The exact dimensions of Soviet metal boats are often a hot topic for owners and restorers. MCM-lengthThe numbers in the documents and in practice may vary, leading to confusion in the choice of trailer or capacity calculation, which is a deep modernization of the legendary Kazanka, retaining many of the features of the predecessor, but received a modified geometry of the bottom and transom.
For a potential buyer or craftsman who decides to restore an old enclosure, it is critical to understand the difference between the two. length and waterlineThese are the parameters that determine the performance, stability and legal status of the boat, and in this article we will examine all the nuances of sizes, based on factory documentation and real measurements of surviving specimens.
It is worth noting that metal can deform over time, and repairs with replacement sheets of skin often make their own adjustments to the geometry. Therefore, the data below are reference for the factory condition, but when buying a live boat, roulette is always necessary. The nominal length of the hull of the MCM boat is exactly 4500 mm, but the full length, taking into account the bow and stern overhangs, can reach 4600 mm.
Official data-sheet figures and reality
The manufacturer, namely the Kazan Aviation Plant named after Gorbunov, indicated in the technical documentation strictly regulated sizes. length The design was 4.5 meters, a value that was considered essential for classifying the boat as a small vessel and determining the power requirements of the motor being installed.
However, in practice, owners often encounter the fact that the roulette shows values from 4520 to 4580 mm. This is due to the technological tolerances when stamping aluminum-magnesium alloys and the features of the assembly of the case. cook-piece, such as reinforced splashers or additional hinge bars, can visually and actually increase the width and length of the vessel.
It is important to distinguish the length of waterline (DWL) and full length. For an MCM, the waterline is about 4.1 to 4.2 meters long, and that's what affects the theoretical speed and resistance of water when you're driving. If you're planning to install a motor, you should use the waterline length to calculate the glides.
When buying a trailer for transportation, be sure to consider the full size. Standard lodgings for 4.5-meter boats are perfect, but if your boat is heavily carried out turret or installed keel redane, the length may require the supports to be moved closer to the stern for proper weighting.
Evolution of sizes: comparison with predecessors
Boat. MKM (Small Kazanka Motor Modernized) replaced the model ICKThe main difference was not so much the length as the shape of the contours, the predecessor had sharper cheekbones and lower load capacity, the length of the hull was similar, but the distribution of volumes differed dramatically.
Compare the main dimensions of the modifications in the table below to see the evolution of engineering thought Kazan plant. Note that the width of the mid-spangout also increased, making the boat more roller in the parking lot, but more stable on the wave.
| Parameter | MK (1955) | MCM (1964) | MCM-RB (1970s) |
|---|---|---|---|
| Full length, mm | 4500 | 4500 | 4500 |
| Full width, mm | 1300 | 1380 | 1380 |
| Height of the side, mm | 600 | 600 | 600 |
| Body weight, kg | 130 | 145 | 155 |
As you can see from the data, length It remained the same relative to the base model, allowing for the use of existing slipways and rigs, but the hull's weight increased by using thicker sheets of skin in critical areas and increasing the set, making the boat more "unkillable," but requiring more powerful engines to get on plane.
Why didn't the length change?
The plant didn't change its length to keep up with the technology, and the length change would require reconfiguring the dies, which was not economically viable in mass production.
Effect of length on driving performance
A glitter boat with a length of 4.5 meters is characterized by a certain dependence of speed on the length of the waterline. The theoretical speed limit for a hull of this length is about 35-40 km / h when installing a motor with a capacity of 12-15 hp. Exceeding this threshold requires considerable power and often leads to the burying of the nose in the wave.
The length of the body directly affects seaworthinessThe 4.5-meter long boat is already capable of reaching open reservoirs, but it is still sensitive to lateral turbulence. The short base makes the boat squirm on the course, requiring the steering wheel to constantly monitor position.
- 🚤 planing: At a length of 4.5 m, the boat easily enters planing mode with one person and an engine from 8 hp.
- 🌊 Wave resistance: The body of such a length begins to behave uncomfortable on a wave height of more than 0.5 meters.
- ⚖️ Otheriation: The short length requires careful balancing of the load, and the shift of the passenger to the nose or stern greatly changes the angle of the trim.
Owners should remember that increasing the length of the transom sheet (motor pullout) actually increases the effective length of the waterline, but shifts the center of gravity backwards. cobbling (nose squeezing) at full speed, unless you use transom plates or hydrofoil.
When installing the motor on the boat MCM try not to take the ddvuk further than 30-35 cm from the transom. Excessive removal disrupts the centering and increases the length of the lever, which is dangerous when hitting an obstacle.
Transportability and trailer requirements
One of the key specifications that makes MKM The 4.5-meter long boat can easily be placed on standard biaxial or unaxle trailers of the MZSA type. However, the overall width with installed quad bars can exceed 1.5 meters, which requires attention when choosing a trailer track.
When preparing for transportation, it is important to consider not only the length, but also the length of the vehicle. transmatureThe MCM has a high transom, and when mounted on a trailer, the nose can pick up if the kilblocks are not properly set up. Optimally, if the kilblock is located at a distance of 1/3 of the length of the transom.
⚠️ Attention: When transporting a boat with a length of 4.5 meters over long distances, be sure to check the mounting of the nose stop. Due to the large hanging part of the nose (foreshtalk), when vibrating on the highway, there is a lever effect that can loosen the fasteners.
If you plan to keep a boat in your garage, consider that the actual length of the trailer is about 6 meters. For maneuvering in narrow garage cooperatives, this can be a problem. Some owners practice dismantling the transom plate or onboard elements, but for MCM this is rare due to the complexity of the body design.
Nuances of registration in GIMS and the length of the vessel
From a legal perspective, the length of the boat is one of the main parameters for registration, and according to current regulations, small craft weighing up to 200 kg and engine power up to 10 hp (8 kW) are not subject to registration. corpus often exceeds 140 kg, which in the sum with the engine brings the kit beyond the exempt status.
When filling a boat's role or technical data sheet, the length is specified to within a centimeter. GIMS inspectors can take a check measurement when inspecting. If the actual length differs from the passport by more than 5%, this may raise questions, although old boats usually make a discount on wear.
- 📝 Documents: The passport always indicates a length of 4.5 m If you have a homemade modification (extended), this requires re-registration as a "spoiler".
- 🏷️ Marking: On the transom or the forehead should be struck a number, next to which the model is often indicated, where the letter "M" can hint at metric specifications.
- ⚖️ Category: The 4.5-meter length of the boat is classified as either C (inland waters) or D (protected waters), but does not allow for more than 3 miles of sea without additional equipment.
☑️ Pre-registration checks
It is important to understand that when selling a boat together with a trailer, the length affects the category of driver's rights. Towing a trailer with a boat with a total weight of more than 750 kg (which is quite possible for a MCM + motor + boat bundle) may require category rights. BEAlthough in Russia, the category B is often avoided, provided that the total weight of the train does not exceed 3.5 tons.
Geometry repair and dimensional restoration
Aluminum-magnesium alloys from which it is made MKMThey have shape memory, but when they are hit hard (like a concrete pier or a stone at full speed), the geometry can be disrupted.
When restoring a boat, the question often arises: should you strictly withstand the factory 4500 mm? If you change the skin sheet completely, it is better to focus on the surviving elements of the set (spangouts). Body kit It is a frame, and the skin should lie on it, and not vice versa.
⚠️ Attention: When replacing sheets of skin, never try to stretch or compress the body to a perfect 4.5 meters by force if the frames are already deformed, which will lead to residual stresses in the metal and cracks in the welds in the first season.
If the boat has been through a fire or severe compression by ice, the length along the diametric plane may decrease. In such cases, professional repair involves the digestion of the frames. For amateur repairs, deviations of 1-2 cm are permissible, which will not have a critical impact on driving performance.
The main thing in repairs is to maintain the integrity of the power kit, not the perfect millimeters of the outer skin, the integrity of the frames is more important than the exact length of the forehead.
Can I extend the MCM boat to improve the course?
In theory, you could insert an extra section in the midfield area, increasing the length by 30-50 cm, which would improve the performance and smoothness of the boat, but legally it would turn the boat into a "spoiler" requiring a complex inspection and registration procedure with a change in design, which is rarely economically justified.
What is the real length of the water loaded MCM?
When fully loaded (3 people + cargo), the draught of the boat increases, and the length of the waterline can increase from 4.1 to 4.3 meters due to the immersion of sharp extremities.
Does the keel affect the overall length?
Yes, in pronounced keel (redane) modifications, the lowest point of the body can act as a projection of the forehead and transpant. When measuring the length for a trailer, you need to measure the horizontal projection, not the length along the surface of the metal.