn't require annual painting, grinding, or difficult conservation for the winter, which saves you time and budget.

However, the material is not the same, and when buying it, it is important to clearly understand the difference between the main types of polymers used in shipbuilding. Fiberglass (Fiberglass) is characterized by high rigidity and excellent smoothness of the surface, which has a positive effect on speed, but it is fragile when hitting stones at high speeds. PolypropyleneOn the contrary, it has a unique shape memory: when it is struck, it is broken, but does not crack, independently restoring geometry, although it has a higher coefficient of friction against water.

The third common option is ABS plasticIt's cheaper to produce, but it's afraid of ultraviolet light, and it can become brittle when exposed to sunlight for a long time, requiring storage under an awning or in a garage. Performance specifications Each material is dictated by its own conditions: if you plan to actively troll at high speeds in open water, fiberglass will be preferable, and for fishing in overgrown reed bays or in shallow water, polypropylene will be more reliable.

⚠️ Attention: When buying a used fiberglass boat, be sure to check the hull for microcracks in the gelcoat. If you hit the side with a coin and sound deaf, you may have a fiberglass layering, which is a critical defect.

Why 9.9 HP is the middle ground

The 9.9 horsepower is not chosen by chance: this is the maximum threshold for driving a boat without a special boatmaster's license in most CIS countries. For many anglers, this is a decisive factor, eliminating the need to take exams in GIMS and register the vessel itself if its length does not exceed certain values. Technically, such engines are often deforested versions of 15-horsepower units, which indicates their high reliability potential.

In terms of dynamics, 9.9 hp engine. It can plane a hull up to 4.5 meters long with one to two passengers, and it provides a comfortable speed of movement on the reservoir in the range of 25-30 km / h, which allows you to quickly get to the fishing point, saving fuel. Weaker engines (2-5 hp) can only slowly move the boat in displacement mode, which in high winds or excitement makes fishing uncomfortable and dangerous.

The weight of the engine is also important: two-stroke models weigh about 20-25 kg, which allows them to be mounted on lightweight plastic boats without critically shifting the center of gravity. Four-stroke counterparts are heavier (about 30-35 kg), but they are quieter, more economical and do not require a benzo-oil mixture. 2T and 4T It depends on your priorities: maximum traction and lightness or quiet running and environmental friendliness.

Criteria for the choice of length and shape of the body

When selecting a boat for a specific engine power, bottom geometry plays no less important role than the material. For a 9.9 hp engine, the body length in the range is considered optimal. 3.6. - 4.2 metresShorter boats (up to 3.2 m) with such an engine will be prone to yawing and spraying into the cockpit, and on longer boats (over 4.5 m), you simply cannot develop full-load glides, wasting fuel.

The shape of the bottom also directly affects the behavior of the vessel on the wave. Kiel-drift They are better at cutting the wave and providing a softer run, but require more power to enter the plane and have less stability in the parking lot. Flatheads or boats with low keel speed go into mode faster, have maximum load capacity and stability, but on choppy water (short wave) can cause discomfort to passengers due to hard impacts on the water.

Pay attention to the design of the transom. For plastic boats, it is critical that the transom is reinforced with a metal profile or stickers, because the vibration from the motor is transmitted to the entire body. A weak transom is the risk of engine tearing off at full speed. bulb or zygomatic splashers that improve the course stability and protect against splashes.

Technical specifications and speed indicators

The actual speed of a plastic boat depends on a variety of factors: load, bottom condition (fouling), type of propeller and even water temperature. However, there are average values that you can target when planning a purchase. Below is a table showing the relationship of speed to the length of the hull and engine type when you load 1-2 people.

Boat length (m)	Motor type	Speed (km/h)	Fuel consumption (L/h)	Mode of traffic
3.6	2T 9.9bhp	28-32	2.5 - 3.0	planing
3.8	4T 9.9bhp	24-27	1.8 - 2.2	planing
4.0	2T 9.9bhp	26-29	3.0 - 3.5	planing
4.2	4T 9.9bhp	22-25	2.0 - 2.5	planing
3.6	Any 9.9bhp.	6-8	0.8 - 1.0	Water-displacement

As you can see from the data, two-stroke They're going to get a speed gain of about 10 to 15 percent, which is pretty noticeable on the water, but four-strokes are going to get a lot more efficiency in long-distance and trolling mode, and it's important to understand that the stated top speed is often at the rotor's limit, which is not always effective for everyday use.

Rotor selection is a separate science. For heavy boats or frequent full-load fishing, it makes sense to install a screw with a smaller pitch. This will allow the engine to unwind more easily to operating speeds, improve acceleration dynamics, although the maximum speed may decrease slightly. Conversely, for light walks for 1-2 people, you can experiment with propellers of increased pitch.

Tranza skin: combating vibration and noise

One of the major problems with plastic boats, especially fiberglass boats, is the high level of noise and vibration transmitted from the running motor through a trawler to the entire body, which not only tires the angler, but can scare fish away within a radius of several tens of meters. transmolina and internal vibration isolation are a mandatory stage of tuning immediately after purchase.

For effective noise reduction, bitumen-based materials with an aluminum layer, such as Vibrosplast or bimastThe process of skinning begins with degreasing the surface of the transom, both outside and inside the cockpit, the material is heated with a building hair dryer and rolled tightly to exclude air bubbles, special attention should be paid to the places where the motor and zygomatic area are attached.

• 🛠️ First layer paste the vibroisolating material on the inside of the transom, covering at least 70% of the area.
• 🛠️ Use foamed polyethylene with foil (for example, splendor) for additional heat and noise insulation.
• 🛠️ Be sure to treat the rundoos and bottom in the nose, as they also work as resonators.

If your boat has a removable transom or hinged, make sure that the pads between the metal elements and the plastic are intact. Rubber dampers tan and lose their properties over time, they need to be replaced periodically. Quality insulation can reduce the noise level in the cockpit by 10-15 dB, which makes a noisy trip into a comfortable walk.

Installation and configuration of the outboard motor

Properly mounting the motor on the transom is a guarantee of safety and efficiency of the boat. The engine must be fixed strictly in the center of the transmunist, and its lower unit (leg) must be in the diametrical plane of the vessel. The distortion of even a few degrees will lead to the boat's sideways at full speed and uneven wear of the gearbox. Use high-quality bolts with growers or special rods, if the design allows.

The critical parameter is the height of the anti-cavitation plate, which must be parallel to the conventional bottom line or be buried (10-20 mm) relative to the bottom plane. If the motor is raised too high, air suction and thrust loss will begin; if it is lowered too low, water resistance will increase and handling will deteriorate. Adjustment is done by rearranging washers on the fasteners or changing the position of the rod.

Sequence of installation check:
Set the motor on the transom and tighten the mounts.
2. lower the lower unit into the water (or use the level on the anti-cavitation stove).
3. Check the parallelity of the keel line plate.
4. Start the motor and check the water jets from the control holes.
5. On the move to assess the absence of cavitation at full gas.

Also, you should take care of safety. Be sure to use a safety cable (check), which should be attached to the driver's clothes. In a plastic boat where the sides are slippery, the risk of falling overboard in a sharp maneuver is higher than in a keel metal boat with keys. Security Always be the number one priority.

⚠️ Attention: Never run the engine out of water or without a water cooling system ("ears" or barrels) attached unless designed. Even short-term "dry" operation can disable the pump and omentums, leading to costly repairs.

Maintenance and preparation for winter

Plastic requires less maintenance than metal, but that doesn't mean you can just throw a boat out in the open for the winter. Ultraviolet breaks down the structure of the polymers, making them fragile. plastic-boat It should be carried out either indoors or under a dense, opaque awning. Before setting for wintering, you must thoroughly wash the case, removing all algae and silt that may contain aggressive substances.

The motor also requires preparation. If you use a two-stroke, be sure to produce the remaining fuel in the carburetor or preserve the system with a special oil. For four-strokes, it is important to replace the oil in the gearbox and engine if the T. T. deadline is reached. Lubricate all the grease points of lower unit to displace moisture and prevent corrosion of bearings and needle joints.

• ⚓ Remove the battery and charge it in a warm room, checking the electrolyte level once a month.
• ⚓ Treat the metal parts of the motor (except for the lower unit inside the water) with preservative lubricant.
• ⚓ The boat is better stored upside down or on special kilblocks to avoid deformation of the hull under its own weight.

Do I need to drain the oil from the gearbox for the winter?

If the gearbox is good, the oil should not be drained, but many experts recommend replacing the oil in the gearbox before winter, as old oil can contain wear products and microscopic moisture, which can cause the gears to corrosion from the inside during the winter.

Frequently Asked Questions (FAQ)

Can a plastic boat with a length of 3.5 meters to put the engine 9.9 hp?

Technically, you can, if the transom can withstand this power (usually up to 10-12 hp for this length). However, at full gas, such a bundle can be unstable, especially on the wave. The boat will be prone to yaw, and the plane will occur with a sharp roll. For a length of 3.5 m, the optimal motor is considered to be 5-8 hp, which will ensure safer and more comfortable operation.

Which screw is better to choose for fishing with cargo: three-bladed or four-bladed?

For fishing, especially when full loaded (equipment, tent, sonar, passengers), a four-blade propeller is often preferred. It provides better traction at low speeds, puts the boat on the plane faster and allows you to move more confidently at low speeds (trolling). A three-blade propeller will give a greater maximum speed on a light vessel, but the thrust failures when loading will be more noticeable.

Do I need to register a plastic boat in GIMS?

Registration is required if the weight of the outfit exceeds 200 kg OR the engine power is more than 8 kW (about 10.88 hp). Since the 9.9 hp engine formally fits into the power limit (8 kW ≈ 10.88 hp, but 9.9 hp = 7.28 kW), the weight of the boat itself with the equipment becomes the decisive factor. Light plastic boats up to 3.5-3.8 meters often weigh less than 200 kg, which avoids registration.

How to wash a plastic boat so as not to damage the material?

Use conventional automotive chemicals or special means for washing boats. Avoid aggressive solvents (acetone, gasoline) and abrasive brushes that can scratch gelcoat or plastic. Use soft rags and warm soapy water to remove persistent contaminants (oil, fuel). After washing, it is advisable to treat the case with a UV filter polyrene.