Operation of the vessel is impossible without a reliable transport system, and the key element here is the use of the boat. bow-restIt is this part that takes on a huge inertial load during braking and sharp maneuvers on the road, ensuring the immobility of the boat relative to the frame, improperly selected or worn support can cause serious damage to both the vessel and the trailer breathed.
Owners of production equipment Moscow plant of specialized cars Often faced with the need to upgrade or replace broken components. Standard solutions may not be suitable for boats with non-standard forehead or too high/low zygomatic lines. In this article, we will discuss in detail the design features of the components, materials of manufacture and algorithms for fine-tuning.
Ignoring the condition of fasteners and rubber shock absorbers can lead to the emergence of backlashes, which, when moving along the highway, transform into dangerous vibrations. keel-stamp It will allow you to do your own diagnostics and avoid costly repairs at the service center, so let's dive into the technicalities.
Design features and types of MHSA stops
The MZSA plant uses time-tested solutions, but the range of trailer models (from 810110 to 810117 and above) dictates different requirements for bow geometry. The main element is the vertical rack, which can be welded or composite, and the support assembly itself. T-bracketwhich is directly connected to the contact area.
The material for the racks is a profile pipe or channel coated with zinc or polymer paint to protect against corrosion. It is important to note that older models may have encountered knots with lower load capacity, which when installing a heavy boat required mandatory modernization. Modern versions are equipped with reinforced elements that can withstand loads of up to 750 kg or more.
Special attention should be paid to the type of attachment of the heel itself to the vertical rack. Some versions use a bolt connection with the ability to adjust the angle of inclination, which is critical for boats with a steep forehead. Other options involve rigid fixation, requiring the exact height of the installation of the entire rack when mounting on the breather.
The compatibility of the stop is determined not only by the width of the breather, but also by the height of the boat in the bow, which requires an individual approach to the choice of model.
Materials of manufacture: rubber, plastic or metal
The contact surface directly in contact with the hull of the vessel is made of various materials, each with its own advantages and disadvantages. high-density rubberIt has excellent shock-absorbing properties and does not scratch the gelcoat, but over time it crumbles and cracks under the influence of ultraviolet radiation.
The alternative is composite materials and hard plastic, which are more durable and resistant to aggressive environments, but can damage the paintwork if they do not have an additional soft layer. Uncoated metal stops are rarely used and only as a base for installing replaceable linings.
⚠️ Attention: Never use metal stops without rubber or plastic linings. Direct contact of metal with the boat hull when vibrating is guaranteed to lead to cracks in the fiberglass or dents in aluminum.
When choosing a replacement, it is important to consider not only the hardness of the material, but also its shape. V-shaped stops They are better at fixing the boat at the course, preventing sideways displacement, while flat platforms (kilblocks) take the main vertical load. Combined variants are considered the most versatile for domestic operating conditions.
The secret of durability of rubber stops
Lubricate rubber parts with silicone lubrication after each trailer wash, which prevents rubber from drying out and microcracking, significantly extending the life of the element.
Diagnosis of wear and the need for replacement
Regular inspection of the bow of the trailer is a mandatory procedure before each long-distance departure. The first sign of problems is the appearance of a backlash at the place where the rack is attached to the frame. If you notice that when rocking the boat with your hand, the emphasis shifts with it, you need to urgently check the tightening of the bolt joints and the condition of the bolt joints. pinch-puck.
Visual inspection of rubber elements can also reveal hidden defects: cracks more than 2-3 mm deep, the crumble of the material or loss of elasticity (rubber became hard as a stone) indicate that the resource of the part is exhausted, the operation of such a stop is dangerous: if it is sharply braking, it can burst, and the boat will slip off the support.
You can measure the condition of the metal base by looking at the traces of corrosion. If the rust has penetrated the paint and you see the swelling, then the process of breaking the metal is from the inside. In the welds, microcracks often form, which, when you are under dynamic load, quickly grow, threatening the integrity of the entire structure.
☑️ Diagnostics of the nasal node
Instructions for replacing the nose stop yourself
The replacement process does not require complex equipment, but requires accuracy and consistency of operations. First, you need to provide access to the site, you may need to remove the winch or cable if they interfere with the dismantling. Put wooden bars under the nose of the boat to fix its position and relieve the load from the replacement element.
Using the appropriate sized wrenches, unscrew the fasteners that hold the old stop or the entire rack. Often the bolts cling to dirt and moisture, so it is recommended to pre-treat the joints with penetrating lubricant (WD-40 or analog). After dismantling the old parts, carefully clean the seat on the breather from rust and dirt.
The necessary tool:Set of carob keys (13, 17, 19 mm)
2. Penetrating lubricant
3. Metal brush
Dynamometer key (preferably)
Carving fixture (medium strength)
Install a new one. stop-pieceIf the old ones have thread scuffs, use the thread locker when you build them, because the vibration when you move can weaken even tight nuts. After installation, make the final puff and check the reliability of the fixation.
When installing a new stop, lubricate the bolt thread with graphite lubricant or copper antifriction composition - this will make it easy to unscrew them in the future, even after winter operation.
Accurate adjustment of height and inclination angle
The right set of height is the key to safe transportation. The boat must rely on the nose and rear rollers (or keel blocks) simultaneously, forming a single line of support. If the nose stop is set too high, the boat will hang on the nose, creating excessive pressure on the breather and rear overhang. If too low, the load will be redistributed to the rear of the trailer, which can lead to unloading the car's coupling device.
Many MHSA models have vertical ridge holes or cross-sectional slacks to adjust the height, loosen the fastener, set the height to keep the boat flat, and tighten the bolts. The T-slack angle is also adjustable, repeating the angle of the boat's forehead for maximum contact area.
| Parameter | Norma. | Permissible deviation | Consequences of violation |
|---|---|---|---|
| Height of thrust | In the same plane with the back rollers | ± 10 mm | Body skewing, cracks |
| Gap in connections | Missing. | 0 mm | Vibration, welding breakdown |
| Area of contact | As much as possible | - | Local damage to the shell |
| Bolt tightening | On the dynamometer. | ± 5 Nm | Self-twisting when vibrating |
After adjustment, be sure to take a short-distance test ride and re-check the tightening of all elements. The thermal expansion of the metal and the initial laying of parts may require correction of the tightening force.
Tuning and strengthening of the structure for heavy boats
Heavy boat owners often find that the standard MZSA stop is not enough, and in such cases, reinforced racks from a powerful channel or a profile pipe with a large cross-section are used. A popular solution is the integration of the nose stop with a winch rack, which allows you to create a single rigid structure that distributes the load.
Also worth considering is the installation of height adjustable supports with a screw mechanism, which allows you to quickly adapt the trailer to different boats without the use of tools and wrenches, screw mechanisms must be made of stainless steel or have a reliable anti-corrosion coating.
⚠️ Attention: When self-reinforcing the structure, do not weld new elements to the main power units of the frame without calculating the loads. Overheating the metal during welding can reduce its strength specifications and lead to the destruction of the frame.
In addition, side restraints (bumpers) can be installed on the bow, which will prevent the boat from moving left-right when cornering, especially for narrow boats with high sailing or when driving on broken roads.
adjustable lifehack
Use a laser level set on a flat area to set the boat’s support line perfectly horizontal before fixing the stops.
How often should you change the rubber linings on the stop?
Resource rubber depends on the operating conditions and storage. On average, for year-round use and storage in the open air, it is recommended to replace every 3-4 years. If you notice deep cracks or crumble material - change immediately, regardless of the service life.
Can I use the focus of the trailer from another manufacturer on MZSA?
Yes, it is possible, but it will require redesign of the seat, and the mounting standards of different manufacturers (MZSA, SKIF, VSW) may differ in the distance between the holes and the diameter of the bolts, you will need to make a transition plate or digest the bracket.
How to lubricate the metal part of the stop, in contact with the boat?
There is no need to lubricate the contact, it must be dry or through a rubber gasket. Lubrication of the metal will lead to the accumulation of dirt and sand, which will work as an abrasive, scratching the boat hull. It is allowed to use Teflon sprays to protect against corrosion of the metal base itself, but not the working surface.
Why does the boat shift sideways when transporting, although the emphasis is intact?
Sideway displacement most often indicates improper alignment of the boat on the trailer or wear of the side rollers / kilblocks. Also, the cause can be too smooth surface of the stop or, conversely, the lack of lateral support. Check the pressure in the tires of the trailer - different pressures also cause rolling and shifting of the load.