The seaworthiness and comfort of sailing on a small vessel directly depend on the quality of its equipment. rummyThis seemingly simple piece of hardware takes on enormous loads when towing, anchoring or docking to shore. Mischoice or careless installation of this piece can lead to the loss of the boat or even injuries to the crew.
Owners of both PVC inflatable vessels and metal "kazak" often underestimate the importance of properly installing rim bolts. In this article, we will discuss in detail what types of fasteners exist, what is different from the other types of fasteners. stainless steel It's about silumin and how to secure the tow point yourself, and it's about avoiding water emergencies with a good approach.
The modern market offers many options for making this part, from cheap plastic rings to massive forged goods, and every boat owner needs to understand the difference between them. We will look at the technical nuances that are often overlooked when buying equipment in stores.
Types of rame bolts and materials of manufacture
The first thing that customers face is a variety of materials, dominated by silimine, stainless steel and plastic. Silumin It's a low-cost, but it's very fragile, and when you're under a lot of stress, like a ripple, a silimine fracking ruffle can just burst, leaving you without anchor or berth.
The gold standard is considered stainless steel This material has excellent corrosion resistance in salt water and high tensile strength, it withstands multiple load cycles and does not break down under the influence of ultraviolet light. For serious water walks, this is the only right choice, despite the higher cost.
Plastic rim bolts are often installed by manufacturers on budget models of PVC boats. They do not rust or scratch the side, but their bearing capacity is limited. Use them to anchor on the current or tow another vessel is strongly discouraged. They are only suitable for easy mooring in calm weather.
- 🔩 Silumin: Cheap, lightweight, but fragile and prone to corrosion in the long run.
- 🛡️ Stainless steel: maximum strength, durability, resistance to salt water.
- 🧸 Plastic: It is not a lightweight, it is suitable only for minimal loads.
⚠️ Warning: Never use silimine bolts to anchor the end on fast current or at sea. If you break the anchor, you risk losing not only the cargo, but also damage the side of the boat with departed fragments.
Features of fastening on PVC boats
Installing a rump bolt on an inflatable boat requires a special approach, because it is about the tightness of the cylinders. The standard procedure involves gluing a special area (pig) to the cylinder. This uses a two-part polyurethane glue compatible with the material of the boat (PVC or Hypalon).
There are two main types of PVC fasteners: through and overhead. Through-cutting This involves passing the bolt stud through the cylinder using special sealing gaskets, which is the most reliable way, since the load is distributed over a large area and transmitted directly to the internal structure of the cylinder or transom plate.
The overhead dice are only attached to the outer nickel, and the advantage is that you don't have to break the integrity of the balloon with a drill, but if you push hard, you run the risk of tearing the site off with a piece of fabric if the glue is applied with a violation of technology. boat-modelSome manufacturers prohibit end-to-end installation in certain areas.
☑️ Preparation for PVC-fired diamond installation
When choosing a place to install, it is important to consider the angles of departure of the cables. The rum should not rub against the side at a sharp angle, otherwise it will rub the fabric in one season. The ideal position is when the cable comes out of the water and goes to the tangent mount, without sharp inflections.
Installation on metal and wooden boats
In the case of aluminum or steel boats, the task is simplified in terms of the strength of the base, but complicated by the fight against corrosion. You need to drill the board carefully, removing the shavings so that it does not damage the paint or get into the machinery. epoxy or a special sealant in the hole before tightening the nut.
For wooden vessels, such as classic lifeboats or modern plywood structures, it is critical to prevent rotting around the fastener. The bolt must be made of stainless steel or brass. The contact of dissimilar metals (such as steel bolt and aluminum hull) in seawater causes electrochemical corrosion that rapidly destroys the hull.
When mounting on thin metal (less than 2 mm), you need to use reinforcing washers or pads on the inside of the side, this will prevent the metal from deforming under load and pulling the fastener. If the boat has a complex geometry of the board, sometimes it makes sense to weld the base of the dimp, pre-cleaning the metal to shine.
| Type of body | Recommended fastener | The need for a sealant | Risk of corrosion |
|---|---|---|---|
| PVC (Inflatable) | Through bolt + pentacle | High (glue) | Low. |
| aluminum | Bolt + puck + nut | Medium (silicone) | Tall (galvanic) |
| Steel | Welded or bolted | Tall (paint/sealer) | Medium (rust) |
| Tree/Fanera | Broad-pucked bolt | High (varnish/tar) | Medium (rotting) |
⚠️ Note: When drilling aluminum side, use only metal sharpened drills for non-ferrous alloys to avoid burrs that can cut your hands or damage the cables.
What is a galvanic pair?
These are two different metals bonded together in an electrolyte (seawater), one metal (more active, like aluminum) begins to break down, protecting the other (less active, like steel), and to avoid this, use insulating pads or lubricate the thread with graphite lubrication.
Rym-bolt, rim-nut or rim-pin: which to choose?
The structural performance of the fastener plays no less a role than the material. Rom-bolt. It's a classic solution where the ring and the threaded rod are integrated, and it's robust, but it requires a through hole and access to the inside of the side to twist the nut.
Rump nut It's a ring with an internal thread, and it's wound up on a normal hairpin or a bolt that's already in the body, and it's convenient if you just need to replace the ring without changing the entire structure, or if the length of the flight requires you to tailor the hairpin individually, but there's a weak spot in the connection, because the threaded connection can unwind with vibration.
There are also rotary dice that allow the cable to change direction without twisting, which reduces wear on the cable itself and reduces the load on the anchor point when the wind or current changes. For anchor systems, the rotary mechanism is a great solution to prolong the life of the equipment.
When choosing, consider the radius of the ring's bend. A ring that is too thin can cut a synthetic flange under tension, and a ring that is too thick can take up a lot of useful space on a carbine or a vertebral. The optimal thickness of the ring bar should correspond to the diameter of the cables you use.
Load calculation and safety
Many boat owners mistakenly believe that any dimple is enough for a small boat, but the force of inertia when abruptly stopped or jerked on a wave can be many times higher than the static weight of the vessel. If a boat weighing 200 kg moves at a speed of 10 km / h and abruptly stops at the anchor shaft, the load on the anchor point can briefly reach several hundred kilograms.
For inflatable boats up to 3 meters long, squirrels with a tear load of about 300-500 kg are usually enough. For larger vessels, especially those operating in open water, this figure should be at least 1000 kg. Always look at the manufacturer's markings. If there is one, it is better to be safe and choose a more powerful product.
Check the bolt thread regularly. Salt deposits can coke the thread, and in an emergency, you can't quickly unscrew the nut or replace the cable. Lubricate the thread with silicone or graphite lubricant once a season.
Remember the aging factor of materials. Even stainless steel can become microcracked over time due to metal fatigue, especially if the rum is constantly experiencing vibrational loads from the engine. Visual inspection before each season is a mandatory procedure.
Maintenance and replacement of elements
Care for the bolts is simple but necessary. After each trip in salt water, it is advisable to rinse the mounts with fresh water to wash off the salt. Periodically check the nut tightening - vibration on the water weakens the connections very quickly. Use growers (spring washers) or a thread locker during installation.
If you notice that the pencil on the PVC boat has started to recede or water has leaked under it, you should immediately remove the crowbar, dry the gluing site and re-glue it. Operating a boat with broken seals in the mounting area is unacceptable. For metal boats, the sign of a problem is the bloating of paint around the bolt or the appearance of red streams.
Replace the worn-out rift with a similar or more powerful one. Don't reduce the diameter of the mount. If the old rift was on the M8, don't put the M6, even if it seems that the loads are small. Safety on the water does not tolerate compromise.
⚠️ Warning: Do not use conventional construction silicone or bath sealant to fix the bolts; they do not hold the tear load and are destroyed by the influence of gasoline and oil; only specialized marine sealants or polyurethane adhesives.
A properly installed stainless steel ruffle bolt is a guarantee that your boat will stay with you even in stormy weather.
FAQ: Frequently asked questions
Can I stick a PVC crumb to a boat without drilling?
Yes, there are overhead dips on a powerful adhesive basis, but their reliability is lower than that of through, they are only suitable for light cables and calm water. For anchor or towing, you must necessarily have a through mount through a penet.
What is the best bolt diameter for a 3.5 meter long boat?
For boats of this size (for an outboard motor 5-10 hp) the standard is threading. M8 or M10The smaller diameter (M6) may not withstand the jerk at anchoring, and the larger diameter (M12) is already redundant and requires serious strengthening of the transom.
How to lubricate the bolt so that it does not rust?
The best thing to do is to use a silicone spray lubricant or a graphite lubricant, and the normal machine oil will wash away quickly with water, and the lithium lubricants can wash out and collect sand, and it's important to lubricate both the threads and the moving parts of the ring.
Why did the silhouine rupture?
Silumin is a very hard alloy, but it's brittle. It doesn't tolerate shock and bending. If the fry burst, it's a dynamic overload that the material couldn't withstand. Replace it with a stainless steel product.
Do I have to put the washers under the screw-bolt?
A wide washer (or two) increases the area of the pin and prevents the material from being pushed through the boat or the metal from being deformed.