Any experienced boat owner knows that the safety of navigation and the ease of operation of a swimming craft are made up of many small things that at first glance seem insignificant. bolt-boltThis small metal ring, mounted on the side or deck, acts as a reliable anchorage point for cables, phalanxes, anchor ropes or mooring ends. Without properly matched and installed rifts, the boat becomes an unmanageable mass that is difficult to moor, anchor or even simply transport on a trailer without risk of damage.
The question of what is a rum on a boat is often asked by beginners who are just beginning to master the water element on PVC or metal vessels. The answer lies in the design itself: it is a force element that takes on enormous loads. In squall winds or strong currents, these are the points on which the weight of the vessel and the forces of nature fall. fastener When it is picked up incorrectly or installed with a faulty technology, the consequences can be dire, from losing an expensive anchor to demolishing a boat from a parking lot, which is why understanding the types of rims and the rules for their operation is a must for every water motor.
In this article, we will discuss in detail how the different types of shell bolts differ, what materials they are made of, and why you can not use conventional household fittings for marine purposes. You will learn how to choose the right place for installation, what tools will be needed for installation and how to avoid the typical mistakes that boat owners make when tuning. boat It is not only comfort, but also a guarantee that your boat will stay with you in any situation.
The main purpose and functionality of the bolts
The main function of the free bolt is to create a reliable point of application of force for rigging. rummy Designed to withstand dynamic loads that occur when rolling, thrusting anchors or mooring tension, the design allows the cable to slide freely or lock in the right position without rubbing against the sharp edges of the hull, which is especially important for PVC inflatable boats where any improperly installed metal element can damage the cylinders.
The scope of the bolts on small boats is extremely wide, and they are used not only to moor to the berth or buoy, but also to attach the transom wheel, install the awning, fix the motor in a transport position or attach the cargo inside the cockpit. On fishing boats, they often tie the kukans to the catch or fix the anchor ropes. fixation: somewhere you need a ring that rotates 360 degrees, and somewhere - a rigidly fixed eye.
Use vertebral dips for anchor ropes to prevent the chain or rope from twisting when the wind or current changes direction.
Special attention should be paid to load distribution. When you attach the rope at an angle, the force to break the bolt increases several times compared to vertical thrust. So when designing the equipment of the boat, you need to take into account the load vectors. If you plan to use the polish for mooring, make sure that it is installed in a reinforced place of the hull, for example, on a hinge bar or a special glued area. Simply screwing PVC into the thin side of the boat without strengthening can lead to the element to be pulled out along with a piece of fabric.
Classification and types of strap anchorages
The marine fittings market offers many modifications of shell bolts, each with its own design features, and understanding the difference between them will help you choose the best option for a particular task. The main division is by type of mobility of the ring and the method of installation.
- 🔩 - A bolt of rumps. It's a classic fixed ring that's rigidly fixed in the housing, ideal for points where the load direction is constant or where maximum rigidity is required.
- 🔄 Rottle nut with a vertebral It's equipped with a movable ring that rotates around a vertical axis, great for anchor locks and places where the cable can change direction.
- 🔽 Foldable (foldable) A ring that can be lowered horizontally, convenient for places where the protruding element may interfere with the movement or storage of the boat.
- 🧱 pym-platform A ring welded or glued to a flat base, often used on aluminum boats to distribute the load evenly over a larger area.
It is worth mentioning separately. duckThe duck has horns to attach the mooring end with an "eight" so that you can quickly fix or give moorings. The rum is a closed ring through which you can put a carbine or tie a knot. The choice between the fry and the duck depends on the use scenario: for permanent binding of the cargo is better than the rummage, for frequent mooring at the pier is a duck.
When choosing, it is also important to pay attention to the presence of additional elements, such as washers and nuts. kit It should include everything necessary for installation, including counternuts to prevent spontaneous unwinding from vibration. PVC boats often use special models with a wide plate-shaped puck, which does not cut the fabric even under strong tension.
Manufacture materials and corrosion protection
The aqueous environment, especially salty seawater, is an aggressive corrosive agent. Therefore, the material from which the shell bolt is made plays a crucial role in the durability of the tooling. Using conventional steel without coating or materials with low corrosion resistance will lead to rapid rusting, loss of strength and, ultimately, to the destruction of the fasteners. Consider the main materials used in shipbuilding:
The most common and accessible option is AISI 304 stainless steel. This material resists corrosion in fresh water and withstands short-term exposure to the marine environment. However, in constant contact with salt water, even AISI 304 can be subject to spot corrosion. For marine expeditions and permanent use in salt water, the de facto standard is steel grade. AISI 316It contains molybdenum, which greatly increases resistance to chlorides.
⚠️ Warning: Never mix different metals in one mounting assembly! Contacting stainless steel with the aluminium hull of the boat in the presence of electrolyte (water) will cause electrochemical corrosion that will quickly break down aluminum. Use insulating pads.
Brass and bronze are another popular material, and they have excellent corrosion resistance and an aesthetic golden color, but they are softer than steel and have less tensile strength. Brass-robs They are suitable for low-load boats or as decorative elements. For power loads, such as anchoring a heavy boat, steel is preferable. There are also zinc alloy galvanic-coated diamonds, but their resource is much lower and they require regular inspection.
Technology of installation of rim bolts on different types of boats
The process of installing the bolt depends on the material of which the boat is made. Installation errors can lead to leaks, depressurization of PVC tubes or destruction of the metal body. Below are the key features of the installation for the main types of swimming equipment.
For PVC-boat The installation requires the use of special glue and reinforcement of the attachment site. You can't just glue the slurry to a thin fabric, the load will tear it off. Usually, the method of sticking the slurry into a pocket of several layers of PVC fabric or installing it on a shaft beam. It is important to carefully degrease the surfaces and withstand the time of polymerization of the glue. Metal boats (aluminium) need to use a sealant and insulating pads.
☑️ Checklist for the bolting-flagging
In the editing on aluminum-boat It is critical to avoid contact with aluminum. Use plastic or rubber sleeves, washers of non-ferrous metals. The hole is drilled exactly for the diameter of the bolt, the edges are cleared of burrs. A layer of marine sealant is applied under the bolt head and under the nut, which will prevent water from entering and oxidizing the thread. After installation, it is recommended to conduct a test load to ensure the reliability of the connection.
The table below compares installation requirements for different materials of the shell:
| Parameter | PVC Boats | Aluminum boats | Plastic Boats (FRP) |
|---|---|---|---|
| Type of fastener | With a wide puck | Bolt + nut + washers | Bolt + nut + sticker |
| Hermetization | PVC Clay | boat sealant | Epoxy resin |
| Isolation. | Not required | Mandatory (plastic/rubber) | Desired. |
| Strengthening | Multilayered fabric | Not required (if the board is thick) | Glass/Epoxy |
Loading standards and safety of operation
Each bolt has a WLL (Working Load Limit) that is not allowed to be exceeded, which is usually indicated by the manufacturer in the product passport or labeling. However, in practice, water motors often neglect this data, relying on the eye gauge. This is a dangerous practice, since the dynamic loads when the anchor is jerked on the wave can be 5-7 times higher than the static weight of the anchor.
To ensure safety, you need to regularly conduct defectiveness Check the rigs for cracks, corrosion, ring deformation or threading, and if you notice that the rim is cruising or that the body material is darkening, immediately dismantle and reinstall it. The weakening of the rig may be caused by vibrations for an outboard motor.
How to calculate the required load?
For mooring, the minimum burst load of the rim must be equal to the displacement of the boat. For anchor rims, the safety margin must be at least 300% of the weight of the anchor system.
Also, remember to use the knots correctly, using the diamond for other purposes, for example, hanging weights on it at an angle other than the calculated one, reduces its effectiveness. The maximum load on the pom is achieved with thrust strictly along the axis of the bolt; with lateral load, the strength is reduced by 40-60%. Always try to distribute the load on several mounting points if you have to work with large weights.
Common mistakes in selection and installation
Analysis of powerboating forums and repair reports reveals a number of common mistakes boat owners make when equipped with crummy bolts. Avoiding these mistakes will save you money and nerves. The first and most common mistake is using construction fittings instead of specialized boat fittings. Conventional anchors or bolts from a construction store do not have the necessary corrosion protection and can crumble in one season.
The second mistake is saving on the number of anchorage points. Trying to use one for all needs (both anchor and mooring and cargo) leads to rapid wear and inconvenience of operation. It is better to install several specialized points: bow pome for anchor, onboard for mooring and aft for towing. The third mistake is ignoring maintenance. The frames need to be periodically lubricated (if this is allowed by the design) or at least washed with fresh water after going to sea.
- ❌ Use of rusty or galvanized (non-stainless) bolts.
- ❌ Lack of sealant during installation, which leads to leaks.
- ❌ The nuts are pulled, leading to deformation of the landing place.
- ❌ Installation of the rims in places where the cable will be rubbed on sharp corners.
A competent approach to equipping a boat with shell bolts is a sign of an experienced boat owner. You should not neglect the quality of the fittings, because on the water it depends not only on the safety of property, but also on the lives of people. Choose proven manufacturers, follow the installation instructions and regularly check the condition of fasteners.
Properly selected and installed, the AISI 316 stainless steel bolt is a safety investment that pays off with no problems at a critical moment.
Frequently Asked Questions (FAQ)
Can you use conventional bolts instead of special bolts?
Not recommended. Conventional bolts are not designed to handle the dynamic tear and bending loads that a bare bolt experiences. A normal bolt hat can break off, and a thread can't withstand a jerk. Only use certified marine fittings.
How often should I change the bolts on the boat?
The life of the product depends on the material and the operating conditions. AISI 316 stainless steel, when properly maintained, lasts for decades. However, once a season, you need to perform a visual inspection and check the puff. If you see signs of corrosion or cracks, immediately replace.
What is the difference between PVC rum boats from rum for metal?
The main difference is the base design: PVC smoke has a wide plate washer or pad for distributing pressure to soft tissue and is often completed with adhesive layer. The metal smear has a standard thread and requires drilling holes, as well as the use of a sealant.
What size of a river to choose for an inflatable boat 3 meters long?
For a boat with a length of 3 meters, the optimal would be a bolt with a diameter of threads M6 or M8 with a ring diameter of 20-30 mm. The larger size can be excessive and weight the structure, the smaller one will not provide the necessary strength.