The project of a small rowing boat, which received the name of the people Las-5It has been one of the most popular water tourism and fishing enthusiasts in the country for several decades, and its simplicity of design, materials availability and excellent driving performance have made it a model. classics of Soviet and post-Soviet self-buildingUnlike many other projects, Las-5 It does not require complex equipment or rare materials to build.
The main advantage of this design is the ability to manufacture in garage conditions with a minimum set of tools. plywood of FC or FSF 4-6 mm thick Despite its modest size, the boat has high stability and load capacity, which allows you to take on board two or three people with a full set of equipment.
Many aquatic motors see this as a great base for experimentation, and the lightness of the hull allows you to install it. electric motors Or low-power outboard motors, although originally designed as a rowing boat, and in this article, we'll go through the specifications, the nuances of material selection, and the step-by-step build algorithm so you can avoid common beginner mistakes.
Technical specifications and design features
Constructively Las-5 It's a flat-bottomed boat with a transom stern and vertical sides in the bow, and this geometry makes it as easy as possible to cut sheets and build them. Body length It is 3 meters, which is the optimal size for transportation on the trunk of a passenger car or even in disassembled form.
The width on the midfield usually varies between 1.2 and 1.3 meters, which provides sufficient stability on the water. boulder The weight of the empty hull rarely exceeds 40-50 kg, allowing it to be dragged along the shore by one or two people.
The construction has a capacity of 250-300 kg, including the weight of passengers and equipment, which is enough for comfortable fishing or cruising in calm water bodies. Sludge The boats are minimal, which allows for shallow areas and reed-covered ducts where larger vessels simply will not pass.
However, the design limitations are also important: the flat bottom makes the boat sensitive to lateral wind and turbulence above 0.5 meters. Las-5 It's not designed for open reservoirs or rivers with strong currents, but it's controlled by switches and oars, although you can install a bracket to hold the motor.
Selection of materials: plywood and lumber
The foundation of your boat's durability is the right choice of materials. plywood High-quality building plywood grade 2/2 or 1/2. the Use of low-grade material with large knots or voids inside the layers is unacceptable, as this critically reduces the strength of the case.
Particular attention should be paid to the moisture resistance of the glue. For the skin of the body, the plywood of the brand is ideal. FSF (phenol formaldehyde), which has increased moisture resistance. FC (carbamide) is less resistant to water, but when treated with epoxy, it can also be used for budget projects. The skin thickness is usually 4 mm for the bottom and 3-4 mm for the sides, if a set frame is used.
For the frame (spangouts, foreshoots, transom), hardwood wood (oak, beech, ash) or high-quality pine / spruce without knots is used. Tranza - the most loaded element, if you plan to install the engine, so it is made of plywood with a thickness of at least 15-18 mm, often with hard wood linings.
When buying plywood, be sure to check the ends of the sheets for the absence of stratification and voids. Even a small inner cavity in the plywood can become a hotbed of rotting and destruction of the side under load.
All wooden parts must be treated with antiseptics before assembly, which will prolong the life of the product several times, and do not save on impregnation, since water and sunlight ultraviolet rays are the main enemies of any wood.
Preparation of drawings and revealing details
The construction process begins long before the first job is done by the bank. theoretical And the plasma layout. Las-5 The good thing about it is that it can be broken down into simple geometric shapes, which makes it easier to transfer dimensions to the material, and you can find the drawings in specialized literature or download them from trusted sources, adapting them to your needs.
Plywood is cut with sutures and edges in mind, and it's important to place the parts on the sheet so that you minimize waste, but you also have to keep the fibers on the outer layers of the plywood in the direction that they go along the length of the part for maximum strength. Spangouts are cut from plywood or assembled from individual elements on epoxy glue with reinforcement with glass fabric.
☑️ Preparation for disclosure
When marking, use a flexible ruler or long rail to draw smooth lines on the side. Any error in the marking stage can cause the entire hull to be skewed, which will not be corrected without complete alteration. Tranza marked with the angle of the transom board, which is usually 8-12 degrees from the vertical to compensate for the different for an outboard motor.
For the exact connection of parts by the method of "stitch and glue" (stitch and glue) in the edges of the plywood drill holes in steps of 15-20 cm through them will pass copper wire or plastic screeds for temporary fixation of the skin before gluing.
Technology of assembly of the body: step-by-step instructions
The assembly of the body begins with the manufacture slipway Or a support frame that will hold the frames, and that will ensure symmetry and the right contours of the boat, that the spans are set up strictly perpendicular to the diametrical plane, and that they are fixed by the temporary connections, and the forehead and the transom are last mounted, closing the circuit.
Once the frame is installed, the skin is placed on the sheets of plywood, bends (the 4 mm plywood is easy to bend) and is fixed through the holes with wire. This step requires carefulness: the joints of the sheets must fit tightly together, and gaps are not allowed, as they will become leakage sites.
The coating connection is made by method sticker Or by using overhead slats (lapbars) from inside the casing, and the most reliable and modern method is to use a glass-reinforced epoxy resin at the seams, which creates a monolithic structure where the seam is stronger than the plywood itself.
The secret to the perfect seam
To obtain a strong connection on the mustache, the angle of the bevel must be at least 1:8 (by 1 mm plywood thickness of 8 mm of bevel length).
After removing the temporary screeds and drying the glue, the inner seams are glued with strips of fiberglass, which gives the structure additional rigidity and tightness. The outer corners are also desirable to glue to eliminate the risk of plywood stratification when hitting water or pier.
Seam plating and sealing
Sealing is a critical step in whether your boat will stay afloat or sink. epoxy It creates a watertight barrier and protects the wood from rotting, and polyester resins are not recommended because of their fragility and low adhesion to wet wood.
The process involves several layers, first applying a primer layer of epoxy, then stacking the glass fabric (usually at a density of 150-200 g/sq.m.) and soaking in resin, and it is important to expel all the air bubbles so that there are no voids. Glasswork It works as a reinforcement, preventing the spread of cracks.
Pay special attention to the corners of the transom and the junction of the side with the bottom, here the concentration of stresses is maximum, it is recommended to use additional linings or lay the fabric in two layers. Las-5 Often done with a bolt, which also serves to protect the upper edge of the side from impacts.
| Parameter | Meaning/Material | Note |
|---|---|---|
| Skin of the side | Plywood 4 mm (FSF) | 2 layers of fiberglass at seams |
| Underbody skinning | Plywood 4-6 mm (FSF) | Keel-enhanced |
| Spangouts | Plywood 10-12mm / Board | Step 400-500 mm |
| Tranza | Plywood 18 mm + bar | Inclination angle 8-12° |
| keel | Oak rail 20x40 mm | Bottom protection |
Finishing and painting
Once the carpentry is complete and the epoxy layer has been dryed, the surface of the boat needs finishing, and the epoxy is afraid of ultraviolet light, and over time it can become cloudy or covered with a fine mesh of cracks if it is not protected. painting Or varnish.
You can paint with yacht enamels or polyurethane compounds that are elastic, resistant to salt water and mechanical damage, and you have to grind the surface to a smoothness before you paint it, removing all the tar and roughness. ground-breaker epoxy improves the adhesion of the finishing coating.
The interior of the boat is often left covered with transparent varnish or painted in light colors to visually expand the space. slut (floor) which protect the skin from abrasion with the feet and allow the body to be dried after use.
Quality painting is not only aesthetic, but also the main shield of your boat from the ravages of sun and water.
The appearance of the finished boat depends largely on the accuracy of the previous stages. Smooth, well-skinned sides, smooth lines and high-quality gloss of paint speak about the skill of the owner and ensure a long service life of the product.
Operation, maintenance and modernization
Boat. Las-5 After each foray into the water, the body should be rinsed with fresh water, especially if you have been swimming in salt water, and it is better to keep the boat inverted under the canopy so that moisture does not accumulate inside and mold does not develop.
One of the most popular upgrades is the installation balloon This makes a hard boat more stable and safer, bringing it closer to the inflatable PVC, but keeping the bottom rigid for cruising, and often putting knobs in the nose to store things.
When chips or scratches appear, repairs are done locally: the damaged area is cleaned, a layer of epoxy is applied and tinted. Regular inspection of the places where the switches and transombs are attached is mandatory, since this is where the greatest vibration loads occur.
By following simple rules of operation and conducting prevention on time, you can enjoy fishing and cruising for many years. Las-5 It is a project that forgives mistakes to beginners, but rewards attentive masters with reliability and comfort.
⚠️ Attention: When operating outboard boats, never exceed the recommended power (usually up to 5 hp for the Las-5). Excess power can lead to the collapse of the transom and the boat sinking at full speed.
⚠️ Attention: Epoxy resin can spontaneously ignite when working with large volumes (more than 200-300 grams in a single container. Mix the components in small portions and use them immediately.
Frequently Asked Questions (FAQ)
Can you build a Las 5 without a slip, just on the floor of the garage?
Theoretically, it's possible, but it's not recommended. Without a slip, it's very difficult to get the symmetry of the sides and the correct position of the frames. The curved body will be worse than rowing, prowling on the course and looking unaesthetic. The simplest slipway of two parallel boards will make it much easier.
What is the maximum speed of the Las 5 engine?
With a motor of 2-3 hp, the speed will be about 6-8 km / h When installing 5-6 hp (maximum permissible) you can accelerate to 12-15 km / h. However, due to the flat bottom, the boat will not go on sliding and will go in displacement mode, creating a large wave.
How to replace epoxy resin if it is not on sale?
There is virtually no replacement for mustache gluing and seam reinforcement at home. Polyester resins are worse at gluing wood, and various sealants do not provide the necessary strength. You can use ready-made epoxy compounds for repairing boats, but pure hardener epoxy remains the gold standard.
Do I need to register Las-5 in the GIMS?
Under current Russian regulations, small vessels weighing up to 200 kg and with an engine up to 8 kW (about 10.8 hp) are not subject to registration. Since the Las-5 with equipment is usually less than 200 kg and the engines are installed weak, in most cases registration is not required, but it is advisable to carry documents for the boat and engine.