The legendary Crimean series moths, produced in Nikolaev, have been the benchmark for reliability and seaworthiness among small craft for decades, but age and operation in difficult conditions often lead to dents on the bottom, deformation of zygomatic stringers and even disruption of the geometry of the transom. Richtovovovka boat Crimea This is not just a cosmetic procedure, but a complex technological process that requires an understanding of the properties of duraluminium and the specifics of the design of these vessels.
Unlike the steel analogues, AMG5M The magnesium-aluminum alloy from which the sides and bottom of the "Crimea" are made has high plasticity, but if exposed improperly can lose strength in the heating zone or mechanical overvoltage. Restoring the original shape of the body is necessary not only for aesthetics, but also to preserve driving qualities: the curved bottom creates parasitic resistance, increases fuel consumption and reduces the speed of glides.
Before you start to act, you need to make a thorough defect, and often visual damage is just the tip of the iceberg, hiding cracks in welds or microcracks in the metal. boat-twisting It begins with an assessment of the extent of the damage and the choice of a method that does not cause irreparable damage to the structure of the metal.
Features of Duraluminum Buildings of the Crimea SeriesThe design of the Krym boats (especially the Krym-2, Krym-3 and Krym-M models) is made using a longitudinal transom set, which means that the bottom skin is reinforced with longitudinal stringers and transom frames, which gives the hull a high rigidity, but complicates the process of loosening. Simple denting from the inside is often impossible due to the presence of welded profiles, which act as stiffness ribs.
duraluminiumThe material has the ability to stick to a sharp mechanical impact, becoming brittle. So the rigting must be done gradually, with constant control of the metal stress. If you overdo it and cause excessive deformation, cracks can form in the editing area, which, under dynamic loads on the water, quickly lead to depressurization.
Special attention should be paid to the area of the zygomatic stringer, the angular junction of the side and bottom, which is the most loaded knot when hitting a wave. The deformation here is critical because it changes the contours of the body. Restoring geometry in this area often requires partial digestion or the use of a specialized tool to pull the metal without thinning it.
Diagnosis of damage and preparation for workThe first step is always to clean the case of dirt, algae and oxides. Only on a clean surface can you see the actual contours of damage. To diagnose the geometry of the bottom, experienced craftsmen use a long metal ruler or flat rack, applying it along and across the body. The gaps between the ruler and the metal will indicate the areas where you want to see the geometry of the bottom. denting.
It is important to determine the nature of the damage: whether it is the result of impact on a solid object (local dent) or the result of improper transportation and storage (general deformation of contours). In the first case, local intervention is often sufficient, in the second, complex correction of the entire bottom using a slip or stops may be required.
Before starting work, remove all attachments that may interfere with access to the inside of the enclosure. If you plan to use heating (which is permissible for AMg5M only in certain temperature conditions), care should be taken to protect the adjacent elements. Thermomarkers or special pencils will help control the heating temperature, so as not to burn the metal and not reduce its corrosion resistance.
It is critical to check the welds around the damaged area, and often the impact that created the dent causes micro-cracks in the adjacent welds, and ignoring this fact will cause the boat to flow into the first outlet after the welding.
Body and board editing technology
The most common method for small dents is the use of rubber boulders and wooden hammers. The metal "Crimea" is thin enough (usually 2 mm for the bottom and sides), so the use of steel tools is strictly prohibited - it will leave indissoluble holes. The process begins at the periphery of the dent: the blows are applied in a spiral, gradually shifting to the center, which allows you to remove the stress of the metal and return it to its original shape.
For more complex cases, where access to the inside is limited or the dent has a sharp profile, the method of editing using vacuum suction cups or adhesive systems (PDR-technologies adapted for boats) is used. rift Most often it is performed in a combined way: from the inside a support plate (template) is put, and from the outside a metal precipitation is made.
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⚠️ Warning: Never try to straighten a sharp dent with one strong blow from the inside, guaranteed to break the metal or crack along the deformation radius.
If the dent is located between the frames and there is access to it, you can use small-ton hydraulic jacks with wide support pads. Pressure is created slowly, with constant control of the shape. It is important to prevent the formation of a "clap" - the effect where the metal is arched in the opposite direction and remains in this position due to residual stresses.
In cases where the zygomatic bend is deformed, local heating may be required. Aluminum changes color when heated, but not as clearly as steel. Use 250-300°C It's like the temperature limit for editing, so that you don't break the structure of the alloy, and after you do that, the heating zone has to cool down naturally, without having to cool down with water.
Use a soap solution to test geometry, rub it with a straightened area and attach glass or transparent plastic, so you can see the irregularities and waves on the surface of the metal.
Reconstruction of transom geometry
The trunk of the Krym boat is the most vulnerable part when operating with powerful engines. Constant vibration and impact loads cause the upper part of the transom to deviate from the inside of the cockpit, and the lower part to deviate from the outside, or vice versa, depending on the mounting point of the motor. transom editing It is needed if the angle of inclination of the engine has ceased to correspond to passport values, which leads to the burying of the nose of the boat or, conversely, to excessive differentiation on the stern.
Recovery of the transom often requires complete or partial digestion, especially if the deformation is large. However, in minor deviations, you can use the method of force extrusion.
The process is as follows:
- 🔧 A thrust plate is placed on the transom, distributing pressure.
- 🔧 Between the stop and the opposite wall (or temporary jumper) is installed a screw screed.
- 🔧 Gradual twisting of the nut creates a force that returns the transom to a vertical position.
- 🔧 After reaching the desired angle, fixation and, if necessary, strengthening of the structure with additional scarves is made.
If the wooden base rotted, no metal richting will help - you need to replace the filler. Metal sheets of the transom skin without the internal filler will not withstand the load from the motor and close (“slam”) when planing.
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Welding and sealing after richting
In the process of editing, especially deep dents, there is a high risk of cracks in the metal or violation of the tightness of the welds. AMG The use of gas welding or electrodes without argon for the boat hull is unacceptable due to the high risk of oxidation and low strength of the seam.
If a crack is formed during the richtting process, its edges must be drilled (to stop the spread) and divided for welding. Argonne-arc welding (TIG) allows you to obtain a seam that is not inferior in strength to the base metal, provided that the correct filler material (usually wire) is used. SvAMG5 or SvAMG6).
The table below shows the main additive materials for repairing the boats "Crimea":
| Materials of the boat | Recommended wire | Wire diameter (mm) | Welding current (A) |
|---|---|---|---|
| Body and side (AMG5M) | SvAMG5 | 1.6 - 2.0 | 80 - 120 |
| Spangouts (AMG5M) | SvAMG5 | 1.2 - 1.6 | 60 - 90 |
| Tran (if steel) | WONEY'S electrodes | 3.0 | 90 - 110 |
After welding, we'll have to clean the seams and check for leaks, fill the boat with water or lather the seams abundantly and inject air into the boat under low pressure, and the appearance of bubbles will indicate defects that need to be repaired before launching.
Why can’t you cook aluminum with a conventional electrode?
Normal electrodes don't create a protective gaseous environment. Aluminum is instantly oxidized to form a refractory film that prevents metal from alloying, and the seam is porous and brittle, breaking apart when you first load it on water.
Strengthen design and prevent
The Crimean boat's richt is a great excuse not only to return to its shape, but also to strengthen its weaknesses. The factory design, while reliable, has age limits. Once the geometry is restored, it is recommended to install additional stiffness profiles in the most loaded areas: on the cheekbones, in the area where the jars are attached to the sides and in the bow, where the waves are most often struck.
Stripes from the same alloy are used to strengthen AMG5MThey're welded or riveted over the main set. It's important not to overload the boat with excess weight, so the reinforcement should be rational. For example, installing an additional bulkhead in the bow will not only strengthen the hull, but also create a compartment of unsinkable water.