Finding the perfect solution for navigating overgrown rivers and shallow channels often leads to one particular detail. long-dadewoodIt's not just a marketing ploy, it's a design feature that allows you to raise the level of the market. propeller For anglers and hunters whose routes pass through dense vegetation, this option is an escape from constant stops and cleaning. transom from algae.
Many owners PVC boat It's a misconception that standard lower unit can handle any condition if you just push the engine up. hydrodynamics It requires a certain diving angle to effectively cool and draw water, and an elongated leg allows you to maintain this angle even at maximum elevation, ensuring stable operation. pump.
There is a misconception that an elongated shaft reduces speed. In practice, with the right screw pitch, the losses are minimal and the gains in the propeller's footprint are minimal. passability You get to go through areas where other engines would have already given up, getting stuck in the mud or hitting hidden driftwoods.
The design of the elongated lower unit implies a shift in the mounting point propeller relatively anticavitationalThis allows the propeller itself to be lowered, while maintaining high clearance for the rest of the outboard motor, and as a result, the gearbox body and the lower unit are higher above the bottom, reducing the likelihood of fatal impacts on hard obstacles.
It is important to understand the difference between a simple “long leg” and specialized solutions for the use of a single leg. shallowStandard long lower units (Long) are designed for high-transe board boats, whereas elongated versions for shallow water (often designated as X-long or specific modifications) change the geometry of the dive. boat-engine work in a mode close to planing, even at depths of 20-30 centimeters.
When you choose, you should look at the material of the lower unit. Aluminum alloys are lighter, but steel is more resistant to impacts against stones. The elongated structure experiences heavy strain on the kink, so metal-strength So if you're planning to actively storm the straits, you'd better pay for a better version.
⚠️ Warning: Installing a long-datewood motor on a low-transcent boat can cause a maladjustment and loss of stability. Always check the manufacturer's recommendations before upgrading.
One of the main reasons for the popularity of these engines is their ability to pass through the water-vegetationTina and algae are often wound up on a lower unit, creating additional resistance and overheating the motor. The elongated leg minimizes contact with the upper layers of vegetation, allowing a lot of water and grass to pass under the screw.
Also, elevated lower unit reduces the risk of damage screw-paddle Logs, boards and other debris, invisible in murky water, often pass under the boat without touching critical nodes, this is especially true in regions with floods or in the deltas of large rivers, where the current carries a lot of water. floating-garbage.
- 🌿 Passage: The ability to overcome overgrown sections of rivers where standard engines stall or overheat.
- 🛡️ Defense: Reducing the risk of damage to the screw and gearbox on bottom obstacles and driftwood.
- ❄️ Cooling: Maintaining effective water intake for the cooling system even with high engine lift.
Technical specifications of elongated lower units vary depending on the manufacturer and power. boat-engineHowever, there are general standards that should be followed when selecting equipment. anticavitational to the water intake hole.
The table below shows a comparison of standard and elongated lower units on the example of popular models with a capacity of about 9.9 hp The difference in length can be from 10 to 20 centimeters, which significantly changes the specifications of the stroke.
| Parameter | Standard lower unit | Elongated lower unit | Difference |
|---|---|---|---|
| The length of lower unit | 435 mm | 565 mm | +130 mm |
| Depth of the screw | Standard. | Enlarged. | Higher clearance. |
| Motor weight | 26.5 kg | 28.0 kg | +1.5 kg |
| Recommended depth | 0.6 m | 0.3 m | shallow water |
⚠️ Attention: Increasing the length of the lower unit changes the moment of inertia. When you turn abruptly at high speeds, the boat's handling can change, requiring addiction.
We should not forget the impact on Shifting the center of gravity of a lower unit can require redistribution of cargo in the boat or displacement of seats, especially critical for small craft, where every kilogram and centimeter affects the differentiation.
Installation boat-engine With extended lower unit, you have to follow certain rules other than the standard version. cross-board If the transom is weak, it can withstand increased strains on the fracture and torsion, and if the transom is weak, it can cause cracks or deformities in the mounting site of the strubcins.
The installation process begins with checking the height of the transom. An elongated lower unit often requires a higher landing to keep the anti-cavitation stove level with the bottom of the boat or just below. Use a template or ruler for precise positioning. bracket engine.
☑️ Preparation for the installation of extended lower unit
After the physical installation, be sure to run a test run on the water. Notice the jet of water coming out of the control hole. If it's weak or intermittent, then the water intake is taking in air, and the motor should be lowered. Also check for no vibrations on the control hole. idle.
It's important to adjust the tilt of the lower unit (trim) correctly, because of the changed geometry, the standard settings may not work, and you may have to experiment with the tilt positions to find the optimal angle of attack to reach the target. gelling.
The long leg engine has its own nuances that directly affect the life of the unit. The main rule is temperature control. Despite the lengthening, the risk of overheating when operating in shallow water remains, especially if the boat speed is low and the engine speed is high.
When moving against the current or in thick grass, watch the temperature indicator (if any) or periodically check the temperature of the body with your hand (caution!). Overheating It can lead to a piston group jamming, which is an expensive breakdown.
Use a temperature control tape on the engine body if there is no regular sensor, which will help to notice the problem with cooling in time.
Check the lower unit regularly for dents and scratches. Even minor damage can disrupt the laminar flow of water, creating cavitation bubbles that reduce the efficiency of the screw. anticorrosion.
Pay attention to the state of affairs as well. sludge Because of the deeper dive and the possible impacts on the sand or silt, the tightness can be broken faster than standard models, and the water entering the gearbox can corrosion the gears.
⚠️ Warning: Never run the engine out of water or with the water intake locked, even for a short time.
The life of seals in elongated lower units may be shorter due to increased vibration and loads. row-shaft Every 100 hours or once a season if the intensity of use is high.
The secret of the durability of the gums
Use a special lubricant for lower unit oils with each replacement. Conventional lithium lubricant can wash out faster, resulting in rapid wear of rubber and water getting inside.
The choice between standard and extended lower unit is often down to operating conditions. If 90% of your outputs are pure water and depths of more than a meter, overpaying for an extended version makes no sense. wilderness And hard-to-reach places are an option.
The cost of these engines is typically 10 to 15 percent higher because of the more complex design and smaller production runs, but this investment pays off with no screws and gearbox repairs after bottom encounters. The only way to ensure that the task is performed in all hydrological conditions..
In conclusion, boat-motor It's a specialized tool that won't make your boat faster in deep water, but it will open doors to places where other routes are closed, weigh your needs, assess the condition of the transom, and go sailing safely knowing that your propeller is protected.
Elongated lower unit is a compromise: you sacrifice the minimum speed for maximum cross-country performance and protection of the engine components.
Frequently Asked Questions (FAQ)
Can you extend the lower unit of a normal motor?
Theoretically, it's possible, but it's highly discouraged without factory components. The breakdown of the geometry of lower unit leads to flux swirls, loss of efficiency, overheating and rapid failure. pumpIt is better to buy a specialized model.
Will the speed of the boat with an elongated lower unit drop much?
With the correct adjustment of the angle of inclination and selection of the screw, the loss of speed will not exceed 3-5 km / h. However, in shallow water you can develop this speed where the standard engine rests in the bottom or loses efficiency.
Is the long-distance lower unit suitable for sea fishing?
Yes, these engines are great in coastal areas with thickets of algae, but you should consider increased weight and wind sailing when transporting long distances in the sea.
How often should you change the oil in the gearbox of such a motor?
The oil change regulations are unchanged, usually between 50-100 hours or once a year, but because of the higher risk of rock leakage, it is recommended that the oil be checked more often for emulsion (water) every 20-30 hours.