Homemade water bike floats drawings. Making a catamaran from an old bicycle

Crafts enthusiasts who want to make such an attachment will need several meters of duralumin pipes and steel cable for the frame and 6-7 m2 of waterproof fabric for the floats. If you live close to a body of water, you can make purely water transport - a “water ped”, taking as a basis bicycle frame without wheels.

Originality of catamaran designs

The originality of catamaran designs is confirmed by a patent of the Russian Federation.

An inflatable boat, as a weekend craft, simply must be light, compact, easy to use, and bring pleasure, not trouble. At the same time, reliability, seaworthiness and speed qualities should not be sacrificed. "Rotana" are completely inflatable.
An inflatable bottom meets the requirements of planing better than a fabric stretched by a keelson, since the hydrodynamic pressure is opposed by its own internal pressure.
One of the important qualities of the boat is its ability to ride waves, which is ensured by the increased diameter of the cylinder. All boats are provided with an increased reserve of buoyancy and a large number of compartments, which is a guarantee of safety in all weather conditions and situations.
All these requirements are met by the catamaran design, which, compared to the deadrise, provides amazing softness on the wave, speed, exceptional stability and increased capacity.
A Russian patent was received for the original design.

A distinctive feature of all inflatables motor boats"Rotan" is the presence of an inflatable bottom, which provides:

* Low weight of the entire set (no flooring set).
* Additional buoyancy.
* Ease of getting the boat into working condition and repacking.
* Packaging of the entire set in one volume (bag - hermetic packaging).
* Protection of the transom from impacts on stones with minimal draft.
* Output at minimum power (increased hydrodynamic quality).
* Using a self-draining cockpit system (water flows through holes in the transom area).
* Comfortable seating for passengers while driving right at the bottom.
* The fully inflatable design of the boat allows elastic deformation in large waves without the risk of breakage and is injury-proof.

Advantages inflatable boat catamaran type:

* Minimum wetted surface > low resistance to movement > higher speed. The bottom does not touch the water, therefore, the friction force against the water is minimal.
* Ensuring correct planing surface. The catamaran design allows you to set the correct planing angle.
* Aerodynamic unloading by incoming air flow under the bottom - reduces settlement and wetted surface. The inflatable bottom plays the role of a gliding surface and the incoming air flow, clamped on both sides by skegs, pushes the boat out of the water.
* Protection of the main structural elements (cylinder, bottom and transom) from impacts against stones, and the lower part of the skegs is reliably protected by several layers of fabric. This allows the catamaran to travel under its own power directly to the shore! If the protection wears out, it can be replaced.
* Increased side height provides increased seaworthiness. The height of the side consists of the diameters of the cylinder and skegs.
* Soft ride on a big wave on a dynamic air cushion. When moving from one wave to another, the air under the bottom, compressed by the skegs, plays the role of a shock absorber.
* Increased volume and number of air chambers.
* Possibility of running in shallow water - the motor with a “short” leg is raised higher than the standard position. The ship's hull does not interfere with the operation of the propeller.
* When parked on water, the space between the skegs and their shell is filled with water, acting as ballast and providing additional stability.

Inflatable catamaran Sterkh 2

Price: 30,500.00 rub.

Description and purpose: Inflatable catamaran Sterkh 2 - designed for tourist trips and trips along rivers up to 5 k.s. inclusive, and if you have the proper experience and 6 k.s. A very reliable, obedient, easily controlled and maneuverable catamaran. Due to its design features, it can break through barrels more easily. It is quickly assembled and disassembled - can be assembled by one person.

Design and materials: The inflatable catmaran Sterkh 2 has a two-layer gondola design. The outer, power shell, which protects the internal gas-containing shell from damage and gives the catamaran its shape, is made of PVC material with a density of 850 g/sq.m for the bottom and 700 g/sq.m. m for deck and wedge. The inner shell is a rubberized fabric with a density of 400 g/sq.m.
If necessary, as an option, you can glue in a partition dividing the cylinder into 2 containers, as well as strengthen and glue the bottom seams. 2 seats with slings under the knee harness are sewn to the skin. The frame is secured through pockets. The frame consists of longitudinals - 4 pieces (length 2.0 m), crossbars - 3 pieces (length 1.8 m) and a 2-piece release pipe (length 1.48 m).

The lengths are 40 mm (wall thickness 1.5 mm), cross members 42 mm (wall thickness 1.5 mm). The method of fastening the lengths of the frame allows you to use pipes up to 50 mm, threading them into pockets, or use your own (for example, wooden poles), lacing it through the eyes of sewn slings.

Technical characteristics: number of seats 2 load capacity 350 kg volume of floats 1300 cubic meters. cm weight (without frame) 18.5 kg length 390 cm width 200 cm

Contents: seat gondolas (sewn to the gondolas) 2 pcs seat cylinders 2 pcs gondola cylinders 2 pcs passport packaging bag frame cover for frame twist 12 pcs

Tourist cruising catamaran

The most typical representative of this family is the Albatross catamaran, designed by V.M. Peregudova. Specifications here. The main feature of this design is the so-called “lunar mobility”. Those. on the wave, each corps independently plays the wave.

This leads to twisting of the bridge within acceptable limits and avoids the occurrence of strong stresses in the structure. This principle is successfully used by many designers when designing seaworthy catamarans intended for operation in coastal zone seas - from the White to the Caspian, on large reservoirs and rivers. These catamarans can sail for a long time on strong short waves without any problems with strength and controllability. But unfortunately, as many years of practice have shown, such boats cannot reach really high speeds precisely because of the insufficient rigidity of the bridge.
However, this is one of the most common types of collapsible catamarans. In tourist sailing, high speed is not the main thing. On the contrary, the greatest demands are placed on the strength and reliability of the vessel in any conditions in a given water area. Another prominent representative of this type of collapsible sailing ships is the catamaran "Fiord" designed by V.N. Pikhtarev. Specifications here.

A serious boat for serious tourists. Developed by aviation specialists and experienced tourists. Base model 1993. In 1984, the catamaran was used during a unique expedition on the Putorana plateau, where 766 km were covered by active means. Of these: sailing - 547 km - 13 days, rafting - 116 km - 5 days, walking part 103 km - 8 days. The modernized model successfully passed through Lake Baikal in 1987. From Severobaikalsk to Ust Barguzin. In May 1990, in 22 hours, the Fiord crossed the Sea of ​​Azov from Berdyansk to Kerch (170 km). Of which 4 hours the boat was drifting and 4 hours it was close-hauled at a wind speed of up to 27 m/s (11 points!).

There were no technical problems. The catamaran underwent a training program for crossing the Bering Strait. Protected by RF patents 2092372, 2046051, 2043247, 2021951. Many technical solutions used on this catamaran have now become a de facto standard when designing new boats. For example, an inflatable deck fencing. On the one hand, this element increases comfort on board, on the other hand, it serves as an emergency element of buoyancy. In 1999, one of the Fiords capsized during a severe storm on the White Sea. Thanks to the inflatable board, the crew was able to cope with the situation with minimal losses.

At the same time, the board became a kind of life raft. Another element actively adopted by designers is rigid inserts in the body, which make it possible to obtain an inflatable body with characteristics as close as possible to a rigid one. They also allow you to create a hull with a waterline length equal to the overall length. And this, as we know, is a direct path to creating a high-speed vessel - as they say in the navy, “the length runs.” Based on the experience gained, hulls were created for the serial catamaran "Albatross". Bow inserts were used to form a vertical stem and a stern insert to form the transom. Modern PVC materials that are not subject to rotting and solar radiation were used in production. Due to its strength, it allows you to increase the pressure in the body to a state where the fabric does not collapse even with significant force. When installing new hulls on a catamaran, no additional modifications are required. As a result of the tests, a significant increase in the speed of the vessel was revealed - 1.5 times on full courses and 2-2.5 times when tacking on an oncoming wave. Here it should be noted that the Albatross with standard hulls practically does not go against a strong wave in a strong wind. A short wave can simply stop it. He is forced to fall hard. The new hull allows you to walk much steeper into the wind in such weather.

Construction option number 2

Building a pedal boat so that it moves through the water using a foot drive is a very simple task. I built such structures with my comrades when I was a boy, and now I am not going to recommend them to anyone, but I only remember them with a smile. This is what they looked like...

Two five-meter logs, pointed at both ends, are floats. They are connected by several meter-long planks. In the middle part of the “bicycle” there is a low bench. In front of it is a crankshaft bent from a reinforcing rod - for a single-seater “car” there are two cranks on it with wooden pedal blocks, for a two-seater there are four. At the ends of the shaft there are wooden winged wheels with six blades. Behind the seat is a steering wheel from which two ropes extend. They control it like reins.

You can put together such a structure in two days, but any rowing boat will overtake you in sailing. Anyone who just wants to ride should build similar wheeled slow-moving vehicles. If you want to make a good fast bicycle, suitable for tourism and sports, then make it the way we suggest.

I had to work on the designs of pedal boats for many years. Moscow pioneers built the first successful systems on my advice in 1949. But since then I have been able to make a number of improvements to the design and develop new system drive. We offer you a choice of single-screw and double-screw bicycles. As practice has shown, both are good, but each has its own merits.

Depending on what material is more accessible to you, you can use slats and plywood to build floats, or, even better, sheet duralumin 0.5 - 0.8 mm thick, but not too hard.

First let's get acquainted with wooden structure. The set of floats is very simple. For both floats you will need only six rack-stringers with a length of 3500 mm and a cross-section of 25 X X 25 mm. Sawing them with a hacksaw from straight-grained pine or spruce boards is a long job. It is better to do this in a school workshop on an electric saw. You will also need a few shorter slats of the same cross-section.

Pedal boat - catamaran, general diagram.

Plan all the slats with a planer, cut the ends of each pair of side stringers “on the miter”. There is no need to sharpen the keel stringer. The transverse ribs - frames - will be cut in place. To do this, first tie the ends of each three stringers and insert temporary spacers. If the stringers do not have major flaws, they will bend very smoothly, forming a regular triangular figure. Place two bars 3004-320 mm long exactly in the middle between the side and keel stringers (for the tourist version, you can take 350 mm to get increased load capacity). Secure these half-frames through the stringers to the end with thin, 50-mm nails.

Stepping back half a meter from the middle frame, place the remaining frames of the same section in place. Then use shorter nails to secure the ends of the side stringers to the keel stringer. Try not to distort the structure and make the frames (sets) of both cases the same. Between the side stringers, replace the temporary spacers with beams, transverse bars that support the deck.

The lower part of the beams is straight, and the upper part is convex. They can be made from planks 80-100 mm wide and 20 mm thick. The top edge of each beam should meet flush with the frame, without forming a “step”. Even before sheathing the hulls with plywood, insert transverse solid bulkheads cut from waterproof 10 mm plywood. They, as shown in the figure, have a symmetrical pentagonal shape. If there is no thick plywood, glue the bulkheads together using two or three layers of thin plywood. Having precisely adjusted the bulkheads in place, nail them to the frame and beams with small nails. When driving nails, be sure to hold the part on the reverse side with a massive object, or, in extreme cases, an ordinary iron. The nails then go in easier and the structure does not become loose.

Place a second beam on the reverse side of the bulkhead. It is needed there to secure the deck. When the frame is assembled, fill all small gaps formed due to inaccurate fitting with a mixture of thick nitro glue and sawdust. Cover the finished sets of floats with aircraft plywood 1.5 -1.5 - 3 mm thick. At the joints of the skin pieces, insert additional half-frames and beams. Take nails no longer than 2.5 mm.

If you were unable to get plywood, the floats can be covered with thick canvas or calico in two or three layers. Paint each layer twice with oil paint and apply the next layer over fresh paint as soon as it becomes tacky. Some guys do without fabric, covering the cases with paper. But this takes a lot of glue and time.

For the pedal boat platform, two transverse bars with a cross-section of 30X70 mm, 1500 mm long each, and two longitudinal planks with a cross-section of 100X20 mm and a length of 1300 mm are required. In addition to them, you also need to place a third longitudinal block on the edge, 2 m long and with a cross-section of 40X70 mm. It serves as a support for the bike frame. For rigidity, this block must be placed on plywood or duralumin triangles - gussets. The bicycle frame is rigidly attached to the block using metal brackets. Make the staples from strip mild steel with a cross-section of approximately 3 X 25 mm. They need to be tightened with short bolts and washers. For the rigidity of the structure, it is also necessary to make two inclined extensions from the front part of the bicycle frame. For them, ordinary steel wire or thin steel cable is suitable.

The bicycle pedals and associated large sprocket can be used without any modifications. Only the chain from them will not go back, but forward, to the small sprocket, which is located under the middle bar at its front crossbar.

The small sprocket has the most complex structural unit; its design depends on the parts you have. The most The best decision- the mechanism of a large hand drill, which is covered with a metal casing. This drill, having made a wedge lining from wood, should be secured under the middle bar with two brackets made of a steel strip. The drill stop is not needed; it must be removed. For the drill axis on which the handle is placed, a bushing with a wide flange should be machined. Having drilled six holes in it and in the sprocket, rivet these parts with rivets 3-3.5 mm thick. Rivets can be made from annealed nails.

If you have a single-speed drill with open gears, then simply rivet the sprocket to the large gear, placing a spacer made of PCB or other plastic 10 - 15 mm thick. The thickness of the gasket should be such that after installation the chain runs along the sprockets without distortion.

It is possible that instead of a drill you will just have two bevel gears. In this case, in a school workshop or in the boss’s workshop, you will have to make a gear model similar to a drill. Don't use too delicate gears or a small hand drill. After all, the force of the legs, especially in a race, is quite high, and the mechanism can let you down.

An excellent propeller shaft is made from a duralumin ski pole. Try to find the longest stick so as not to make the shaft composite. Insert a 40 mm steel rod into the front end of the shaft, selecting its thickness according to the inner diameter of the tube or lightly filing it. The length of the protruding end of the rod depends on how much you have to extend the ski pole. File the end of the rod into a triangular shape so that it is securely clamped into the drill chuck, which serves as a convenient coupling between the propeller shaft and the mechanism.

To support the second end of the propeller shaft, make a streamlined bracket from a piece of 40 mm thick board. Secure it with long screws through the block and side linings made from scraps of sheet duralumin, tightening these linings with rivets or screws. At the bottom of the bracket, drill a hole the same size as the shaft. The result is a simple, but quite reliable bearing, especially if you boil bottom part bracket in a mixture of equal parts paraffin and machine oil. With such impregnation, a wooden bearing, thanks to water lubrication, works for a long time without noticeable wear. The propeller shaft will last a long time. If your pedal boat will work for many hours, then you can place a piece of a larger diameter tube on the shaft in the place that rotates in the bearing, securing its outer end to the shaft with a thin through bolt or even a wire pin with bent ends. A worn tube can be easily replaced.

Pedal boat - catamaran, how to make a propeller shaft.

Typically, when using standard drills, the gear ratio of the pedal boat mechanism is 1: 12, that is, with one revolution of the pedals, the propeller makes 12 revolutions. For such a rotation speed (about 600 rpm), a propeller with a diameter of 250 mm is suitable. It can be made of wood, metal or a combination.

For a wooden screw, prepare a straight-grained, knot-free, pine or spruce block measuring 60 X 120 X 250 mm. Having found the centers by the intersection of the diagonal on the wide planes of the workpiece, draw circles of 50 mm with a compass. These are the boundaries of the future hub. Make four transverse oblique cuts at the hub on the block with a hacksaw and carefully chop off the excess wood. Drill the hub according to the diameter of the shaft or the safety tube mounted on it, which we have already mentioned. Then, using a knife to process the blades, give them the shape shown in the drawing. The surface of the blade facing the bow should be convex, and the working surface facing the stern should be flat or slightly concave.

It is also important that at the hub the angle between the blade and the plane of rotation of the propeller is approximately 45° with a gradual transition to the end of the blade by 30°.

To secure the screw to the shaft, drill a through hole with a diameter of 3 - 3.5 mm in the hub and shaft and install a long screw or pin made of steel wire.

The propeller is usually selected for a specific engine. But we have a foot drive, and different guys have different “power” legs. Therefore, we indicated the average screw sizes. It is best to make three propellers of different diameters, different blade widths and pitches (the angle of rotation of the blades). Then they can be changed depending on the “engine” or sailing conditions. For the race on short distance you can install a propeller with a large diameter and a large pitch (steep rotation of the blades). For hiking, it is better to install a smaller propeller, which will lead to a slight decrease in speed, but will not tire you out when pedaling for a long time.

Treat each screw after the knife with a file, then with fine sandpaper, soak in hot drying oil, dry in the sun and paint. To work well, the propeller also needs a fairing. It can be cut out of soft wood, a piece of foam plastic and, having drilled a recess in it for the end of the propeller shaft, glue it with nitro glue to the rear plane of the propeller hub. The diameter of the base of the conical fairing must be equal to the diameter of the hub.

Previously, we installed stern rudders on pedal boats with a complex and not very reliable system of steering cables. Then we tried to use the front rudder and made sure that it worked quite well, although it was in a free flow, and not in an accelerated jet from the propeller. For the steering wheel you need a rectangular piece of WATER-RESISTANT plywood or millimeter-sized duralumin measuring 450X200 mm. Round the corners of this rectangle. At a distance of 150 mm from the front edge, make two overlays from strips of plywood or duralumin (each of three layers 80, 60 and 40 mm wide) to create a streamlined profile. Secure the trims with several rivets, insert a strip of plywood 80 mm wide into the gap above the rudder blade and rive them together. Insert two blocks made of wood or plastic into the bicycle fork, drill the blocks and a “puff” of strips so that the lower edge of the handlebars is 30 mm below the keels of the floats. The axle can be used as usual, from the front hub bicycle wheel. But do not tighten the nuts too tightly so that the steering wheel can be raised at the shore. With the handlebars in place, drill a hole for the locking cross pin at the top rear corner of the flat stock. While on the move, this pin will prevent the handlebars from moving back and will not interfere with the rise of the handlebars before pulling the bike ashore.

The connection of the upper structure of the pedal boat with the floats is made with wooden pins (dowels), inserting them into the holes at the ends of the cross bars of the platform and in the protruding edges of the float bulkheads. You need eight of these pins in total. Much more convenient are bolts that have “wings” instead of nuts - nuts with flat ears.

Now let's talk about some design changes that a young shipbuilder can make.

If you have sheet duralumin, not very hard, with a thickness of 0.5 to 0.8 mm, then you can rivet light and durable bodies of pedal boat floats that have the simplest internal fastenings. The pattern of duralumin sheets is shown in the figure.

For the side plating you will need strips 300 mm wide, for the deck - 400 mm. Using the dimensions indicated in the drawing, first make precise templates from paper or make markings directly on the metal. Since the length of the sheathing blanks is 3.5 mm, the sheets will probably have to be joined from shorter blanks. To do this, you need to cut the required number of strips 35 - 40 mm wide from the scraps that will remain after cutting the metal. These strips are applied with inside joints and riveted with standard aircraft rivets with a diameter of 2.6 - 3 mm. It is better to take a non-countersunk head, since it will be inside the float, and on the outside each hole needs to be countersunk (slightly drilled into a cone with a large-diameter drill) so that the rivet head on the outside of the body is countersunk. Make butt plates without reaching the edges of the workpiece by 25 mm.

Bend the edges 25 mm wide along the entire perimeter of the side trim blanks. First, rivet together the keel edges of the side plating, onto which you first place and rivet half-frames made from scraps of duralumin in the form of squares. The riveting shelf for these parts can be made 20 mm wide, and the rigidity shelf can be 10 mm wide. Trim the ends of the stiffener flanges so that they do not interfere with the connection between the sides and the deck.

Place the rivets of the keel seam frequently - at a distance of 10-12 mm from each other in a checkerboard pattern to form a two-row seam.

Pedal boat - catamaran, how to make floats.

Since the deck must have a convexity, its rigidity parts - beams - cannot be straight. After cutting out a template from thick paper for each beam, make these parts as shown in the figure. Along the arc of curvature of the deck, cut individual “festoons” on the workpiece and bend them with a wooden hammer (mallet). Having attached the beam to the deck plating, secure it at the edges, along with the duralumin strip covering the “festoons”, hand vise or small clamps. When you rivet this structure to the deck, the rigidity will be quite sufficient.

In the areas where the bike platform will be attached to the deck, rivet outer beams with a straight top edge. At the fastening points, they need to be made across the entire width of the deck and must be double, and even with an additional gasket. The fastening is the same as for the internal beams - with a strip overlay over the “festoons”.

Before riveting the deck, make a preliminary adjustment to the flanged (bent) edges of the sides. If the sides “stubborn” and do not take a smooth bend, rivet them a little with a steel hammer, placing an anvil or an old iron under the edges of the flanged strip. At the riveting point, the side line will curve more steeply.

After fitting, secure the deck to the sides with several clamps, and then with “beacon” rivets and rivet the seams.

In the middle part of the deck it is good to make a small hatch with sides and a tight-fitting lid. Then the float can be used to store clothes, tents, and food while camping. A hatch is also needed to make the float more durable and airtight. To do this, pour two liters of oil or enamel paint into it and, shaking it in different directions, tilting it from side to side, make this paint spread inside over the entire skin and fill the seams. To remove excess paint, you need to drill a small hole in the end of the deck and let it flow into the second float, and after processing it, in the same way, back into the can. The drain holes can simply be filled with putty. But it is better to plug them with pegs so that the water can be drained. Water in the floats is formed when they fog up, when the deck is heated by the sun, but the river is still cold.

Aluminum floats can be painted with any paint. But when swimming in sea water, it is recommended to first coat them with two thin layers of oil varnish and then paint, otherwise the metal will quickly deteriorate.

In addition to the single-screw bicycle with bevel gears in gear, we were able to design a simple and convenient double-screw bicycle. The middle longitudinal bar of the platform does not protrude beyond its limits from behind. The bicycle frame is attached in the same way as in the first version, the transmission chain also goes forward, not backward. But the larger transmission sprocket needs to be selected larger, and the smaller one - the smallest diameter in order to obtain a gear ratio of 1: 5 or even 1: 7.

The side longitudinal planks of the platform need to be made and secured more firmly, since they will support the propeller brackets. No drill or bevel gears are needed. Do you need two long and strong doors instead???

Pedal boat - catamaran, shaft mount.

Depending on which material is more available to you, for the spring or the spring from the front fork of the motorcycle. You can also use pieces of an old flexible shaft used in power tools. Springs must have a wire cross-section of at least 1.6 mm. The shaft for the small sprocket, on the ends of which springs transmitting rotation are put on, can only be made on a lathe (see figure). It should be installed on two ball bearings, on bearings made of bronze, textolite or nylon, or, in extreme cases, from hard wood boiled in oil. The birch bearing lasts about 500 hours.

This is an oblong block with holes for the sprocket shaft, for lubrication and for fastening with screws or bolts with nuts.

Place washers on the sides of the wooden bearing on the shaft, and insert cotter pins into the through holes of the shaft so that it does not move to the right and left. Flexible shafts made of springs transmit rotation at right angles to the propeller shafts, inclined under the side bars of the platform. The propeller shafts here are also good, made of aluminum ski poles, but their length is less than in the single-screw version, a little more than a meter. The figure shows that each shaft is supported by two brackets. On the front bracket, make a semicircular groove at the bottom and go around it with wire brackets along the diameter of the shaft. Place a protective tube on the end of the shaft, onto which the propeller will “sit”. The design of the bearing is just as simple, only instead of wire brackets you need to bend a plate of aluminum or brass with a groove and attach it to the bracket with rivets or screws. Be sure to place two or three washers between the propeller and this bearing to smoothly transfer the propeller stop to the bicycle. There is enough water to lubricate the washers, especially if they are made of textolite or nylon.

The bicycle handlebars are unchanged. But you will have to make two screws, with a diameter of 300 ~ 320 mm and with different directions of rotation - one with the right, the other with the left.

You can also make simplified propellers from not very rigid sheet duralumin by inserting the blades into a thickened wooden hub. Its diameter is 70-80 mm, length with a streamlined tail is 130 mm. You need to make two oblique cuts in it and secure each blade with three rivets made of soft wire with a diameter of 3-4 mm. Such propellers are convenient because the blades can be bent, choosing the most advantageous pitch. Simplified screws can also be made from wire. It is wound in an even row onto the hub tube, and then bent in the form of a contour of one and two blades. Then old nylon stockings are pulled over the outline in several layers, soaking each layer with thick nitro glue. For strength, you can make two or three wire circuits in each blade - large, medium and small. The screws are strong and lightweight. As experience has shown, a pedal boat with one propeller develops a speed of 14 km/h in calm water, and with two propellers and duralumin floats - up to 16 km! hour. This is twice the speed of a two-person pleasure boat.

Y. MORALEVICH

Motor catamarans - main features.

Yachtsmen and powerboaters around the world are conservative in their attitude towards new boat design concepts. Any model that differs in any way from the classic design is usually perceived with caution and suspicion, and sometimes with unfounded skepticism. Although this attitude has good reason, since new boat concepts are often characterized by poor engineering and design solutions.

The development of the production and operation of catamarans serves as an excellent example of the situation described above. In the last quarter of a century, much has been said about broken joints, damage to the bows of catamarans, and the problem of hard shocks when struck by large waves. Because of these inconveniences, yachtsmen were in no hurry to acquire catamarans. Many boats of this type, designed and built by amateurs, were not particularly attractive, but some examples showed good results.

Some professional boat designers saw good potential in power catamarans. From that moment on, the development of the catamaran industry began, which led to the appearance of a large number of such vessels that successfully plied sea ​​waters not only along the coastline, but also traveling across the oceans. Today, a well-designed and built motor catamaran is highly valued, confirming the significant advantages of this design compared to classic monohull vessels.

Let's look at the difference between these two types of ships.

First of all, we must remember that any design has its drawbacks. What suits one person may not necessarily suit another for many obvious reasons. However, there is a whole set of parameters by which each vessel can be characterized and measured.

Stability

Compared to a single-hull vessel, where the lifting force pushing the hull out of the water is concentrated in the middle, the double-hull catamaran has a lifting force distributed along the edges of the vessel, which ensures greater stability. Of course, there are very wide monohulls, and they are a pleasure to sail. However, their big square contact with water increases the resistance of the environment, which in turn increases fuel consumption. Also, a “flat” deadrise of a wide hull worsens its performance in waves.

Once underway, a well-designed catamaran, whether planing, displacement or transitional, provides a much smoother and more stable ride than a conventional monohull. (Note: Monohulls that are heavy or very tapered can provide a very smooth ride, but factors such as excessive rocking will negate the benefit.)

At speed, the catamaran rises, a cushion is created under it due to the flow of air and spray passing between the hulls. The greater stability of catamarans creates additional comfort when cooking, sailing long distances and allows you to get a good night's sleep.

Space

Two hulls provide more usable space inside the catamaran and on the decks. There is much more space in the bow of the ship, since there is no narrowing of the ship's hull.

The bridge deck encroaches on the living areas of the catamaran, but the creators of such vessels are finding interesting ways to turn this feature to the benefit of catamarans.

Two hulls also make it possible to better use the below-deck part of the vessel - the entire space can be occupied by sleeping places, tanks, refrigerators and storerooms.

Economical

Few owners of small boats will object to the increased efficiency of the boat. Tests and trials show that the difference in efficiency between catamarans and planing monohulls is very small. A catamaran needs a little more power to glide, but after that it consumes slightly less fuel than a monohull.

A completely different matter is catamarans with a displacement hull. Depending on the size of the hulls, catamarans are often capable of speeds in excess of 20 knots. This is one of the reasons for the prevalence of large catamaran ferries around the world, as efficiency will always be a decisive business criterion for any company.

Load capacity

Owners of the above-mentioned catamaran ferries are also well aware of their remarkable ability to carry large amounts of cargo without loss of stability or speed. Overloading a monohull turns a ship into an uncontrollable monster - a fact clearly demonstrated by events in some third world countries, where overloaded monohull ferries capsize with persistent regularity.

Privacy issues

Few people enjoy sleeping in the bows of boats (with the possible exception of couples) in cramped conditions, literally a meter apart from each other. The sounds and smells during such co-sleeping are not pleasant, to put it mildly. On power catamarans, split hulls provide greater isolation from each other during the night.

Maneuverability

From a cost point of view, the presence of two engines (one for each hull) is a factor that is not in favor of catamarans. However, in addition to providing additional safety to the boat, a "spare" engine also provides a huge advantage in maneuverability. Nothing puts people off the idea of ​​owning their own watercraft more than the fear of mooring in windy conditions on a single-engine monohull. A motor catamaran is superior to any, even a twin-engine monohull, simply because on a catamaran the engines are much further apart.

As experts joke, if you are not able to make a turn around its axis on a motor catamaran, you need to seriously think about whether it’s time to “give up” alcohol and drugs.

Splash proof

A catamaran is hard to beat in terms of protection from splashes. While underway during rough seas, the catamaran is free from the problem of the windshield being flooded with water. The two narrow hulls cut through the water with minimal splashes hitting you. While. like a monohull, even at low and medium speeds, it throws more water far to the sides and upwards, where it is carried by the wind.

Mooring, lifting out of the water and going ashore

Catamarans longer than 12 meters may have problems with lifts when stored on shore. They may be too wide for the lift, or the slings may not be long enough. At the same time, during storage, catamarans do not require lateral support; they can simply be placed on blocks. On a small catamaran with an outboard motor or an angular column, you can “poke” into the sandy shore without problems for the stability of the vessel.

Finding a place at the pier for a catamaran is usually not a problem if its width is not too large.

Price

With the same length, the cost of building a catamaran will be higher than building a monohull, since the catamaran has two hulls. But at the same time, a catamaran gives more space. Therefore, the comparison of monohulls and catamarans should be carried out not directly in length, but in the following way: a catamaran 10 meters long is equivalent in area to a boat 12 meters long, a 12-meter catamaran is equivalent to a boat 15 meters long, etc. Thus, if you take into account the deck area and interior space when buying a boat, a catamaran will cost less than its monohull brother with the same length.

Adding another engine also increases the price, but these days all powerboats and yachts over 12 meters in length almost always have two engines too

Sea trials

To finally understand what a catamaran is, you need to go to sea. When, at a speed of 20 knots and a wave of 2 meters, the spray does not fall on the windshield, your mother is calmly reading a book, and you are calmly drinking beer, without worrying that the glass will break on your teeth with the next sip - this is where the understanding comes , why catamarans will soon become the kings of the seas and oceans.

PVC is a modern material with mass positive qualities. It is quite inexpensive, lightweight, strong, durable, resistant to different climatic conditions and environments. In addition, plastic pipes are easily and quickly connected, ensuring absolute tightness of the joints.

Thanks to this, the use of plastic pipes has gained wide popularity not only in the installation of water supply and sewer systems. From these, “traditional craftsmen” use their own hands to make many useful “gimmicks”, ranging from racks and drinking bowls to sleighs and watercraft.

In this article we will tell you how you can quickly and inexpensively make a catamaran from plastic (with your own hands.

Contents of the article

Why a catamaran?

There are a lot of options for watercraft, as well as their purposes. For those who live near bodies of water, and especially for those for whom overcoming a water obstacle is a vital necessity, a catamaran is ideal. This type of vessel has many advantages. in front of kayaks, boats or yachts.

• To make catamarans from plastic pipes, a minimum amount of material is required. In addition, remnants from the recent installation of a sewer or water supply system may well be used;
• the catamaran is light in weight, so it does not cause problems in terms of transportation;
• due to the design features - two cylinders connected by a deck, such a craft has high seaworthiness, strength, reliability and sufficient speed;
• the ability to accommodate the required number of seats;
• Any type of engine can be installed on a catamaran.

What does a catamaran consist of?

The catamaran has a large number of design features compared to other watercraft.

That is why you need to know its components in detail, before starting drawings and installation work.

1. The first, and most important, part of the catamaran is the floats. These are two chamber structures located on the sides of the craft. Their immediate task is to keep the ship afloat. Cylinders can be made of different materials that limit the outer perimeter of the float. To do this, use the film from which inflatable cylinders, foam plastic or PVC pipes are made.
2. Connecting frame. It can be made of any materials, from the same plastic pipes to wood or metal. The lighter the catamaran frame, the smaller the floats can be.
3. Deck. This part is created to accommodate passengers, luggage and other things that will be transported by water.
4. Steering wheel. The function of the rudder of any watercraft is performed by an underwater blade, which for movement is directly installed parallel to the movement, and for turning it is bent in one direction or another using a rotary handle brought to the deck.
5. Oars, pedals, motor or any other device that propels the catamaran.

Vessel size calculation

The diameter of the floats, as well as the width and length of the vessel, depend primarily on where and how it will be used. The larger the crew expected and the more cargo will be transported, the larger the size of the craft and the diameter of the floats should be.

The carrying capacity of a vessel can be increased by increasing the cross-section of the cylinders or their length. The decisive factor in this situation is the volume of air inside the cylinders.

Optimal parameters for calculating floats, Based on the crew and carrying capacity the following:

• a single-seat catamaran should have a length of 2-3 meters with a cylinder cross-section of 0.3-0.4 meters;
• for the manufacture of a two-seater vessel, cylinders with a length of 3.5-4 meters and a diameter of 0.45-0.5 meters are used;
• three and four-seater watercraft have a length of up to 6 meters with a float diameter of 0.5-0.6 meters.

It is not recommended to make a catamaran longer than 6 meters, since it will almost completely lose its maneuverability. Although, if you are going to sail mainly in a straight line, there are no restrictions on the size of such a “ship”.

The larger the size of the vessel, the greater its maneuverability and stability, but the less maneuverability. This applies to both its length and width.

The width of a catamaran is primarily determined by its purpose and method of propulsion. If you are making a catamaran for river rafting using the kayak principle, its width should not exceed 1.2 meters. Otherwise, capturing water with oars becomes impossible. If it is planned to board rowers on cylinders, the width of the vessel can be increased to 2 meters.

If the catamaran is a fishing or pleasure boat and it is planned to be equipped with a sail, motor or blades with pedals, its width can be increased further.

The width of the catamaran should be at least one and a half times less than its length.

Manufacturing procedure

To make a catamaran with your own hands, you need to decide on its purpose and, based on from this, calculate the dimensions. We will consider two options for the vessel: the simplest single-seater and a tourist raft based on a catamaran.

Single catamaran

We start making the simplest single-seat catamaran by making floats. We take two pipes of the same diameter and length (based on the calculations given above, we will need plastic pipes for external sewage with a diameter of 0.4 meters and a length of 2 meters). We fix it on one side of both pipes. It will be rear end catamaran

The front part needs to be raised for greater cross-country ability and maneuverability. To do this, we use two plastic elbows with a 120 degree bend. We attach them to the other end of the pipes and also close them with plugs.

When assembling cylinders, pay special attention to the tightness of the joints. The slightest depressurization can lead to the sinking of a ship on the water.

The floats are ready. You can start assembling.

To connect the floats into one “whole” catamaran, you can use anything. Plastic pipes of small diameter are suitable, wooden blocks, metal corners, etc.

1. From the material you choose, we make crossbars 1.2 meters wide.
2. We install the cylinders strictly parallel to each other so that the bends point up and in the same direction.
3. We fix the transverse strips on top of the cylinders. For fastening, both clamps and self-tapping screws can be used, with which the transverse strips can be screwed to the floats for greater strength.
4. We install any comfortable seat on the cross beams, take the oars in our hands and row where we want.

Do-it-yourself single-seat catamaran made of plastic pipes (video)

Tourist raft

The basic principles of making these two watercraft with your own hands are not particularly different. The only difference is that the pleasure raft will obviously not be designed for one person. And it’s even better if it can also accommodate cargo in the form of provisions, a sun umbrella, clothes, dishes, and other things.

1. We make floats using the above method. But you should take a pipe with a diameter of 500-600 mm and a length of 6 meters. This will make it possible to create a stable and passable vessel on which you can take a nap without worrying about the life of the crew.
2. We make a strong frame measuring 6*2 meters. Since the frame not only must hold the cylinders in correct position, but also serve as a platform for the deck; it is better to make it from metal corners.
3. Clamps are tightened onto the pipes from which the floats are made, to which, in turn, the frame is attached using bolts.
4. Flooring is made from boards on the frame.

This design allows you to install any driving device on the catamaran, from blades driven by pedals to gasoline engines.

In addition, such a platform allows you to fully sunbathe in the sun, catch fish, and, in general, have a fun and fruitful relaxation in a narrow circle of best friends.

This may seem incredible, but with a bicycle and a backpack with a special set behind you, you can become the owner of your own catamaran. Now it will not be difficult for a cyclist to overcome almost any water obstacle.

The Italian company SBK Engineering has released a unique kit that can turn the most ordinary bicycle into a bike for riding on water in a few minutes! Of course, you won’t be able to ride on wheels on water, but you can easily turn a bicycle into a catamaran. This became possible thanks to the Shuttle-Bike kit.

The set includes two inflatable pontoons, similar to those used for splashdown on light aircraft. They also resemble an inflatable banana that tourists usually ride on on the beach. The most important thing is that a chain mechanism and an underwater propeller are installed on this entire inflatable structure.

The chain system of the pontoon is connected to the chain system of the bicycle, as a result of which the pedals will move forward through the water. Of course, adequate movement through the water would be impossible without a rudder.

The underwater rudder is connected to the front wheel, which in the “land” version performs essentially the same functions. The entire Shuttle-Bike set folds into a relatively small backpack. It only takes 10 minutes to set up the set.

The bicycle is mounted on the pontoon using special tripods. All manipulations are carried out without any special or third-party tools. Only one person is required for assembly. The whole set weighs 11 kg.

Crafts enthusiasts who want to make such an attachment will need several meters of duralumin pipes and steel cable for the frame and 6-7 m2 of waterproof fabric for the floats. If you live close to a body of water, you can make a purely water transport - a “water ped”, using a bicycle frame without wheels as a basis.

We make a catamaran from an old bicycle. Crafts enthusiasts who want to make such an attachment will need several meters of duralumin pipes and a steel cable for the frame and 6-7 m2 of waterproof fabric for the floats. If you live close to a body of water, you can make a purely water transport - a “water ped”, using a bicycle frame without wheels as a basis.

The bicycle attachment consists of a power frame, inflatable floats and a screw propeller. The main load-bearing element of the frame is the central beam, to which longitudinal beams are hingedly connected through crossbars. Front and rear folding posts are installed below, serving as spacers for the braces connecting the ends of the crossbars. The outer ends of the rear crossbars are connected by braces to the bicycle frame, keeping it from falling to its side and the crossbars from folding backwards.
To transfer the load from the load-bearing frame to the inflatable floats, trays with removable plates are riveted to the longitudinal banks from below. Inflatable floats are laced to them by the tongues or secured with fasteners.

The propulsion unit consists of a gearbox, a rowing chamber, a propeller and a steering wheel installed behind it, connected to the front fork of the bicycle with special wiring. At the ends of the central beam there are front and rear attachment points for attaching the attachment to the bicycle frame.

The design of the listed elements and their connections can be different - depending on the technological capabilities, qualifications, tastes and ingenuity of the performer.

With all the desire for constructive and technological simplicity, the author was unable to avoid turning and welding. Their use was dictated by the desire to make the mechanism as light as possible, providing it with sufficient strength and rigidity.
Power transmission. A hand-held two-speed drill with a gear ratio of 7:1 is used as a gearbox. Together with a chain drive, it provides a gear ratio between the pedal shaft and the propeller of 21:1. The drill is attached with the help of a fork mounted on the axis. Instead of a side handle, a small chain sprocket is mounted on the hexagonal shank of the drill, and the chuck is placed in the propeller shaft.

Fig.1. Bicycle catamaran

To increase efficiency, I replaced the initially used three-blade propeller 0 200 mm with a two-blade 0 270 mm glued from fiberglass with epoxy resin. Left-hand rotation screw, pitch about 230 mm. The shape and thickness of the blades are selected so that the angle of their installation changes depending on the load due to elastic deformation, providing a pitch close to optimal in all modes of movement. To simplify the design and reduce the size of the attachment when folded, I also eliminated the previously provided ring attachment around the propeller. Instead, a lighter anti-casation plate is installed, which prevents air from being sucked in.

The propeller shaft support bearing contains fluoroplastic bushings that can operate in water without lubrication (they can also be made from caprolon).

Inflatable floats are cut from rubberized fabric (“serebryanka”). To increase air tightness and protect the cotton base of the fabric from getting wet and rotting, its reverse side is covered with two layers of 51-G-10 sealant, diluted with B-70 gasoline in a ratio of 1:1.

Fig.2 Transmission and catamaran frame elements

Nylon or lavsan fabric impregnated with 51-G-10 or U-ZOMES-5 sealant, polyurethane or Moment-1 glue diluted in turpentine in a ratio of 1:1 by volume is also suitable for floats.

To attach to the cradle on the floats, tongues are glued from a strip of the same fabric 80-100 mm wide, folded as shown in the figure. It is better to glue the tongues to the inflated floats using ready-made supports and plates.

If you plan to fasten the floats with lacing, holes are made in the reeds with a diameter of 0 10 mm and a pitch of 80-100 mm, and knitting needles made of duralumin electrodes 0 3 mm are threaded into the loops of the reeds. To increase the survivability of the amphibian, each of the floats is divided into three compartments by transverse bulkheads, and in the form of conical diaphragms made of the same fabric. This shape of the diaphragms is well preserved under pressure and allows the floats to be rolled up without wrinkles. Glue the bulkheads last, leaving them in the middle part of the float open area a seam half a meter long. It is better to place the seam at the bottom.

Fig.3. Catamaran gear sprocket

It is convenient to inflate the floats with air using a rubber pump (frog). Don’t forget to glue valves with removable nipples from a rubber boat into each float compartment.

It is better to glue the ends of the floats on a block, which can be made from foam plastic, wood, papier-mâché, or clay. After gluing, all seams must be coated with sealant, then the outer seams must be sealed with strips of fabric 20 mm wide.

To increase tightness, improve appearance and impart water-repellent properties, the floats are painted with elastic paint made according to the recipe: one tube of Moment-1 glue, 0.5 liters of turpentine and 100 g of aluminum powder.
In conclusion, a few words about further improvement of the design. In principle, it is permissible to replace the drill and inclined hall with a vertical column, eliminating the steering wheel. This will reduce weight, dimensions and eliminate the need to separate the chain. It would be interesting to try to use a fin propulsor instead of a propeller. And finally, create an attachment that does not require dismantling the wheels.

Fishing becomes comfortable and effective when using swimming devices that allow you to fish anywhere in the river and quickly move around the reservoir. Catamarans for fishing are especially popular among lovers of quiet hunting.

The advantage of a catamaran is: a light weight design, it can be transported by passenger vehicles. Inflatable models are packed in a special backpack, and the non-disassembling parts are secured to the roof of the car. The models are characterized by easy movement at any speed and stability on waves.

A popular remedy for fishing— catamarans for fishing under motor. It allows you to expand the range of fishing spots, you can choose the best sites for biting. Assembling and disassembling the catamaran can be done by one person: its parts are assembled within half an hour, which makes the device mobile and convenient.

The deck is half a meter higher than the water surface, which saves fishermen from the waves, and rainfall does not accumulate inside the frame. There is no need to bail out the water; it drains into the gaps of the deck, making the catamaran easy to wash. From below, inflatable catamarans are protected by a beam from rubbing against the surface of the bottom or shore of a reservoir.

The main advantages of a catamaran-type vessel are:

• high frame stability;
• spacious and high deck;
• high load capacity;
• durable bottom;
• large air compartments;
• easy assembly and disassembly;
• easy care and cleaning from dirt;
• safety of use.

Specifications

The catamaran consists of two air cylinders and a frame, which can be inflatable or rigid, made of aluminum. When assembled, the entire structure fits in a backpack, which is convenient for transportation.

The weight of the craft often does not exceed 20 kg. Motor catamarans are heavier because they have a stronger foundation, but they also use lightweight materials in their construction. The dimensions of the products are different, they reach a length of 4-6 meters.

Sustainability

The catamaran is a stable structure; it easily rides the wave, receiving a minimum of impacts. Spray formation is small at any speed, which is comfortable for passengers. With a wave height of 0.5 m, the stability of the structure is superior to other models. Catamarans are stable on course and easily maintain a given trajectory.

The watercraft is able to withstand the influence of external forces, its lateral stability resists the forces of the turning moment. Longitudinal stability resists piles on the stern or bow - a longitudinal turning moment (turning over the stern). The large distance between the cylinders and proper weight distribution increase the stability of the product.

The safety of a catamaran is greater than that of boat models. The stability of its structure is much higher. Boat overturns are possible when there is a load on board, which often happens when fishing for fish when the craft rolls. Using inflatable structures, even several people can be on the same board without the danger of it tilting or capsizing. This craft cannot be capsized or sunk.

Usable space

Catamarans are much wider than single-hull models, resulting in almost twice the usable space of boats. Decks with a width of 2 m can be from 2.5 to 4 m long; an awning or tent is installed on a large area.

Fishermen place a table and chairs (armchairs) on the deck area, as well as fishing equipment and everything necessary for the trip. The deck is of sufficient size allowing you to move freely inside the catamaran. The models have a comfortable tension or rigid deck that can accommodate from 2 to 10 passengers.

Economical

Due to their design, catamaran models have reduced drag. Their weight is divided between the air hulls, creating little drag compared to boats. The speed of a catamaran is 20-40% higher than that of a boat with the same load.

Catamarans accelerate to 20-25 km/h when using smaller engines that consume little fuel. The fuel consumption of these models is one third lower than that of boats. Fishing models have a transom for a motor up to 10 hp, but they often use small engines from 2 to 5 hp.

Load capacity

A loaded craft can dive below the optimal depth, but overloading a catamaran will only worsen its speed characteristics: for it to sink, the cargo must be three times its carrying capacity. This means that with a carrying capacity of 500 kg, an overload of up to 1500 kg will be critical for this craft.

Catamarans have a carrying capacity of 300 to 500 kg; the load does not affect its stability and speed. Despite their light weight, the models have a large carrying capacity; they can accommodate boxes for transporting catch, fishing equipment and many other necessary loads. The number of passengers is from 2 to 10 people. Unsinkability under overload is a big advantage of the catamaran design compared to boat models.

Maneuverability

The maneuverability of the vessel is its agility when maneuvering to the right or left of the geometric center of the structure and the possibility of reverse movement. Catamaran structures have good maneuverability—quickly turning and returning to their original position. The raised bow and stern increase the maneuverability of the vessel.

Types of catamarans

Types of catamarans differ in the technical solution of the parts of the vessel:

• deck arrangements;
• installation of transverse beams for floor rigidity (beams);
• supports of different heights.

With flexible and rigid locker

The description of catamarans contains information about materials for deck construction. The locker of a catamaran can be flexible or rigid. Models with a flexible locker are easier to stack during assembly and transportation, while rigid structures are more reliable and convenient to use, but take up a lot of space during transportation.

The tension deck is made of PVC fabric, lined around the perimeter with slings with loops for fastening to the frame. The boom of these catamarans is of medium thickness, the air valve is near the stringer, and the fasteners are cross-shaped. Flexible types use polyvinyl chloride (PVC) material with a high density of 800 g/sq.m. Large cylinders can be installed on these models.

Rigid locker structures are made of boards, plywood and other dense but lightweight materials. Two supports are attached under the model, the cylinders are located on different sides of the stringer, the density of the PVC materials used is 700 g/sq.m. The supports are attached above the firmware, the air valves - above the boom. There are options with stockers, the cylinders in which are installed above the boom. On vessels with a rigid locker they fish in shallow water.

Models for two and three beams

Catamaran models for fishing have two or three beams that serve to strengthen the structure. The higher the protection of the frame, the greater the passenger capacity and other technical characteristics.

Models with two beams - for two passengers. The supports are installed at a low height. Load capacity - up to 300 kg, vessel length - up to 3.4 m, stringer diameter - 1.3 mm, cylinders - rubber patches, fastening - in the form of crosses. Can be equipped with flexible lockers. These designs are in demand among fishermen.

Catamarans with three beams are four-seater. Load capacity - up to 500 kg, air valves - near the stringer. The lockers are hard, sometimes the boom is made of rubber. Vessel options with two legs are popular. These flotation devices are made of high-density materials.

With low and high support

Supports of different heights affect the installation of motors of different power. Small models have low technical parameters, large vessels with powerful engines have higher quality characteristics.

Models with low supports are designed for installing low-power motors. Their carrying capacity is 300 kg, the air cylinders have a small diameter. It is possible to use rubber booms and ballers. The stringers are attached to PVC pads.

To use powerful motors, catamarans with high legs are produced. These models feature a rigid aluminum frame, large-diameter cylinders (density 800 g/sq.m.), and 1.4 mm thick stringers. The supports are additionally secured with braces. The length of such a catamaran reaches 4 meters.

Inflatable catamarans

When moving, the inflatable catamaran comes into contact with the water only with its cylinders; the deck and frame remain above its surface. This reduces water resistance and increases speed. Now for these structures, high-pressure cylinder chambers (250-300 mbar) are used, in the manufacture of which reinforced PVC materials are used.

The use of single-layer cylinders made of durable materials reduces the weight of the craft and increases their rigidity. Inflatable catamaran models expand the capabilities of fishermen; with their help, users of a collapsible vessel get into the most inaccessible places of the reservoir, delivering the craft to the shore using personal vehicles.

How to build a catamaran with a motor with your own hands

Only a good craftsman can construct such a craft on his own. But sometimes a do-it-yourself catamaran becomes better than the factory version; the owner has the opportunity to adjust the parameters and characteristics of the vessel to his needs.

First, the future model is designed: its detailed drawings are created, after which the general drawing is divided into separate drawings of all parts of the vessel. Then a frame is made (usually from duralumin). The next stage is the production of air cylinders from durable PVC of specified dimensions (length 3.5-4 m). The cylinders are equipped with valves for air injection.

IN homemade version You can install the stock with tension. The assembly of the structure is completed by installing the stringers and deck. An important stage of design is checking all parts of the craft for reliability. Special attention You need to pay attention to the tightness of the air cylinders. A high-quality homemade catamaran is always the pride of the owner.