In this article we will tell you how to make a sailing catamaran with your own hands. Let's say right away that the simplest catamaran for relaxing on a lake or river can be made from available materials, tightly knitting materials that float well. A homemade catamaran made from bottles is a fun design that will last a couple of days and make your weekend unforgettable.
In this article we offer more difficult option homemade catamaran. Advantages of this design:
- The main material is pine wood: available to anyone;
- one person can assemble and transport;
- spacious deck
Such a building can last for more than one season and, if assembled correctly, can replace a boat or fishing boat. Let's go directly to step by step instructions, which will help you make a catamaran with your own hands.
Frame
The main material is pine (high-quality, dry).
The frame is made up of 8 beams: 4 stringers and 4 beams (transverse).
Each one consists of two parts. Parts of different lengths: at the points of their connection they are attached subconnected (the length is selected individually - to suit the “rower”). Next you need:
- Plane the bars - 8 pcs. (40x40). The length of 4 of them is 1110, 4 – 1340.
- Connect the parts of the stringers with the corners (40x40x4) so that the middle of the corner falls on the joint of the parts. There must be a gap at the joints of the parts!
- Plane the bars – 4 pcs. (75×30 x1380). Narrow the ends to reduce weight. Place the beams on the stringers and drill.
- Podrunduchniks – stern (45x23x770) and bow (58x24x1010). The optimal fastening of the undercuts to the beams is a nail.
- Sand the wooden parts well and cover with drying oil.
Deck
Material – tarpaulin (the densest).
- By adding allowances for pockets to the length of the frame, you get the length of the deck panel. An allowance is needed for the pockets for the frames.
- We calculate the width by measuring the distance between the third and second stringers. Leave enough allowance for hem folding.
- Form pockets for medium beams. To do this, sew wide strips from the bottom.
- The holes for the bolts should be covered with a harsh thread.
- When attaching the beams to the stringers, make sure that the deck is taut.
Lockers
Materials: plywood (3 – 4 mm), wooden slats (20×15), glue, piano hinges (fastening the lids), screws.
Any thick fabric is suitable for the cover.
Precise adherence to their dimensions is necessary so that the bow locker can be easily inserted into the stern locker, simplifying transportation. Handles stretched through the holes in the sides of the smaller locker will be convenient.
Larger dimensions: 800x285x225 mm.
Oarlocks
- Can be made from steel rods (14 mm diameter is sufficient).
- Cut the rods along the axis to a depth of 7 cm and bend the “horns” to the sides.
- The swing axis will replace the nail (4 mm), the fishing line will act as cotter pins.
Sub-clavicle
Material: aluminum pipe (diameter 22)
- First, flatten the ends of the pipe.
Inserts - plates (aluminum, thickness 7).
- Attach them vertically to the corners of the stringers (first and fourth).
- Attach hingedly, but tightly (rivet).
- In a similar way, attach pipe struts (diameter 20) to the shelves. An aluminum plate clamp will do.
Floats
Material: thick tent fabric, rubber balls.
Balls are inserted into the slots of the sewn float balloon.
Dimensions: length – 3600, diameter – 400.
During production:
- Leave a hem allowance (40) and a seam allowance (60).
- To give the float the desired shape, cut out 4 stern and bow wedges (length 760).
- Attach safety tapes (for balloons) to the inner surface of the cylinder. You will then tie the ribbons from the ribbons onto the stringers.
- Leaving holes in the stern and bow for the balloon tubes, sew the edges together with strong thread.
Mast
The design of the mast directly depends on the sail model. Therefore it is necessary select after purchasing the sail. Let's just say that this catamaran will “feel” great with a 4-meter mast. It is better to make it collapsible - three sections.
Geek
Workpiece: block 30×30
- The mast manufacturing technology is repeated.
- Front end hinges are steel strips.
- Drill holes for connection to the swivel.
- Provide the rear end with pads for docking with the butt.
Nok
The manufacturing technology is repeated. Last step: equip the leg with a wire duck and a metal pulley.
Sail
Sewing sails is a special art! If you have no experience, experts advise equipping your brainchild with a ready-made sail. A sail with an area of 4 m2 can provide decent speed and sufficient safety of such a design. If necessary, you can make a simple structure from finished fabric.
Pul
Main materials: pine (bars), plywood 10, steel cable, sheet steel 1.7.
The stand with the rudder components is pulled through a corner to the frame (the horizontal shelf of the same corner is secured with screws). Additionally equip the rack cable braces.
Connect the rudder post and the stock shaft with corner loops. Pass the wire turning axle through their holes. From three plates (each thickness is 1.7) you can rivet the movable part of the stock.
The rotary pen is prepared from a sheet of 1.5 duralumin.
Centerboard device
- Make a beam from corners (duralumin) measuring 35×35 and 30×30.
- Carefully saw through the holes for the bracket suspension tenons.
- The bracket can be riveted from several profiles.
- Make guy wires from 2 mm steel cable, rings and pieces of copper tube.
- To cover the centerboard, take a 2 mm duralumin sheet.
- Select the groove at the bend with a round file with a diameter of 5 mm.
- Rivet the “tail” part. Using plywood pads, reinforce the centerboard and insert a console (made from a vaulting pole).
- Connect the casing to the console with rivets.
- Glue the foam fairings into the daggerboard, after wrapping them in gauze soaked in epoxy.
- Connect the centerboard with the bracket pivotally.
All dimensions are given in millimeters.
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A catamaran is a type of vessel that is made using two or more structurally integrated hulls. This type of watercraft is especially suitable for fishing, sports, tourism and entertainment purposes, gaining access to various hard to reach places. The sailing catamaran, reliable and safe thanks to its design features. Moreover, you can not only buy it, but also make it yourself.
Why make sailing catamarans with your own hands?
In addition to sailing ones, catamarans with a motor engine and with rowing pedal propulsors are common. They are also suitable for making on our own. Especially if you take into account the fact that buying a ready-made catamaran costs several times more than the cost of making it yourself. But many start building a catamaran on their own not so much out of savings cash, how much because of the desire to express in your brainchild original author’s ideas regarding form, design, constructive solutions, achieving certain qualities of the vessel that are not available in the proposed industrial or other designs available on the market.
In any case, no matter how difficult the work of building sailing catamarans with your own hands may seem at first glance, this is a very real and achievable task for a person who is more or less skilled and has skilled hands. Therefore, below we will look at the main stages of building a sailing catamaran. Precisely sailing because it does not have to be subject to mandatory registration with the State Inspectorate for Medical Information (GIMS), which is required for almost any small boat with a motor engine.
Choosing a catamaran design
The first thing you must decide when starting to build a catamaran is to choose its basic design, namely, what its hulls will be made of. They can be made of plywood, boards, water bottles, pipes, etc. The sailing one has a great advantage inflatable catamaran, the float bodies of which are made of rubberized material. It is this design that allows you to get a collapsible sailing catamaran.
Design requirements
The design of a catamaran depends significantly on the purpose for which you are building it. It’s one thing to use it for recreation and fishing on a small quiet lake, quite another thing to raft it down a stormy mountain river. The requirements for the strength of the structure and its elements in these cases are radically different. The ratio of the weight of the vessel and its carrying capacity is also important. After all, the smaller it is, the easier it is to transport the vessel to the place where it is intended to be used. In terms of this indicator, there is no equal to an inflatable collapsible catamaran, for which the weight of the vessel per one crew member ranges from 4 to 10 kg, and for inflatable kayaks - 8-11 kg.
Catamaran project
Real projects exist and are available that can be implemented in conditions small apartment, using only hand tool, ensuring high mobility of the product (no parts longer than one and a half meters - can be transported for free in any public transport and on an airplane), its low weight, ease of assembly and disassembly of the structure, the necessary strength and reliability.
So, if you have finally decided to make a collapsible sailing type, then you should look in the specialized literature for drawings of sailing catamarans that correspond to your choice. Believe me, it's not that difficult.
Let's consider a sailing catamaran based on two inflatable rubberized bags, which when inflated form two “cigars” with a diameter of 40 cm and a length of 280 cm, weighing 12 kg with sails and oars, which can easily support four crew members, providing them with sufficient comfort for work and rest and fishing. Each crew member weighs only 3 kg of the boat, and the ship’s unsinkability, convenience and excellent navigability have been tested in practice by dozens of short and long trips along the rivers and lakes of the central part European territory Russia. These trips have shown that a catamaran design based on bag-type floats, which easily change their shape, overcomes obstacles and shallows much more safely, where kayak-type structures based on a rigid frame often damage the rubberized fabric, forcing repairs in the field.
Float cylinders
The main thing is to make bag-shaped cigar-shaped (inflated) float cylinders. To do this, we take fabric “500” - very durable, light and dense, with the common name “silver”, since it is equipped with a special aluminum coating. We cut out the parts of the cylinders from two pieces of fabric measuring 300 x 64 cm (two per cylinder - the lower and upper parts) and glue them together using the usual rubber glue. If there is no source material suitable size, then first we glue together such pieces from smaller pieces. We glue them together with an overlap of at least 2 cm. Subsequently, we additionally glue the resulting seams with strips of the same or less thin fabric with an overlap of 2-3 cm, first from the inside of the cylinder, then from the outside. In advance, we glue tubes with flanges for inflation from the inside of the cylinder so that the tube in the upper part is directed inside the structure of the catamaran, ensuring convenience when inflating. Lastly, glue the rear, wider part of the cylinders together, following the example of a bag of flour.
A finished balloon (not inflated) made of such fabric weighs about one kilogram. For a more durable design, cylinders can be made from so-called gas holder fabric, which is used, for example, at metallurgical enterprises in containers for storing oxygen reserves. Cylinders made of this fabric are twice as heavy, but also many times stronger than those made of silver.
Deck
The design of the sailing catamaran provides for the presence of two float cylinders made of rubberized fabric, which are combined by rigid elements available only in the upper part of the structure. They are a bolted platform (to simplify assembly) of four longitudinal slats or pipes (two per float) and four to six transverse beams. It is advisable to make the longitudinal slats from the main part up to 150 cm long and the extendable part (up to the total length of the slats up to 220 cm) from a duralumin channel. Cross beams with a length of 110 to 150 cm are made from material available to you, for example, from duralumin tubes with a diameter of up to 30 mm. The float cylinders are fastened to the platform using strong tapes (gross bands), three per cylinder, or with cables using special linings with eyelet holes glued to the cylinders. On top of the resulting platform, three air-filled swimming mattresses are tightly secured with cables - one in the bow and two (on top of each other) in the stern. The rowing crew members sit on these mattresses. They provide convenient accommodation for the crew and additional buoyancy of the vessel in the event (although this never happened) one of the floats is damaged. Under the mattresses, it is advisable to strengthen diagonally located ties and a sheet of durable fabric so as not to wet the cargo on the deck.
Steering
The catamaran is controlled using a stern-mounted cross beam feather steering wheel, made from a piece of duralumin plate measuring 23 x 48 cm. Fastening is carried out with a bolt and a wing nut, limiting the movement when raising and lowering the steering wheel with screws, a tiller and a sor-line (a cable for raising the steering wheel in small places). To prevent yaw when oaring, there is a small centerboard on the bow crossbeam, which is not needed when sailing. The steering wheel is collapsible with a removable feather.
Mast, oars and sails
It is best to make a mast from three duralumin tubes inserted into each other. Although a possible option is made of wooden rods with connecting strips. When carrying a vessel, other elements of the spar are inserted into the long parts of the mast - a gaff and a composite boom, made from duralumin or tubes of the same diameter. The mast base is fastened in the middle of the second beam, as well as by four cables with tensioning devices from the upper end of the mast to the ends of the first and third transverse beams.
The oars are also made composite, like those of a canoe.
The sailing catamaran is equipped with sails made of feather percale; they normally consist of a mainsail and a jib, total area- 7 sq. m. Such sails, installed on a mast with a total height of 360 cm, complemented by a jib, allow the catamaran to pick up speed up to 8 km/h in favorable winds. If desired, the sailing rig of the catamaran can be increased by experimenting with your own navigation experience.
Having made all the elements of the catamaran, inflated the floats and mattresses, assembled and adjusted the deck, mast, rudder and sailing equipment, you will get the result: a sailing catamaran made by your own hands is ready for use and is eager to set sail to reward you and your companions with dignity for your efforts.
At first glance, the design of the catamaran is not complicated: two inflatable floats and a frame between them. However, the few basic elements have a lot of specific nuances, knowledge of which is necessary for everyone who is interested in catamaran rafting. Having the necessary information, it is easier to choose a watercraft for the task, improve the existing model and repair it on a trip.
The vessels, united by the common name “catamaran”, are initially given tasks of varying complexity, starting with “mattress” rafting and ending with the conquest of rivers of the 6th danger category (). Each manufacturer has a different approach to solving issues of convenience and safety, which is reflected in the designs of frames, cylinders and seats.
It is definitely not possible to understand all the existing subtleties and characteristics by reading only the instructions supplied with the vessel. I will try to cover the topic of the design of a tourist catamaran in this material.
Cylinder design
Floats are the most important part of the vessel. Stability, load capacity, and driving performance depend on them. There are 2 main types of cylinders - single-layer and double-layer.
As the names suggest, we are talking about the number of layers of material that form each float - a sealed container without an internal cylinder or a two-layer structure, where the upper power shell protects the inflatable chamber.
Both types have pros and cons, and, unfortunately, are surrounded by a number of myths inspired by manufacturers.
Single layer cylinders
Lighter, more compact, quick to assemble. Made from high-quality boat PVC material, they are no less reliable than a two-layer float. Gluing during production strengthens the joints, and in the event of forced repairs, the special patch copes with its task with a bang. It is easier to repair a mono structure in the field.
Mono cylinders are also divided into internal sections, and damage to one of them will not sink the ship. Good characteristics For single-layer nacelles, German fabrics VALMEX Boat Mainstream 1000 g/m2 and Powerstream 1200 g/m2, HEYTex Boat H5559 1200 g/m2 are considered.
Valmex 1200 grams There is only one drawback of the single-layer model - the correct material for its manufacture is more expensive than for two-layer floats; this is not cost-effective for on-line production.
Double layer
The sealed inflatable layer is located inside the power shell. Such floats are heavier in dry weight, and after rafting the weight of water in the internal interlayer space is added. They are much more difficult to dry and assemble correctly - assembly can take several hours. They take up more storage space. They are no less afraid of holes than mono.
The inner container is made of lightweight material of medium strength. It partly follows the shape of the main balloon to avoid unnecessary folds, but is longer than it. Thanks to this, the chamber is not inflated with air all the way, and the lack of pressure reduces the load on the seams. The best fabrics: Finnish Viniplan 6331 boat 550 g/m2, VALMEX Boat Life raft 7326 500 g/m2.
Repair kit MEHLER PLASTEL® boat TE 70 For repairs, PVC PLASTEL boat TE 90 and TE 70 has proven itself well: they adhere well, the tensile strength of the strip is 5 cm 2800/2800N. It’s more difficult with glue; in production they use two-component ones. One of the compromise options is the French BOSTIK.
Gondola shape
The gondolas of the first catamarans had a simple cigar-shaped shape. Sewing them is not difficult, and if you want to increase the volume, you can make changes to the pattern without complex calculations.
It is convenient to attach a deck and accessories for a motor or sail to a vessel with such cylinders, so “sausage” catamarans are best choice from the point of view of tourists not looking for extreme sports.
Sports double models are sewn in the camel style. They received this name because of the “humps” on the stern and bow. At the same time, the middle part, where the rowers and luggage are located, turns out to be lower. The vessel's center of gravity also shifts down, making it more stable and controllable. In addition, the humps partially protect athletes from impacts from oncoming shafts.
Number of sections
The internal container is often equipped with partitions that divide it into several independent sections. This increases the weight of the catamaran and during assembly you will have to inflate each section separately. But, even if the ship gets a hole, there will still be a fair amount of air left in the cylinder, and the rowers will have time to moor the ship to the shore on their own.
Volume
An important characteristic on which the vessel’s carrying capacity and its ability to overcome obstacles depend. The huge float easily passes through moderately difficult barrels, and when competent work crew - dangerous foam boilers. It is not overturned by rigid shafts, in short, in any such situations such a catamaran is highly stable.
Maximum load for Urex Tourist-1: 350 kg, for Bereg K6: 1700 kg. The larger the volume of the cylinders, the lower the vessel’s ability to maneuver, so on slalom sections the tonnage boat will feel insecure.
Additional Features
- Holes for inflatable containers may have different options execution. For example, a self-closing valve (models from Raftmaster), a zipper (Baseg), piano hinges (Svarog).
- Longitudinal fasteningsSome ships have a frame lace-up, for which there are special ridges with eyelets on the sides of the cylinders through which a rope is passed. This fastening has a drawback - the rope can easily be broken, for example, by hitting a stone. Because of this, many manufacturers offer another method: corridor along the cylinder. However, the option is often suitable only for the “original” frame, so replacing a damaged pipe, for example, with a wooden picket will be problematic. For this purpose, manufacturers sometimes combine both mounts: corridor and ridges.
- Pockets, handles. For the convenience of catamaran riders, the cylinders may have separate pockets for a lifeline, pump or repair kit, as well as special handles that can be used to lift the boat or grab onto it while in the water.
- Individual tailoring. Manufacturers offer ready-made production models, but many, at the request of the customer, are ready to make changes to existing designs. So, if there are no internal partitions in the inflatable container, you can ask them to be glued in, or choose a more dense material for the bottom. Some people want to increase the flow, glue the seams, add handles. Such improvements will allow you to get a watercraft “for yourself.”
Frame
An equally important detail on which the strength of the finished structure depends. The frame of a catamaran must be light, reliable and strong so as not to break upon impact, and this quality is achieved in different ways. I'll start with the right material for the frame.
Material
Duralumin used more often than other alloys. D16T pipes are especially often recommended, providing the best strength-to-weight ratio. Titanium frames are occasionally found, but they are quite fragile and are the exception to the rule.
Tree. When making an extremely difficult cast with a long walk, many tourists prefer to make a frame in place of the slipway. Of course, this is only possible in areas where suitable young trees can be found.
Manipulating wood will take more time than assembling the “original” frame, but will significantly save the weight of transported equipment. Ready wooden structure It turns out to be durable and not very heavy, so on a catamaran you can safely pass any obstacles that the crew can handle.
The tree often helps out those who have a breakdown, because on the river there are simply no other options to repair the frame.
Shape and length
- Regular frame- These are straight sections of pipe fastened together. The lengths are attached to the sides of the gondolas and connected by cross members. Some “camels” also have a special release pipe that runs under the seat and levels the area under the rower’s knees. Its ends are clamped under the crossbars.
- Bent pipes. There are models of catamarans with curved pipes, for example, Triton's Argut. This design of the frame allows you to form a balloon and increase the rigidity of the structure, but has a number of disadvantages. One of them is the inability to repair the frame while camping.
- Long valleyshave two versions: straight pipes and bent ones. They increase the rigidity of the cylinder, thanks to which the catamaran holds its course better and cuts the shafts. However, when diving into a barrel from a steep drop, the hard bows dig deep, and the water can push the catamaran onto the bow candle. In turn, hard food, once under the drain, transfers force to the entire frame, which again can result in a stern candle.
- Short valleysare only straight. The ends of the bow and stern of such catamarans are soft, so the bows “float” in the barrel, saving the ship from a candle and capsize, and the stern under the drain sinks and pushes out. But the price to pay for stability in barrels will be less controllability.
Frame assembly methods
Rigid bolted connection. The cross members and lengths are bolted together, so the frame is rigid. The catamaran becomes as obedient as possible and reacts to all actions of the crew members, however, such a frame is unstable to deforming loads.
Other disadvantages of such a connection: the bolts can bend, thereby complicating assembly and disassembly, and sometimes get lost, so it is better to put a few twists in the repair kit for a catamaran with a rigid frame, just in case.
Bolt and twist Flexible connection on twists. The twisted frame is easier to assemble: the connecting elements are strands with an aluminum collar secured with a cuff. Another option is ordinary strips of rubber cut from old car inner tubes. I even saw a bamboo frame, twisted with only adhesive tape.
The twisted frame turns out to be soft, forgives significant deformations, neutralizes impact energy, but the vessel responds to the actions of the rowers with a slight delay.
Solid and collapsible cross members
The valleys are long, so they are divided into two halves. This does not affect the strength of the frame, since significant stress does not occur at the joints. But with crossbars experiencing different types loads, it’s not that simple.
Solid pipe more reliable than a collapsible one, but powerful water can break anything, so there is no point in depriving yourself of convenience.
Collapsible crossbars. The reason for their appearance is related to the convenience and rules of baggage transportation, which are becoming more and more strict. Many tourists decided on a collapsible design - the package with oars and frame becomes shorter and easily fits on the third shelf.
This measure complicates the assembly and there is a risk of cutting off the bolts on the rainforests sticking out of the water.
In general, the design is catching on, and on water routes you can increasingly see watercraft with collapsible cross members. Some tourists thought of moving the connection point from the center closer to the cylinder, where the load on the frame is less.
Seats
The number of seats is ideally equal to the number of rowers and a multiple of two, since the crew is distributed equally across both cylinders. But options are also possible: on the “Latvian” double, the seats are located between the gondolas.
With mattress rafting, it is permissible to place passengers on backpacks. On difficult routes, the rower's seating must ensure safety and comfort, so the seats are pre-sewn to the outer skin, or are rigidly fixed in place.
Stiffness of the legs in the knee position— an unresolved problem of rafting on catamarans. In stretch areas you will be able to rest by straightening your legs, but even getting off the kata onto the shore can sometimes be difficult.
The concept of convenience is individual for each catamaran operator, but only one thing is certain - the seat should be high enough to reduce the load on the knees.
Found on sport catamarans two types of seats: “machine guns” and more familiar inflatable ones:
- "Machine guns" received such an unexpected name because of the support, reminiscent of a machine gun bipod. The design is quite convenient, it will not deflate at the wrong moment, but widespread not received and is perceived as exotic.
- Inflatable seats or cans, more popular. They are easier to assemble, convenient and have only one drawback - if the plug accidentally falls out, the seat will deflate. However, this rarely happens, and in all other respects the device showed its best side.
Knee supports- an essential part of the seats; they hold the rower in place, preventing him from falling out and allowing him to operate the oar without difficulty. With the free end they are attached to the lengths and are adjusted depending on the needs and dimensions of a particular person.
Belraft catamarans even have two straps on each side, but only people with above average height can truly appreciate such convenience.
Fixing straps able to hold the leg in different places: for some it is more convenient for them to be located as close to the body as possible, but there are also those who prefer support on the middle of the thigh. Such moments are individual and each athlete adjusts the straps to suit himself, fortunately catamaran manufacturers provide this opportunity.
An additional detail on the stops is a self-release buckle, like the Raftmaster models. It is needed to free yourself during a rollover if protection or other elements of equipment get caught in the belts.
Additional details
A deck or awning is found on most tents and heavyweight models; I have even seen tents on decks. Water-repellent luggage bags are also required.
The possibility of installing a sail and a removable transom for the motor would not hurt. In a word, there is no limit to perfection, and as long as catamarans exist, their designs will be modernized.
It is unlikely that it will be possible to create a universal vessel suitable for all types of rafting, but existing models have every chance of becoming better.
And on a full-flowing river, and a small lake, and on a pond, a homemade catamaran will become not only fun, but also useful device. You can sunbathe on it, jump into the water from it, because it is almost impossible to turn it over. You can use your homemade catamaran to transport small loads, and also sail to inspect the fish cages. If you create a flotilla of such vessels, then it is quite possible to organize small competitions in speed or figure driving; they will also become an excellent means for making a small tourist trip.
What are we dealing with?
In order to assemble a catamaran with your own hands, you do not need any special materials - they are all available and very easy to process. If you don't take into account metal elements, then you will need ZMM plywood and slats with a section of 15-25 and 25 * 25 millimeters and a length of 3 meters. This is the main advantage of the resulting raft, as well as its feature. It is best to use If this does not turn out to be the case, then it is better to purchase birch, however, even in its absence, it is permissible to use spruce or aspen.
If you seriously decide to make a catamaran with your own hands, then choosing plywood is a very important step, because the durability of your craft will depend on it. Naturally, it is also important to show diligence in terms of careful finishing of individual parts, as well as their connections. The plywood should be soaked while heated. It is best applied on a hot sunny day using a wide brush. Heating of drying oil should be done exclusively in a water bath using a wide bowl of boiling water. Of course, it is important to remember to be careful, because a burn from a hot substance is quite painful. You can complete the impregnation operation after the drying oil stops being absorbed into the wood. Typically, application is carried out two to three times with intervals of several hours.
Structural elements
So, when understanding the question of how to make a catamaran, it’s worth considering everything in order. The raft's pontoons are made of slats and plywood. It’s worth starting with the frames. To do this, you need to cut 12 blanks from plywood, the dimensions of which are 320 * 320 millimeters, knock them down with three or four nails, and then process everything together along the contour. Next you need to make slots for the slats. The slats are square, but the slots should be 20-25 millimeters in size. The remaining 5 millimeters in the slats are equipped with grooves. It is best to lay all six slats side by side, secure them, and then use a saw to make cuts in all of them at the same time. Since they will turn out to be a little deeper at the edges, it is worth leveling the average depth by shifting the boards several times during the work process.
Before forming grooves, it is worth checking the dimensions of the plywood sheets. If we are talking about a number less than 1500 millimeters, then it is necessary to adjust the installation location of the cross member 7 and frame 5 accordingly. Six frames require pieces of slats to be attached to them from the sides and top, and a piece of board should be attached to the bottom. Everything must be done as firmly as possible; it is better to use screws or screws for this, because nails will be driven into the slats, the task of which will be to hold the plywood.
Vessel assembly
If you decide to make a catamaran with your own hands, you will need to prepare several slats. The length of four of them should be three meters each, two should be 1.9 meters each, you will also need four segments of 570-600 millimeters each, after which you can proceed to further work. It is clear that it is worth placing a pair of upper slats below, which will allow the frames to sit firmly in their place. You can immediately fasten a couple of cross members with screws, and then lay the keel rail, screwing it to frames 1, 5 and 6. Next, you can turn the catamaran frame on its side to secure the upper rails to the same frames.
You will need a board 50 millimeters thick to cut out the stern and bow bosses, and here it is important to take into account that their shape should be cone-shaped. And then they need to be inserted into place, having first tied the top slats with wire. On the bow and stern overhangs, the keel rail is made from several scraps.
Sheathing
Now it's time for this important element like cladding. To make a catamaran with your own hands, you need to cut out several elements. The width of the central part is 823 millimeters, cutting it out is not difficult. It is easy to bend it to the shape of the frame, since it has already been impregnated with drying oil. But it’s important not to rush here. To make the work easier, you need to tighten the workpieces with wire, ropes or something else, and then leave them in this position for several days. It is worth noting that plywood should be fastened with nails, but it is first necessary to coat the fastening points with thick paint on the slats, frames, and also in the corresponding places of the plywood. Most diligently you should coat the joints on the frames.
Continued assembly
If you are making a catamaran with your own hands, the drawings have already been carefully thought out, then further on cardboard template you should determine the shape of the blanks for the overhangs. This should look like a cone. They are installed similarly to the previous elements. The plugs should only be attached to the paint. Their contours should be specified based on the finished skin. The 9-11 slats should be nailed to the paint, like all other parts. Next, you can cut out the deck by tracing the outline of the almost finished pontoon. Once the deck is nailed down, the pontoons can be completed. During the installation process, you should not skimp on paint.
Deck
The easiest way is to make it from the same plywood as the other parts. For strength from below and above, it is worth nailing the slats in increments of 300-350 millimeters. If you don't trust the strength of plywood, you can lay it in two layers, stacking one on top of the other. Where the pedals will be installed, it is necessary to adjust the rack pitch accordingly. Naturally, speaking about how to make a catamaran, it is worth noting that it is appropriate to use other materials for the deck, for example, thin boards that will be nailed so that there is a meter wide space between the pontoons.
Working part
If you decide to make a catamaran with your own hands, then the propeller drive should be made from parts from a bicycle. You will need to use a pair of frames with carriage assemblies and pedals. The cut ends of the frames should be flattened and then attached to the deck rail using screws. Spacer bushings, the length of which is 120-130 millimeters, must be installed between the pedals, and the pedals themselves must be connected by long common pins.
Equipped with paddle wheels, which are made from bicycle wheels. The blades should be cut out of rubber, the thickness of which is 4-6 millimeters, and then tied with wire to the knitting needles. One wheel should be equipped with five to six blades.
Functional area
The seat is made of plywood and slats, the cross-section of which is 25*25 millimeters. The seat is secured to the deck after the propeller drive is installed - so that the slats below are not accessible to the tensioned chain. It is best to fasten the elements with screws, since it is quite possible that the position will need to be adjusted.
So, you make a catamaran, the photo of which you liked. Next you should make steering, this will also require slats and plywood. The dimensions of the handlebars are 200*320 millimeters. A plywood bracket with sides of 200*200 millimeters should be nailed to the right one using slats, and then a rod should be sent from it to the lever, which should be installed on the side, in the immediate vicinity of the seat. The axes of the longitudinal and transverse rods can serve as thick nails, for which holes must be drilled with a drill, otherwise the rods may burst.
Final stage
There should not be any particular difficulties in assembling the catamaran. The pontoons must be installed on a level place, after which you can lay a deck on them, mark the installation locations for bicycle frames with pedals, a rowing drive and a seat. But there is no need to rush to secure all these knots. All wooden parts of the raft must be painted in three layers oil paint. Since each layer takes a day or two to dry, you will need a week for this operation.
When painting is completed, all components should be installed in place. The seat is mounted at the end. To tie the catamaran to the pier and to make it easy to carry, it is worth screwing 4-6 door handles on its sides.
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. Basic load-bearing element frame - a 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 to 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, it reverse side cover with two layers of sealant 51-G-10, 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 maintained 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 imparting 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 propeller instead of a propeller. And finally, create an attachment that does not require dismantling the wheels.
A. SAFRONOV, Gorky