The desire to turn an ordinary inflatable boat into a full-fledged sailing boat visits many owners PVC structuresAnd using wind instead of a gasoline engine not only saves a lot of fuel, but also glides silently across the water, scaring fewer fish. rubber-boat It was not originally designed as a sailboat, and its rollover resistance is much lower than that of rigid hulls.
Making sailing weapons yourself is a complex engineering process that requires accurate calculations and high-quality selection of materials. In this article, we will discuss all the stages in detail: from choosing the type of sailing to the final configuration. rankout It's important to understand that homemade craft must not only be functional, but also safe, because errors in the calculations can lead to loss of the craft or injuries.
Before you start opening the fabric and assembling the mast, you need to decide on the type of sail that will be most effective for your model of boat. loading capacity And the cylinder widths are different for all models, and we're going to look at proven options that are easy to implement in garage conditions using the tools and materials available.
Selection of type of sailing weapons for inflatable boat
The first and most important step is to choose a sailing scheme, because it depends on the stability of the vessel and the complexity of the entire construction. squirt-sail Or gaffe, because they allow you to use the wind efficiently, even at a sharp angle. The straight sails that are typical of large boats on a small boat will work poorly because of their inability to go against the wind.
Special attention should be paid to the sailing center (CPC), which should perfectly coincide with the center of lateral resistance (CBS) of the hull. If the CPU is shifted too far forward, the boat will constantly turn its nose against the wind, which is a phenomenon called the "CBR" phenomenon. slouchinessIn the reverse situation, when the sailing is too large in the aft, the boat will be nose-to-mouth in the wind, and it will be almost impossible to hold the course without constantly shifting the steering wheel.
For beginners, the best choice is a simple triangular shape or sprint scheme, where the sail is stretched between the mast and the hafel, which is easy to remove and put, and also requires a minimum amount of money. riggingComplex shapes with a sickle-shaped front scallop are best left for experienced shipbuilders, as they require professional cut and reinforcement of the edges.
- 🌬️ Slanted sail: It is the most versatile, allows you to walk beidewind and has a simple control design.
- ⛵ Sprint sail: Convenient because it does not require galsa, but requires the presence of a hafel and additional fastening.
- 🔺 Bermuda sail: It is highly efficient, but difficult to tailor due to the need for an accurate cut according to patterns.
For an inflatable boat with a soft bottom and low sides, excessive sailing becomes a management problem and a safety threat. The optimal area for a single or two-seater boat is usually 3 to 5 square meters, which allows you to navigate comfortably in winds of up to 5-6 meters per second.
Selection of materials and calculation of the sail area
Choosing a fabric for a sail is a question that directly depends on the durability of your design and its performance. Unlike professional yachts, which use expensive dakron or laminated fabric, for a homemade option is quite suitable. quilt (AB-1), a dense lausan, or even a used parachute cloth, the main requirement for the material is minimal extensibility and high resistance to ultraviolet radiation.
The sail area is calculated from the displacement of the boat and the desired speed. There is a rule of thumb that for every square meter of the sail area, a certain number of kilograms of the weight of the boat with the crew must be accounted for. If this is not the case, the boat will either not budge in low winds or burrow its nose in a wave when reinforced. airflow.
When buying material, be sure to pay attention to its density, which is measured in grams per square meter. For small boats, the optimal indicator will be a density in the range of 150-200 g / m2. oxford or tarpaulin, it is not recommended to use, since they have a large weight and high sailing, which creates an extra load on the mast and can lead to rolling.
⚠️ Warning: Never use plastic film or thin covering materials for the garden as a sailboat. Under the influence of solar heat and wind load, such material will quickly lose strength and burst at the most inopportune moment, leaving you without moving.
To strengthen the seams and edges of the sail, you need to purchase a strong synthetic thread, such as lausan or capron, with a thickness of at least 0.5 mm. Conventional cotton threads will quickly rot from moisture and sunlight, which will lead to the destruction of the entire structure. pockets under the mast and gaffer, as well as to strengthen the angles of the sail.
How to calculate the area of a triangular sail?
The area of the triangular sail is calculated by the formula: S = 0.5 A B, where A is the height of the mast (liquor), and B is the length of the lower skatorina (geek), for a more accurate calculation of complex shapes, the area is divided into several triangles and summed up their values.
Instructions for sewing sails DIY
The process of tailoring a sail begins with the creation of a precise life-size pattern that can be done on the floor of the garage or on the pavement using chalk and a long ruler. The pattern must take into account not only geometric dimensions, but also technological allowances for flexing edges and making pockets for the construction of the cartridge. rankoutAn error in the construction of the pattern even a few centimeters can lead to a swaying of the sail and loss of its aerodynamic properties.
Cloth opening should be done with extreme caution, observing the direction of the threads of the base and duck, as the ability of the sail to keep shape depends on this. The seams should be done in double stitches with increments of no more than 5-7 mm, using a strong synthetic thread. To prevent the cloth edges from falling, it is recommended to melt the sections with a soldering iron or a hot knife, if the material is a solid synthetic thread. synthetic.
The focus is on the corners of the sail, which carry the main wind load, where the fabric is folded in several layers and cross-stitched, forming a solid platform for mounting luvers or crocheting, and rings or braces are sewn into the lower corners of the sail. phala and the boats through which the sail will be controlled.
☑️ Checklist for tailoring sails
After stitching the main cloths, you need to fit on the assembled mast to check the size of the pockets. Mast and hafel pockets should be free so that the rangout can easily enter and exit them, but dense enough that the sail does not hang around. If the pockets are too narrow, the fabric will quickly be rubbed, and if too wide, the sail will deform under the wind.
Rangout production: mast, geek and gaffle
Rangout is a load-bearing element of sailing weapons, so the choice of material for its manufacture must be approached with the strength and weight. For homemade structures on inflatable boats, wooden bars of spruce, pine or larch are most often used, since they are good elasticity and easy to handle. Aluminum pipes are also suitable, but they are heavier and require special skills for the construction of the aircraft. drilling and connections.
The mast should be placed in a special glass or nest, fixed on the transom bank of the boat. The mast should be hinged so that in the case of a strong gust of wind it can fall into the water without overturning the boat. Hard fixation of the mast in a vertical position is unacceptable, because this creates a huge huge gust of wind. sailing and the risk of capturing the vessel in a squall.
Geek and gaffer are made of the same materials as the mast, but have a smaller cross section. At the ends of these elements, blocks or vertebrae are installed to conduct the skunks and phalls. Wooden rangout must be treated with olive oil, varnish or oil to protect against moisture and rot, especially if you plan to use a boat in salt water.
| Rangout element | Recommended material | Diameter/Section (mm) | Weight (kg/m) |
|---|---|---|---|
| Mast | Ew, Pine. | 40-50 | 0.8 - 1.2 |
| geek | Larch, Aluminum | 30-40 | 0.5 - 0.9 |
| gaffe | Pine, spruce | 30-35 | 0.4 - 0.8 |
| A glass of mast | Steel, PVC pipe | 60-70 | Depends on the material. |
To connect the parts of the rankout and rigging, metal shackles are used that can be made independently of sheet aluminum or stainless steel. All sharp corners of metal parts must be carefully ground so as not to damage the fabric of the sail and the sea. balloon The safety of all components is checked under load before they are released into the water.
Fixing and rigging system
Mounting the mast to the body of an inflatable boat is the most critical node of the entire structure, requiring maximum reliability and thoughtfulness. Simply tying the mast with ropes to the ducks on cylinders is inefficient and dangerous, because it creates stress points that can wipe out the rods. PVCThe optimal solution is to use a removable transom glass or a special mast step-platform.
The scots and the stoats are made from a wicker synthetic cable with a diameter of 4-6 mm, which does not absorb water or stretch under load, and the scots are controlled using blocks fixed on the boat or at the very rankout, which reduces the force required to control the sail. rigging They should be equipped with stoppers or clots so that they do not spontaneously poison themselves.
An important element of the system is the achterstag or waterstags, which keep the mast from falling backwards or to the sides. Inflatable boats often use a scheme without rigid tags, where the mast is held only by the efforts of the sail and the crew, but for the safety of the beginners it is better to provide at least one safety safety plan. fella.
⚠️ Attention: When installing the mast, make sure that the lower end of the mast (heel) does not rest directly on the inflatable floor of the boat. Be sure to use a rigid lining or a wooden bar distributed across the cylinders to avoid damage to the bottom by the sharp edge of the mast.
For quick assembly and disassembly, all connections are better done on quick-removal carabiners or squeakers, which will allow you to remove the sail in minutes when the weather worsens or before passing under a bridge. sailboat.
Sailing adjustment and safety
The first self-made sailing should be in calm weather and shallow water, where you can quickly sink in case of danger. The initial setup is to balance the boat: moving the crew or cargo back and forth, you need to achieve neutrality. slouchinessWhen the boat itself is on course with the released tiller.
The tension of the shackles is regulated depending on the strength of the wind: with a weak wind, the sail is placed perpendicular to the direction of the wind for maximum capture of the flow, with a strong one, the shackles are selected, and the sail lies along the diametrical plane of the boat. The ability to feel the wind and change the position of the sail comes with experience, so do not be afraid to experiment in safe conditions.
Be sure to have spare controls on board, such as an oar or motor, as the sail is only an auxiliary propulsion. In the case of a calm or sudden squall, you should be ready to quickly remove the sail and continue the journey in the traditional way. Safety on the water is above all else, and no fuel economy is worth the risk to life.
For initial tests, stick a flag or a lightweight cloth ribbon on the mast, which will help you visually determine the direction of the wind relative to the sail, which is critical for properly adjusting the angle of attack.
Check the condition of all components and fasteners regularly after each release. The sun, salt and sand act destructively on any materials, and timely maintenance will prolong your life. home-sailCheck the places where the cables frictate against the fabric and replace the damaged areas at the first sign of wear.
The main principle of safety: sailing weapons on an inflatable boat should be designed so that at a critical load the mast falls into the water, and not overturn the boat.
Frequently Asked Questions (FAQ)
Can I use a homemade sail in a strong wind?
The use of a homemade sail in winds above 7-8 m / s is strongly discouraged, especially on inflatable boats. The design may not withstand the load, and the management of the vessel will become inefficient and dangerous.
What is the minimum area for a boat 3 meters long?
For a boat with a length of 3 meters, the optimal area of the sail is considered to be in the range of 3-4 square meters. A smaller area will not give a tangible effect, and a larger one can lead to a loss of stability and complexity in the management of the vessel.
Do I need to register a boat with a homemade sail in GIMS?
Under current regulations, small craft weighing up to 200 kg and engine power up to 8 kW (if you have a motor) are not subject to registration. However, if you install a sail, this may change the classification of the vessel.
Which is better to make a mast: wood or aluminum?
For beginners, wood (spruce, pine) is better suited, as it is easier to process, cheaper and buoyant. Aluminum pipes are stronger, but heavier and sink, which, if you lose a mast at depth, will be a problem, and the tree is easier to repair in the field.