The search for a reliable and affordable fishing boat or a family holiday on the water often leads to the consideration of classic aluminum models of Soviet and post-Soviet production. Rainbow boat 51It's a boat that has earned a reputation for being an indestructible and practical boat for our latitudes, and many water-engineers are still looking for blueprints and diagrams of this vessel to restore it or build it from scratch with available materials.
In this article, we will discuss in detail the design of the case, the technical features and the possibilities of upgrading this model. aluminum-alloyThe stainless steel, from which it is made, remains relevant even in the era of fiberglass, and how to choose the right power plant for comfortable operation.
Despite the project's age, interest in this model is not fading, but is growing thanks to ease of maintenance and maintainability. Let's dive into the technical details and find out what lies behind this legendary name.
History and concept of the project
Design of small pleasure craft and fishing vessels in the USSR was conducted taking into account the mass production and availability of materials for the end user. Rainbow 51 It was one of the branches of this engineering idea, offering a balance between load capacity and maneuverability. duraluminiumThis ensures high strength with a relatively low weight of the structure.
The concept of the vessel was to use it on inland water bodies, rivers, lakes and reservoirs, and the shape of the hull was designed for calm water and a low-altitude wave, not a racing car, but a reliable “working” option for bringing a fisherman to a fishing site or a family walk.
⚠️ Note: When buying a used copy, it is critically important to check the condition of welds and the presence of corrosion, since the age of the metal can hide microcracks, imperceptible during a cursory examination.
The uniqueness of the project was its modularity and ease of assembly, which allowed enthusiasts to assemble boats even in garage conditions using ready-made drawings, and it was this accessibility that made the model popular.
Technical specifications of the body
The basis of any buoyancy is the body, and in the case of Rainbow 51, it is made according to the classic keel scheme with moderate keeliness, which provides good course stability when driving for an outboard motor. Overall dimensions allow you to comfortably accommodate 3-4 people with cargo, without losing controllability.
Use of use aluminum-magnesium alloys (most commonly AMG5 or AMG6) ensures that the case does not rust as quickly as steel, but requires careful attention to electrochemical corrosion when in contact with other metals. The thickness of the skin sheets varies depending on the load on the specific unit, which is a sign of competent engineering.
Details on alloys
The AMG series alloys have excellent weldability and corrosion resistance in sea and fresh water, but they are sensitive to overheating during welding, which can lead to a decrease in strength in the peri-seam zone.
For a visual comparison of parameters, it is worth referring to the table below, where the main data are given:
| Parameter | Meaning | Unit of measurement |
|---|---|---|
| Longest length | 4.8 - 5.0 | square |
| Body width | 1.6 - 1.7 | square |
| Height of board | 0.65 | square |
| Load capacity | 450 - 500 | kilogram |
| Hull mass | 120 - 140 | kilogram |
It is important to note that the actual weight may vary depending on the configuration and thickness of the metal used in the construction or repair. Resilience The boat allows you to feel confident on the water even when moving passengers.
Design features and layout
The interior of Rainbow 51 is organized with a focus on functionality. transom plate It is designed to be equipped with a medium-powered outboard motor, and it has a bow and aft compartments that can be used as trunks or additional buoyancy units.
Seats (banks) are usually removable or rotary, which allows you to transform the interior space for specific tasks: spinning fishing, trolling or just relaxing. Boards often have a hinge beam that protects the aluminum sheet from impacts on the dock or side of another boat.
- 🛡️ Protection of the board: The presence of rubber edging prevents chipping paint and dents.
- 🪑 Comfort: Possibility of installing soft seats on rotary seats.
- 📦 Storage: Sealed nose knobs for life jackets and tools.
The hull recruitment system is particularly noteworthy, with the hulls and stringers being made from a profile pipe or corner, which gives the structure a rigidity, allowing it to pass through shallow water at the risk of touching the bottom without catastrophic consequences for the integrity of the vessel.
When parking on the water for a long time, be sure to use transom wheels or lift the boat ashore so that the shells do not increase the weight and do not accelerate the corrosion of aluminum parts.
Selection of power unit and engine compartment
The question of “what engine to put” is a key for owners of Rainbow 51. The design of the transoil allows you to install engines with a capacity of up to 15-20 hp, but the best option for economical and quiet cruising operation are engines in the range of 5-9.9 hp. Two-stroke units It is preferable because of its lower weight, although four-strokes are quieter and more economical.
When choosing a motor, it is important to consider not only power, but also the length of the day-woot. For this model, the optimal length S (short shaft), because the height of the transan is standard. Installing an overpowered motor can lead to overfueling and burrowing of the bow at full speed, which is not safe.
⚠️ Warning: Installing a motor with a power of more than 20 hp requires a recalculation of the weight centering and may require the installation of additional hydrodynamic wings or hydrofol to go into plane with full load.
The motor is fastened through a standard bolting or bolting connection, if the traverse is equipped with appropriate holes. It is recommended (regularly check) tightening of the bolts of the mounting of the motor, since the vibration of the engine can weaken the connections.
☑️ Checking before getting on the water
Tuning and modernization DIY
Owners of Rainbow 51 often resort to modernization, wanting to improve driving performance and comfort. Installation of a hydrocompensator on the hydrowing of the motor It's the easiest way to improve the planing output and stabilize the course on a straight course, and this is especially true when you're going against wind or wave.
More complex projects involve installation stationary fuel tanks It's a handyola or a nose flungue that opens the main line to the motor, which frees up space in the cockpit and reduces the risk of splashing gasoline, and it's also popular to install windshields and sun awnings.
To improve performance, some craftsmen install additional fins or change the angle of inclination of the transom plates, but such interventions require accurate calculations. Illiterate tuning can lead to yawing boats or even dangerous dolphining.
- 🎨 Painting: Use of epoxy soils and polyurethane enamels to protect aluminum.
- 🔌 Electric: Installation of the onboard 12B network for navigation and charging of gadgets.
- 🪜 Safety: Installation of handrails and anti-slip coating on the deck.
And don't forget noise insulation, because sticking vibration insulation materials on the bottom and on the side of the inside significantly reduces the noise level from the wave and the engine, making the stay on the water more pleasant.
The main principle of tuning Rainbow 51 is not to break the weight balance. Any additions must be compensated or placed closer to the diametric plane of the vessel.
Maintenance and storage of the boat
Aluminum is a valuable material, but it needs to be maintained properly. The basic rule is: never keep the boat in water permanently unless it's treated with special anti-fouling compounds compatible with aluminum. freshwater It is a must for washing off salt and dirt, especially if you have been swimming on the sea.
Winter storage should be done in a dry, ventilated area, the boat should be turned over or mounted on keel blocks to avoid deformation of the hull under its own weight and snow load, and regular inspection of welds will help to detect incipient corrosion at an early stage.
If you find damage to the paint coating, it must be cleaned and painted immediately. Using zinc-containing soils (cold galvanizing) creates a reliable barrier to electrochemical processes.
⚠️ Warning: When washing a boat with high pressure washers, keep the nozzle at a distance of at least 30 cm from the surface so as not to damage the oxide film and paint coating.
Timely maintenance of rubber seals and lubrication of moving parts (if there are rotary seats or hinges of runduks) will prolong the life of your boat for many years.
Frequently Asked Questions (FAQ)
Is it possible to go to sea on Rainbow 51?
Outing the sea is only possible in a calm weather and in close proximity to the shore (coastal area), the design is not designed for open sea and large wave due to the height of the side and the features of the hull.
What is the maximum speed of this boat?
With a 9.9 hp engine and one passenger, the boat can reach speeds of up to 20-25 km / h. With full load, the speed drops to 12-15 km / h, which is the normal mode for displacement or transitional driving mode.
Do I need to register a boat with GIMS?
Yes, if the weight of the equipped boat with the installed engine exceeds 200 kg, or if the engine power is more than 8 kW (about 10.8 hp).
What's the best way to paint an aluminum boat?
It is best to use specialized aluminum paints on epoxy or polyurethane basis, be sure to pre-application of adhesive soil for non-ferrous metals.