Self-manufacture of a vehicle for the transportation of a boat is not only a budget saving, but also an opportunity to get a perfectly fit for your needs. boat-trailerMany inflatable boat owners face the problem when production models are too wide or do not take into account the specifics of storing inflated water. PVC That's why the question of precise dimensions is becoming a priority.
Before taking up the welding machine, you need to clearly understand that drawing In this case, it's not just a drawing, it's a technical necessity. A mistake in calculating the width or the length can cause the boat to deform during transportation or, worse, to fly off the frame at high speed. constructionA one that will last for years.
You will have to consider many factors: the type of profile fixation-wise transom-wheelThe right geometry will ensure stability on the track and minimize the load on the chassis of the car. Let's go into detail at each stage of the design.
Basic parameters and dimensions standards
The initial size is the foundation of the entire project. Dimensions The future trailer is directly dependent on the model of your inflatable boat, but you should always have a margin of safety and space. Standard width of the roadway dictates its conditions, but for passenger trailers there are more flexible frameworks that allow you to vary. parameters depending on the task.
The length of the platform is calculated based on the total length of the boat in an inflated state, but with the obligatory consideration of overhangs. Transport length It should not be close to the size of the boat, as when moving on irregularities, dynamic displacements are possible. Experienced craftsmen recommend adding at least 20-30 cm of reserve to the length of the boat in front and rear.
Width is an even more critical parameter, especially for PVC boats So, the cylinders have the ability to change the volume slightly depending on the temperature, so distance The frame should be so that the boat lies loose, but does not dangle from side to side, a narrow frame can damage cylinders, and too wide will create problems with dimensions on the road.
⚠️ Note: When calculating the width, take into account not only the cylinders, but also the possible placement jock-duck or additional equipment inside the cockpit, which can act beyond the dimensions of the bottom.
The height of the board also plays a role, especially if you plan to carry a boat in a half-deflated state or with a set boat. motorLow sides are convenient for loading, but may not provide proper fixation. High sides increase the sailing and overall weight of the structure, which negatively affects the fuel consumption of the tractor.
Calculation of the length and width of the frame for a specific model
For accurate calculation drawing You need to measure your boat in a fully inflated state, put it on a flat surface, and measure the maximum length from nose to transect. Add 15-20 cm to the value for the stock. That's the inner length of your boat. If you plan to install a keel shield or a winch on your nose, add another 10 cm.
The width is calculated from the widest position of cylinders. It is important not to overdo it: the standard width of a passenger trailer without special permission should not exceed 255 cm (including wheels and wings). Inner width The frame should be 5-10 cm wider than the maximum width of the boat, which will ensure a safe clearance and allow you to easily lay the boat even in windy weather.
In the creation The cross-sections should be positioned to support the soft bottom of the boat, preventing it from sagging between the cylinders. The cross-sectional distance is usually 40-60 cm. NDMA (low pressure inflatable floor) requirements are less stringent, as the bottom itself holds the shape, but support is still needed.
Use paint tape to mark the contours of the future frame in life size on the floor of the garage - this will help to visually assess the proportions before welding.
Do not forget about the height of the frame installation relative to the axis. Clearance. It should be sufficient to ensure that when loading the boat it does not scratch the bottom on the ground or curbs. The optimal height of the board from the ground in running order is 35-45 cm. This facilitates loading and unloading without using a high slipway.
Selection of materials and profile pipe
The durability of your design depends on the chosen one. metalFor boat trailers that are in constant contact with water (and often salt), the best choice is a profile pipe made of zinc-coated steel or ideally stainless steel. Stainless steel, most craftsmen choose a conventional steel pipe followed by hot galvanizing or high-quality painting.
Optimal section of the profile pipe for the frame of a passenger trailer under PVC boat 40x20 mm or 50x25 mm with a wall thickness of 2 mm. A smaller cross section (for example, 20x20) may not support the weight of a motorized boat and equipment, especially when driving on bad roads. A thicker profile will increase the weight without significant gain in strength.
For cross-sections, which will rest the bottom, you can use a tube of smaller cross-section, for example, 20x20 mm or even 25x25 mm. the main thing is to ensure their reliable attachment to the spars. Welded seams should be solid, without burns and indigestion, since they are the ones who experience the main loads on twisting.
| Type of element | Recommended tube cross section (mm) | Wall thickness (mm) | Note |
|---|---|---|---|
| Longerons (basic) | 50 x 25 or 40 x 20 | 2.0 | supporting part of the frame |
| Cross-sections | 25 x 25 or 20 x 20 | 1.5 - 2.0 | Boat support |
| Board (optional) | 20 x 20 or 25 x 15 | 1.5 | To fix the cargo |
| Breathing | 60 x 40 or 50 x 50 | 2.0 - 3.0 | Clutch anchorage area |
When purchasing materials, pay attention to quality corrosion-proofingIf you're taking a black pipe, you should immediately budget for sandblasting and galvanizing. Paint, even the most expensive, on welds doesn't hold well and will quickly start climbing from vibration and contact with water.
Design features of the drawing: breathed and the side
The breather is the element that connects the frame to the coupling device of the car, and its length determines the stability of the trailer on the track. The rule of thumb for boat trailers is that the longer the breather, the more stable the trailer is, especially when braking. The optimal length of the breather is 1.5 - 2 meters from the front crossbar of the frame to the coupling head.
There are two main types of breather design: straight and V-shaped (triangular). V-shaped breather is harder to twist and better distributes loads, but more difficult to manufacture and takes up more storage space. Direct breather is easier to implement and is often applied to the construction of the wind. drawings light-trailer PVC boats.
The side frame can be made in the form of a solid box or an open structure with corners. flyboat They often make folding sides or do without them, using only soft paddles or crossbars, which reduces weight and makes it easier to access the boat, but if you plan to carry cargo in crates, removable boards will be very useful.
Do you need a broken breath?
A broken breather (with a bend) is often used to lower the center of gravity or bypass wheel arches. For a light PVC trailer, this is rarely necessary, since the boat already has a low profile. A straight or V-shaped breather will provide better handling.
It is important to provide anchorage points winches Or a persistent roller on the nose, which needs to be reinforced with additional scarves, and the load on the cable during loading can be significant, especially if the boat is heavy and loading occurs on the rise.
Chassis assembly and axle installation
Proper installation oxide The axle is not placed strictly in the middle of the frame. For single-axle trailers, the rule is that the center of the axle should be 40-45% of the platform length from the rear side (or, respectively, 55-60% of the front cut), This is necessary to create the correct pressure on the coupling ball of the car (usually 25-50 kg).
If you move the axle too far back, the beak of the trailer will pull upwards, creating a dangerous unloading of the rear axle of the car. If too far forward, you will put excessive load on the farcrep, which can lead to its failure. Make sure to carry out a preliminary fitting with the cargo.
- 🔧 Ressors or torsion: For light trailers under PVC boats often use torsion axles (without springs), they are more compact and do not require maintenance, but springs are cheaper and easier to repair.
- 💡 Hubs: Choose hubs with bearings of the right size (often 185/13 or 175/13) and pay attention to the number of studs (usually 4 or 5).
- 🛡️ Wings: The wheel should be closed at least 90 degrees and have sprayers so that water and dirt do not fly on the boat and the body of the car.
The axis is attached to the frame through stepladders or welded platforms. spring It is important to properly install the bumpers and shock absorbers (if they are provided by the design) to extinguish the vibrations. For a trailer under a light boat, shock absorbers may not be necessary if long-distance springs are used.
⚠️ Attention: Before final welding of the axle mounts, be sure to test rolling with a load simulating the weight of the boat to check the balancing and lack of "wagging."
☑️ Check of the running gear
Finishing and corrosion protection
After completion of welding and assembly constructionThe most important step is rust protection, and the water, salt, sand and reagents on the roads are the main enemies of metal. drawing saved