The operation of water technology inevitably involves the risk of collision of the underwater part of the engine with solid objects. Sand, stones, snags and even concrete moorings can cause serious damage. propeller and body gearboxThat is why boat owners are looking for reliable ways to minimize the effects of such incidents by considering buying specialized accessories.
The market offers many solutions, from simple treads to complex protection systems, depending on the type of boat, the conditions of navigation and the owner's budget, and well-chosen protection can save significant money on repairing or completely replacing expensive knots.
In this article, we will take a closer look at what types of protection exist, how they differ and what to look for when buying. You will learn about materials, installation methods and nuances that are often overlooked by beginners.
Why you need protection of the screw and gearbox: risk analysis
The main function of the protective casing is to take the blow, and when faced with an obstacle, it is the person who suffers, not the screw or body. gearboxThis is especially true for those who often swim in shallow waters or in unfamiliar waters.
Without additional protection, even a small stone can bend the screw blades, which will lead to vibration, loss of traction and premature wear. bearingMoreover, the deformation of the screw often transfers the impact load on the lower unit shaft, which is fraught with expensive repairs.
⚠️ Warning: Lack of protection on the new engine may cause a denial of warranty service if it is proved that the failure was caused by an impact on the obstacle.
In addition, treads often play a role. anticavitationalIt's a way of improving fluid dynamics and reducing noise when you're driving, which makes swimming more comfortable and making the engine more efficient.
Types of protection: from simple protectors to complex systems
The modern water accessories market offers several basic types of protection, depending on whether you want to protect it: just the screw or the entire bottom unit.
The most popular propeller-treadThese are rings or casings that are mounted directly on the propeller, and they protect the blades from impacts from the side and partly from the top.
- 🛡️ Ring protectors - cover the screw in a circle, protecting from side impacts.
- 🛡️ Full casings - close the screw from all sides, often used on electric motors.
- 🛡️ Protecting the gearbox - special linings on the "leg" of the engine, taking the blow on themselves.
It is worth mentioning separately. lower unitThese are metal or composite pads that are attached to the shaft between the screw and the gearbox body, which prevent the grass from winding and fishing lines from being blown.
The myth of total protection
Many people think that protecting the propeller makes the motor completely invulnerable. It's not. A strong impact on concrete or rock can damage even the strongest tread, transferring the impact energy to a lower unit shaft or veneer, and only reduces the likelihood of critical damage.
Manufacturing materials: steel, aluminum or plastic
The durability and effectiveness of protection are directly dependent on the material, each with its own advantages and disadvantages that must be considered.
Stainless steel These treads can withstand severe shocks, but they're heavier and more expensive, and aluminum alloys are lighter, but they can deform when they're hit hard.
| Materials | Strength | Weight. | Price. |
|---|---|---|---|
| Stainless steel | High. | Heavy. | High. |
| aluminum | Medium | Light. | Medium |
| Plastic/Composite | Low. | Very light. | Low. |
Plastic and composite options are often used on electric motors or low-power gasoline engines, and they are cheap and light, but can split when hit hard.
For powerful engines and difficult conditions, choose only stainless steel. For quiet fishing in shallow water, high-quality aluminum will also work.
How to choose protection for your type of motor
There are no universal solutions. When choosing protection, you need to consider engine power, boat type and driving style.
For mounted-engine Weight is critical in PVC boats, and too heavy a tread can disrupt the balance of the transom, in which case lightweight aluminum or reinforced plastic models are optimal.
If you own a boat with a stationary motor or a powerful "pendant", the priority is maximum strength. steel-hull with extra ribs of stiffness.
⚠️ Warning: When buying, be sure to check the compatibility of the tread model with the diameter of your screw and the pitch of the shaft thread. Incorrect selection can lead to beats and vibrations.
It is also important to consider the type of fuel. For two-stroke engines, good streamlining is important so that the exhaust does not disrupt the operation if it is carried out through the screw hub.
Before buying, measure the diameter of the screw hub and the distance from the transom to the screw, which are often required for the correct selection of a protection model.
Installation and maintenance: step-by-step instructions
Installation of the propeller and gearbox protection is a process that requires precision and adherence to technology, and errors in installation can lead to the loss of the screw or damage to the shaft.
Before work begins, access to the propeller must be provided, the boat should be lifted ashore or use a special lift, the engine should be silenced and cooled.
☑️ Preparation for the installation of protection
The first thing you do is remove the screw itself, and you unscrew the nut (usually counterclockwise), remove the locking washer and the veneer, and you have to clean the shaft thoroughly from old lubrication, algae and corrosion.
Then you put a tread on the shaft, and it's important to make sure it sits tightly and without any skewing, and if the design involves mounting through the screw hub, make sure that the length of the thread is sufficient for a reliable fixation.
Assembly sequence:1. Glubricate the shaft with water-resistant lubrication.
2. wear protection (if it is composite).
3. Set the screw and the veneer.
4. Tighten the nut with a dynamometer key.
5. Untighten the tendrils of the locking washer.
After installation, it is recommended to conduct a trial run in shallow water to ensure that there is no vibration and extraneous noise.
Economic feasibility of purchasing protection
Many owners are wondering whether to spend money on an accessory that can cost as much as 10-20% of the cost of a new screw?
Replacing a bent screw isn't just about buying a new part; it's also about the time spent commuting to the service, dismantling and installation, and if the gearbox hits you, you can go into hundreds of dollars.
Statistics of service centers show that the presence of a tread reduces the likelihood of critical damage to the gearbox when hitting a stone by 70%.
So buying protection is an investment in the safety of expensive equipment, and even if you have to change the tread after a big impact, it's cheaper than repairing a lower unit shaft or replacing the gums.
Do I need to remove protection for the winter?
Remove the protection of the screw for winter storage is not necessary if it is installed correctly and does not have hidden cavities where water can freeze. However, if you keep the motor assembled, it is recommended to remove the screw and tread, lubricate the shaft with conservation lubrication and store the parts in a dry place, this will prevent boiling and corrosion.
Does the protection affect the speed of the boat?
A well-designed tread has minimal impact on hydrodynamics, a speed loss of less than 1-2%, which is almost imperceptible to the eye, and cheap or improperly installed models can create additional drag and cavitation.
Can I paint the screw protection?
Yes, most metal treads can be painted with anti-fouling paint, which not only improves the appearance, but also protects the metal from corrosion, and prevents algae from fouling in standing water.
Electrical protection: are there any differences?
For electric motors, protection is often part of the design (sheathing). If you buy a separate tread, make sure that it does not block the flow of water to cool the engine if the cooling is water. Electric motors are critical weight, so aluminum options are preferable to steel.