The Soviet-era metal flat-bottoms are still afloat, and Progress 4 This boat, which rolled off the assembly line of the Kherson Shipyard, became a legend due to its maintainability and accessibility, but for the modern owner, it becomes a key parameter when choosing transport for transportation and launching. hull.
The question of how much weighs Progress 4It doesn't have a single answer, because the factory and the real numbers can vary significantly. The final figure is influenced by many factors: the presence of the pendant, the thickness of the metal in the particular production series, the number of paint layers applied and, of course, the attachment equipment installed. Understanding the real weight is necessary not only for the selection of the trailer, but also for calculating the load capacity of the engine.
In this article, we will take a closer look at the weight specifications of the hull, compare them with their predecessors, and look at how different modifications affect the total weight of the boat, explain why the weight on the transom is so important for safety and how to correctly calculate the load before buying a motor.
Factory specifications and the mass of empty body
According to the technical documentation issued by the Kherson Shipyard, the weight of the boat hull Progress 4 It's 250 kilograms, which is often cited in reference books, but it's only true for a perfectly clean hull that just left the production line. In reality, even a new boat can weigh more because of the metallurgy and thickness of the aluminum sheets.
The main material for production is the aluminum-magnesium alloy AMg5M. This material was chosen not by chance: it has high corrosion resistance and good weldability. alloy-density The thickness of the skin can vary within acceptable limits, and the plant allowed small variations in the thickness of the bottom and sides, which, in terms of the dimensions of the four-meter boat, gave a noticeable difference in weight.
⚠️ Warning: The 250kg factory weight does not include the weight of the keelson, which was often welded separately or installed as an additional stiffness element.
Many owners are faced with the fact that when weighing on a car scale, the arrow shows 260-270 kg. This is a normal situation associated with the accumulation of residual stresses in the metal and minimal deviations from the drawing standards in the direction of increasing the thickness of the sheet. 260-270 kgIt's a safety net.
Effect of kielson and design features on weight
One of the main distinguishing features Progress 4 Compared to earlier models, there was a developed zygomatic keel, or keel, which has been a significant improvement in seaworthiness and stability on the course, but inevitably affected the weight. The kilsons themselves, made of corner and sheet aluminum, can be anywhere from 15 to 25 kilograms, depending on the length and thickness of the profile used.
Having a quilson changes the center of gravity of the boat and the distribution of mass along the length of the hull. If you plan to transport the boat in the top trunk of a passenger car, this extra weight and change in aerodynamics can become critical. Progress 2 It made it easier to get the boat by hand. quill-dress It requires more careful handling when loading.
And you also have to consider the weight of the bow bulkhead, and in later releases, the handsets have become more massive, adding extra strings to the bulkhead, all of which, unobtrusive to the eye, add about 10 to 15 kg to the dry weight, so the claim that the boat weighs exactly 250 kg is more marketing than technically accurate.
Why does the keelson weigh the boat?
The keelson is not just a strip of metal, it's a complex structure of longitudinal beams and zygomatic sheets that increase the surface area of the metal and the number of welds. Each additional weld is a moulded metal that also has weight.
Weight Comparison: Progress 4 vs. Progress 2 and 2M
To understand the evolution of the mass of aluminum flat-plugs, a comparison with its predecessors is necessary. Progress 2The, which was the direct forerunner of the fourth model, had a body weight of about 230 kg. The increase in the length of the body from 4 meters at the "two" to 4.15 meters at the "four", as well as the introduction of the quill and the strengthening of the transom led to an increase in weight of about 20-30 kg.
Modifications Progress 2M It had some reinforcements, but it didn't have the mass that the fourth model had, and the difference in weight between these modifications becomes noticeable when you're transporting it. Progress 2 It was still possible to throw two or three relatively easy to throw on the roof of the "Zhigulya", then with the help of a squatter. Progress 4 This operation required considerable physical effort or the use of an inertial winch.
Below is a table showing the comparative weight specifications of the various modifications of the Progress line:
| Model boat | Body mass (kg) | Load capacity (kg) | Length (m) |
|---|---|---|---|
| Progress 2 | ~230 | 400 | 4.00 |
| Progress 2M | ~240 | 400 | 4.05 |
| Progress 4 | ~250-270 | 400 | 4.15 |
| Progress 4 (with 30 hp engine) | ~320-340 | 400 | 4.15 |
As you can see from the table, with similar load capacity, later models became heavier, which was offset by improved wave scalability and the ability to install more powerful engines, but for the owner, this meant the need for a more powerful tractor or trailer with a good braking system.
Weight of attachments and motor
When you talk about the weight of a boat, you can't just limit yourself to the hull. Progress 4 impossible attachmentThis is a model that is designed to increase the mass of the total, and this is primarily an outboard motor, and for this model, 20 to 30 hp engines were considered optimal. Whirlwind-30, Neptune-23 import Yamaha and Tohatsu Those years.
The weight of the engine varies depending on the model and year of production, and Soviet engines were notoriously heavy. Whirlwind-30 It weighed about 53 kg. Neptune-23 Imported two-strokes of the same period could weigh from 45 to 55 kg. Four-stroke engines, which became popular later, even heavier — their weight can reach 60-70 kg for similar power.
When calculating the total weight for the trailer, be sure to add the weight of the anchor (5-10 kg), fuel tanks (1 kg per liter + canister weight) and life-saving gear. This can add another 20-30 kg to the final figure.
In addition to the motor, a significant weight is added to the anchor device, fuel tank and gearboxes. Progress 4 It should weigh at least 5-7 kg, and taking into account the chain or the phala, its mass in the assembly reaches 10 kg Fuel tank for 20 liters in the fueled state will add another 22 kg. Thus, even without the crew and cargo, the "equipped" boat weighs 80-100 kg relative to the dry hull.
Transportation: calculation of load on trailer and car
Transportation Progress 4 The total mass of the boat with the motor, equipment and trailer itself must not exceed the technically permissible maximum mass (PTM) specified in the trailer documents and in the vehicle PTS. For passenger cars of category B, the limit is usually 750 kg or 3500 kg depending on the type of trailer, but for the type of trailer, Progress 4 Light trailers up to 750 kg are more often used.
Consider a typical scenario: the boat hull (260 kg) + the vortex-30 engine (53 kg) + the equipment (40 kg) + the trailer (150 kg) totaling about 503 kg. This fits into the 750 kg limit, leaving room for fuel, anchor and personal belongings. However, if you decide to install a heavy four-stroke engine and carry a full tank of gasoline, the safety margin will decrease.
⚠️ Warning: Exceeding the permissible load on the axle of the trailer or the car porcelain can lead to breakage of the chassis, deformation of the trailer breathed and, most dangerously, loss of control on the track. Always weigh the assembled kit on the scales before long trips.
It's also important to consider the weight distribution on the trailer. A heavy motor on the transom creates a significant moment, tending to lower the trailer's breath down. To compensate for this, the boat on the trailer often has to be moved forward, which can be uncomfortable when loading. centre-up It is critical to the sustainability of the train.
☑️ Checking transport readiness
Real measurements and experience of owners
The theory is theory, but practice makes its own adjustments. Vodka forums are full of reports of real weight measurements. Progress 4. Many owners who have put their boats on an industrial scale are surprised to find figures of 280 or even 300 kg for an empty hull. What does this have to do with it?
The fact is that over decades of operation, boats are overgrown with layers of paint, epoxy resins, anti-corrosion compounds and dirt. An owner who has spent decades painting his boat "beauty" or filling leaks with lead patches could quietly add 20-30 kg of excess weight. Lead patches, popular in Soviet times for repairing holes, especially insidious ones - a small piece of lead weighs much more than aluminum.
Also, the nose is often filled with water if the drainage holes are clogged or if the tools are forgotten in the handuk. Progress 4 Always discount the "historic weight" if the seller claims that the boat weighs 250 kg, and it looks painted five times and has homemade reinforcements, feel free to add 15% to the declared weight.
The actual weight of a used Progress 4 often exceeds the factory 250 kg by 20-40 kg due to layers of paint, repairs and accumulated gear.
Frequently Asked Questions (FAQ)
Can the weight of Progress 4 be reduced to make transportation easier?
It's impossible to reduce the weight of the case substantially without breaking its integrity. Some owners are trying to cut the pendant or cut the transom slabs, but this is not a good idea. forbiddenThe only legal way to remove all removable equipment, drain the fuel and transport the boat apart from the engine and anchors.
What is the maximum weight of the engine will withstand the Progress 4 transom?
The factory recommendation limits the power of the engine to 30 hp, which corresponds to a weight of about 50-60 kg. Installation of a more powerful and heavy motor (for example, 40-50 hp) is possible, but requires mandatory strengthening of the transom and bulkhead. Without gain, a heavy motor can loosen the mounts or deform the transom on the wave.
Do you need a trailer with brakes for Progress 4?
According to the traffic rules, trailers weighing up to 750 kg may not have a braking system. Since the curb weight of the Progress 4 with a light trailer usually falls within this limit (about 500-600 kg), brakes are not formally required.
Does the year of release affect the weight of the boat?
Yes, it does indirectly. Early-production boats (late 60s to early 70s) may have had slightly different metal thicknesses because of the tolerances of the time, and later-year boats often had factory refinements and reinforcements that could slightly increase the mass compared to the first ones.
How many people do you need to raise progress 4?
To safely lift an empty body (250-270 kg), it requires a minimum of 3-4 people of strong build. With the presence of a motor and equipment, the number of people must be increased, or mechanical means must be used: winches, crane beams or specialized slipways.