A Ancient Greek ships- the best watercraft of ancient times. Wealthy trading cities such as Athens and Corinth had powerful navies to protect their merchant ships. The largest and most maneuverable ancient Greek ship was considered triremes, driven by 170 rowers. Her ram, located in the bow of the ship, punched holes in the enemy ship. But creation triremes due to the appearance of other warships, earlier built. This is exactly what my story is about.
pentekontor
In the archaic period from the 12th to the 8th century BC, the most common type of ships of the ancient Greeks were pentecontors.
Pentekontor It was a 30-meter single-tier rowing vessel, driven by twenty-five oars on each side. The width was about 4 m, the maximum speed was 9.5 knots.
Pentecontors were mostly deckless open courts. However, sometimes this ship of the ancient Greeks was equipped with a deck. The presence of the deck protected the rowers from the sun and from enemy projectiles, and also increased the cargo-and-passenger capacity of the ship. The deck could carry supplies, horses, war chariots and additional warriors, including archers, capable of withstanding enemy ships.
Original Ancient Greek pentecontors intended mainly for the transport of troops. At the oars sat the same warriors who later, having gone ashore, entered the battle. In other words, pentekontor was not a warship specifically designed to destroy other warships, but was a military transport. ( Note. Just like the Viking ships and the boats of the Slavs, on the oars of which ordinary combatants sat).
The emergence of a desire to sink enemy ships together with the troops before they land on the shore and begin to destroy their native fields contributed to the appearance on the ship of the ancient Greek device, which was called the ram.
For the warship of the ancient Greeks, which participated in naval battles using a ram as the main anti-ship weapon, the following remained important indicators: maneuverability - the ability to quickly escape from a retaliatory strike, speed - contributing to the development of impact force, and armor - protecting against similar enemy strikes.
The preservation of these characteristics nullified the calculations of the Mediterranean shipbuilders of the 12th century BC, thereby forcing the ancient Greeks to look for more rational ideas. And an elegant solution was found.
If the ship cannot be lengthened, then it can be made taller and place another tier with rowers. Thanks to this, the number of oars was doubled without significantly increasing the length ancient Greek ship. So there was bireme.
bireme
As a result of adding a second tier with rowers, security has also increased. ancient Greek ships. To ram bireme, the stem of the enemy vessel now needed to overcome the resistance of more oars.
The increase in the number of rowers also led to the fact that they were required to synchronize their actions in order to bireme did not turn into a centipede entangled in its own legs. Rowers were required to have a sense of rhythm, so in ancient times the labor of galley slaves was not used. All the merry men were civilian sailors, and received a salary during the war, like professional soldiers - hoplites.
bireme rowers
Only in the 3rd century BC, when the Romans experienced a shortage of rowers during the Punic Wars due to high losses, did they use slaves and criminals sentenced for debts who had undergone preliminary training on their large ships. The appearance of the image of galley slaves actually went down in history with the advent of the Venetian galleys. They had a different design, which made it possible to have only about 15 percent of trained rowers in the team, and the rest were recruited from convicts.
The appearance of the first bireme the Greeks are dated to the end of the 8th century BC. Birema can be recognized as the first ancient ship specially built to destroy enemy naval targets. The rowers of ancient ships were almost never professional warriors like land hoplites, but were considered first-class sailors. In addition, during the boarding action on board their ship, the rowers of the upper tier often took part in the battles, while the rowers of the lower tier were able to continue maneuvering.
It is easy to imagine that the meeting biremes VIII century with 20 warriors, 12 sailors and a hundred rowers on board with Pentekontor during the Trojan War with 50 rowing warriors would be deplorable for the latter. Although pentekontor had 50 warriors on board against 20 biremes, his team in most cases would not be able to use their numerical superiority. First, a higher board biremes would have prevented a boarding battle, and a ramming blow biremes would be twice as efficient pentekontor.
Secondly, while maneuvering pentecontors all his hoplites are oared. While 20 hoplites biremes can attack with projectiles.
Due to its obvious advantages, the bireme began to spread rapidly across the Mediterranean, and for many centuries firmly occupied the position of "light cruiser" of all major fleets. However, the place of the "battleship" two centuries later will take triremes- the most massive ancient ship Antiquity.
triremes
Trier is a further development of the idea of a multi-tiered rowing ship of the ancient Greeks. According to Thucydides, the first triremes was built around 650 BC and was about 42 meters long.
in classical Greek triere there were about 60 rowers, 30 soldiers and 12 sailors on each side. Rowers and sailors led " keleist", commanded the whole ship" trierarch».
"trierarch"
The rowers who were on the lower tier triremes, almost at the very water, were called " talamites". There were 27 of them on each side. The ports cut into the hull of the ship for oars were very close to the water, so with little excitement they were often overwhelmed by waves. In this case " talamites"retracted the oars inward, and the ports were battened down with leather patches.
The rowers of the second tier were called " zigits"and, finally, the third tier -" transits". Oars " zigits" And " transits» passed through the ports in « paradox"- a special box-shaped extension of the hull above the waterline, which hung over the water. The rhythm of the rowers was set by the flutist, and not by the drummer, as on the larger ships of ancient Rome.
The oars of all tiers had the same length of 4.5 meters. The fact is that if you look at the vertical slice triremes, then it turns out that all the rowers are located along the curve formed by the side of the vessel. Thus, the blades of the oars of three tiers reached the water, although they entered it at different angles.
Trier was a very narrow ship. At the waterline level, the ship had a width of about 5 m, and allowed a maximum speed of up to 9 knots, but some sources claim that it could reach up to 12 knots. But, despite the relatively low speed, triremes was considered a very power-armed ship. From a stationary state ancient ships reached maximum speed in 30 seconds.
Like later Roman ships, Greek triremes equipped with a buffer ram-proembolone and a battle ram in the form of a trident or head.
ram trireme
The most effective weapon of the ancient ships was a ram, and an auxiliary, but also quite effective means of armed struggle, was a boarding battle.
The success of the naval battle primarily depended on a swift strike at full speed on the side of the enemy ship, after which the crew also had to quickly reverse to change position. The fact is that the attacking ship was always at risk of attack, since it could receive more damage and get stuck in the wreckage of the oars, and therefore lose its course, and its crew would be instantly attacked by various projectiles from the side of the enemy ship.
trireme tactical maneuver - swim
One of the common tactical maneuvers during a naval battle in Ancient Greece was considered " diek plus"(swimming). The purpose of the tactical technique was to choose a course of attack that was advantageous from the point of view of the position and deprive the enemy of the opportunity to evade the blow. For this triremes moved towards the enemy ship, inflicting a glancing blow. At the same time, while passing along the side of the enemy, the rowers of the attacking ship had to retract the oars on command. After that, significant damage was inflicted on the oars of the enemy ship from one side. In a moment, the attacking ship moved into position and delivered a ramming blow to the side of the immobilized enemy ship.
Trieres did not have stationary masts, but almost all were equipped with one or two removable masts, which were quickly mounted when a fair wind appeared. The central mast was installed vertically and stretched for stability with cables. Bow mast designed for a small sail - " artemon", was installed obliquely, based on" acrotable».
Sometimes triremes modernized for transportation. Such ships were called hoplitagagos" (for warriors) and " hippagos"(for horses). Fundamentally these ancient ships were no different from trier, but had a reinforced deck, a higher bulwark and additional wide gangways for horses.
biremes And triremes became the main and only universal ancient ships Antique period from the 4th to the 5th century BC. Alone or as part of small formations, they could perform cruising functions: conduct reconnaissance, intercept enemy merchant and transport ships, deliver especially important cargo and attack the enemy on the coast.
The outcome of naval battles was decided primarily by the level of individual training of the crews - rowers, sailing crew and warriors. However, much also depended on the battle formations of the formation. On the passage, the ancient ships of the Greek fleet, as a rule, followed in the wake formation. Rebuilding in line was carried out on the eve of a collision with the enemy. Wherein ships sought to line up in three or four lines with a mutual shift of half a position. This tactical move was carried out in order to make it difficult for the enemy to maneuver " diek plus", because having broken the oars of any of the ships of the first row, the enemy ship exposed his side to the ramming of the ships of the neighboring line.
In ancient Greece, there was another tactical arrangement of ships, which in modern tactics corresponds to a deaf defense - this is a special circular formation. It was called " hedgehog”And was used in cases where it was necessary to protect ships with valuable cargo or avoid linear battles with superior enemy ships.
As ancillary ships, advice or raiders used single-tier galleys - " unirems", heirs of archaic triaccounts And pentecontors.
In the classical period of the 5th century BC, the fleet of Ancient Greece formed the basis of military power and was an important component of the armed forces of the Hellas coalitions.
Military navy of ancient greece numbered up to 400 trier. ancient ships were built at state shipyards. However, their equipment, repairs and even the hiring of rowers was carried out at the expense of wealthy Athenians, who, as a rule, became trierarchs- ship captains. At the end of the voyage trier returned for storage at the base of the navy in Piraeus, and the crew was disbanded.
Development ancient greek navy contributed to the emergence of a new category of citizens - sailors. According to their hierarchical position, they were not rich people and outside the maritime service they did not have sources of permanent income. In times of peace, when the demand for highly skilled sailors declined, they were engaged in small trade or were hired as farm laborers to wealthy landowners. Sailors who were written ashore inhabited the urban poor in Piraeus and Athens. Along with this, these were the people on whom the military power of Ancient Greece depended.
Interestingly, an ordinary worker earned about half a drachma a day, and rowers on ships and hoplites during the military campaign received 2 drachmas daily. With this money, one could buy 40 kg of grain, four buckets of olives or 2 buckets of inexpensive wine. A ram cost 5 drachmas, and renting a small room in a poor quarter cost 30 drachmas. Thus, for a month of sea wanderings, an ordinary rave could provide himself with provisions for a whole year.
Most the capital ship of the ancient Greeks, built in Antiquity, is considered a mythical tesseracontera, created in Egypt by order of Ptolemy Philopator. Sources claim that this ancient ship reached a length of 122 m and a width of 15 m, and on board were about 4,000 rowers (10 per oar) and 3,000 warriors. Some historians believe that it was rather a large double-hull catamaran, between the hulls of which a grandiose platform was built for throwing machines and warriors.
Sorry about the names Greek ships little is known. Athens had two triremes with luxurious exterior trim, which had the names " Paralia" And " salaminia". These two ships were used for solemn processions or for sending especially important orders.
In the modern world, thanks to archaeological discoveries and precise research, it becomes clear how the Ancient World was arranged, but more and more often modern humanity is convinced that ancient technical achievements and engineering solutions, especially in the field of shipbuilding worthy of admiration.
Seafaring and shipbuilding since ancient times have been advanced areas of knowledge. And this is natural, because the sea united peoples. Trade and war defined the face of the Ancient World and were often the only means of exchange not only for goods, but also for technical achievements. From archaic times, maritime dominion determined the boundaries and well-being of the kingdom and peoples, and in the era of empires it became the most important factor in power and political stability. It is not surprising that the powerful of this world have always given decisive importance to the construction of fleets.
The importance of control over maritime communications and trade was well understood by navigators. Skillful maneuvering of the fleets, the landing of soldiers on the coast, and simply the appearance of warships off the coast as a show of force - became familiar elements of the political struggle.
In the depths of centuries, the moment when the first ship was launched is hidden from modernity, but some further steps of mankind in the field shipbuilding over time, they open the curtain for humanity, creating a complete picture of the process in its final form. Researchers can argue for a long time about which rowing ships were considered the best: ancient triremes, titans of the Hellenistic fleets or galleys of the Italian maritime powers, but one thing is clear - the golden age of galleys is behind.
So how were the ancient ships built? How did shipbuilders manage to achieve such outstanding results without knowledge of hydrodynamics? To understand this, we need to realize that the technology of the ancient shipbuilding improved for many millennia until it reached its peak in the ancient era, and also the fact that shipbuilding was an art, the experience of which was accumulated over the years and passed down from generation to generation, deriving the basic laws of hydrodynamics and seaworthiness of the ship.
shipbuilding technology ancient ships is still the subject of heated debate. The stumbling block for researchers is the appearance of a ship set: frames, vertical pillars, longitudinal ties - stringers, etc. The transverse elements of the hull set exist on all ships since the boats stopped hammering or tying from bamboo. But according to what scheme were the ships built - first the skeleton or the hull?
shipbuilding technology skeleton first
shipbuilding technology skeleton first is characterized by the fact that during the construction of the ship, the skeleton of the ship was initially erected (keel, frames, stems) and only then it was sheathed with boards, creating a hull. This method is so natural that from the time of medieval galleys it has received the right to exist until now.
Recently, however, many researchers are inclined to believe that in the ancient period in the Mediterranean, ships were built differently. This method of shipbuilding is characterized in the initial execution of the skin, which, as it were, was stretched belt by belt on the frame frames prepared in advance, and only then, as the hull was ready, the ribs were inserted into it, usually in three unconnected tiers. This technique made it possible to establish serial ship building. Most likely, there was a technological chain that made it possible to create ships in large series and in a fairly short time. Examples of the construction of a whole fleet within two months are known - the fleet of the Roman consul Duilius, which brought the Romans victory at Mila in 260 BC, was built in a period of 45 to 60 days. There is also evidence of the procurement and storage of ship parts in special hangars, in which then, if necessary, a large number of ships could be assembled very quickly. There are references that the ships assembled at the shipyards were again disassembled, transported over long distances, then reassembled, making up entire fleets.
In short, there are two opposing views construction ancient ships but the truth, as they say, lies in the middle. The first skeleton first method is more economical, less time consuming and, in general, quite simple. The second shell first method is expensive and technically complex, however, thanks to this shipbuilding technology, the process was standardized, which made it possible to quickly build the required number of ships, and in addition gave another important advantage - lightening the ship's hull by one and a half times. The ship's hull fastened in this way, namely its outer part, initially has greater rigidity and does not require cross-sections of a large cross section. This, in turn, allowed more rowers to be placed in the same space. This method was used in the construction of multi-tiered large ships. For them, the advantages listed above were vital, allowing them to increase the speed by almost 30 percent, which contributed to improving the combat quality of the ship. After all, the speed of the course played a decisive role in those days in naval battles, where the only weapon of the ship was a ram. The most powerful and high-speed fleet built using this technology provided Greece with half a century of dominance at sea and allowed it to win victories over superior enemy forces. Of course, this method of shipbuilding was kept in the strictest confidence and was taken by ancient shipbuilders to the grave along with the death of the ancient world. Anyway, this shipbuilding technology was lost.
shipbuilding technology shell first
So how did shell-first technology come about? It is quite obvious that initially, small dugout boats were built without drawings - by eye. In the future, the natural desire of prehistoric shipbuilders to increase the buoyancy, capacity and floodability of the boat empirically led them to create a hull as such. At the beginning shipbuilders tried to increase the volume of the cylindrical part of the barrel. To do this, they used different methods of steaming and then expanding the hollowed out part with spacers. Gradually, such a design from a cylindrical shape was transformed into a shape close to our understanding of a boat. Over time, the collapse of the sides and the narrowing of the extremities appeared. However, very soon this development of shipbuilding reached its limit. In addition, when the cylinder was bursting, a lowering of the freeboard amidships occurred, in contrast to which they began to build on the central part of the sides of the dugout. Most likely, during the construction of such "shells" the ship arose in our remembrance of this design. All other elements appeared empirically. The keel may have arisen as a result of the desire to reduce the dugout, thereby reducing labor intensity and greatly facilitating the design. The stems were needed as elements connecting the planks of the grown side at the ends. And the rib frame, obviously, appeared when the size of the “shell” grew so much that it became necessary to fasten the outer elements from the inside.
The key point in understanding the emergence of shell first shipbuilding technology is the two methods that have existed since ancient times for connecting plating belts: clinker and smooth.
a) smooth lining; b) clinker connection;
Clinker has some advantage for early shipbuilding methods, firstly due to the greater water tightness provided by the design. Clinker is also preferable for the technology of building a hull without a preliminary skeleton and drawings. After all, in the absence of an internal frame, it is more convenient to connect the belts to each other by overlapping the strips. And most importantly, each subsequent board, lying on the previous one, repeats its curvature, using the dugout part as a tongue and groove belt, that is, a kind of template pattern.
The hull, in this case, is formed as a natural continuation of the dugout shaft, which gradually evolves into the bottom and then into the keel. Probably later, around the beginning of the third millennium BC, a method of joining belts was invented - smooth lining. Obviously, it became possible when shipbuilders began to fasten the planks with the help of original dowel plates made of harder wood.
It was the sheathing in combination with the method of fastening the belts with dowel strips, followed by fixing them with wooden pins in the upper and lower belts (the mortise and tenon method), that became the basis of the shell-first shipbuilding technology, which means - first the hull. This technique, most likely, appeared quite naturally, as they say, by trial and error and improved for several thousand years.
New construction methods required a high level of standardization of parts, competent personnel and a well-established structure of shipyards. Therefore, it is not surprising that the appearance of the first seaworthy ships is directly related to the centralization of power and the formation of ancient states.
shipbuilding method mortise & tenon
During the period of antiquity, the mortise & tenon method began to play a key role in shell-first shipbuilding technology, which replaced the “sewing” technology.
in the photo - the restored part of the hull of a merchant ship found in the 80s of the XX century in the Italian city of Comacho. This clearly shows the method of joining the belts of the outer skin of the ship. Grooves are visible at the end of the upper belt, just below the hole for dowels
The essence of the method was that at the ends of the boards of the belts, with a step of 20-50 cm, as before, grooves (mortise) were made, into which then, when docking, plates from harder tree species were inserted. However, those, in turn, were not sewn together, as before, but were pinned with pins (tenon) in the upper and lower belts. Such a pro-gelled skin was rigidly connected, and at the same time quite flexible. And most importantly, now the design was not afraid of longitudinal displacements, which inevitably led to the rupture of the stitched knots. Yes, and these displacements themselves have decreased, because soft ropes have been replaced with hardwood pins. This provided transverse and longitudinal rigidity, quite sufficient to arrange the frames less often, make them thinner and, most importantly, composite, using all the material at hand for this. Thus, the frames played the role of ribs providing only local rigidity. The overall longitudinal and transverse strength of the vessel was created by the shell-plating itself.
On large ships, beams and decking were additionally installed. It is difficult to say when such shipbuilding technology. However, it was widely used by Phoenician navigators. At that time, metal fasteners were used extremely rarely, and in relation to fastening the skin to the frames, the old stitching method was preserved.
a) fastening the skin to the frames using stitching;
b) fastening of the cladding belts to each other using the mortise & tenon method;
In the classical period, the construction of various types of ships, including the famous triremes, was put on the assembly line and honed to perfection even in the smallest details. Complicated and costly shipbuilding technology, which initially only wealthy powers could afford, was such only during the construction of the first ship. A lot of money and time was spent on the creation of technological equipment, on the standardization and unification of parts, as well as on the training and maintenance of highly qualified specialists. But then the preparation carried out, which today is called the "zero stage" in shipbuilding, fully justified itself and made it possible to build entire fleets in a short time.
Summing up, we can say that, basically, in the ancient period, ships were built according to the shell first shipbuilding technology - first the hull. Moreover, this method was based on the principle of fastening the sheathing belts flat, using the mortise & tenon method, i.e., laying adjacent planks of harder wood, which, in turn, were fixed with pins in the upper and lower parts. This technique evolved empirically from various body stitching techniques, and has been in use in the southeastern Mediterranean since at least the beginning of the third millennium BC. In the second millennium this shipbuilding technology formed the basis for the construction of powerful fleets of the peoples of the Aegean culture. At the beginning of the first millennium, this practice was already widely used by the Phoenicians, and in the classical period it acquired its final form during the construction of the Greek triremes.
shipbuilding technology shell first made it possible to build ships in large series in a very short time, and was used to create both military and transport ships. This was vital during wars or large colonization expeditions. At the same time, the construction of huge ships, such as the large ships of Caligula, was carried out according to shipbuilding technologies skeleton first - at first, the skeleton, because all the advantages of serial production in such special projects were lost, but special importance was attached to the strength of the skeleton of these giants.
A thousand years ago, in present-day Syracuse, an inventor sat in a bathtub trying to find out if the royal crown was made of solid gold. Finally, he found the answer, jumped out of the bath, and ran naked down the street, resounding the area with the now famous exclamation "Eureka". So from history, Archimedes discovered the fundamental law of physics - a force equal to the mass of water displaced by this body acts on a body partially or completely immersed in water. The weight of the body acts as a downward pressure and can counteract the upward pressure of the water; If these two forces are equal, the body floats. Thanks to the law of Archimedes, a person got the opportunity to build ships of any size from any material, and the law remains the main formula for calculating these indicators.
Modern shipbuilding technology is divided into several stages.
DESIGN PREPARATION
During the period of design preparation for production, a design of the vessel is developed. The development of a ship project, as a rule, is carried out in four stages:
1. Technical proposal
The technical proposal contains: diagrams of the general arrangement of the vessel, the midship frame, the arrangement of mechanisms in the engine room, the arrangement of special devices and the operational and economic calculation.
2. Draft design
The draft design contains drawings of the general arrangement of the vessel, a theoretical drawing, a constructive midship frame, weight load calculations.
3. Technical project
The technical project contains: contract documentation (drawings of the general arrangement of the vessel, specifications for the general ship, hull and mechanical parts, systems and electrical equipment), project documentation (drawings for the general ship and hull parts), drawings for the mechanical part (installation of main engines and shafting and piping schemes ), drawings of general ship systems, drawings of electrical equipment, calculations of strength according to the theory of the ship, weight load.
4. Working draft
The working draft contains: working drawings and all technological documentation, the volume of which is established by the shipbuilder, depending on the degree of preparedness of production, on the type and dimensions of the vessel, the size of the series and other data. The working draft includes newly developed, as well as standard, depersonalized and normalized drawings.
During the design preparation of production, the unification of equipment and materials is carried out, questions about the manufacturability of structures and the maintainability of the vessel are resolved, the method of its construction is substantiated, and the hull is divided into sections. There are several ways to assemble the ship's hull on the slipway: piece by piece, sectional and block.
With the detailed method, the body is assembled on a slipway from individual parts. The production cycle of the slipway assembly of the ship's hull in this case is very long. It is reduced by using sectional and especially block methods, which provide: dismemberment of the assembly process into preliminary and slipway; transfer of a significant part of the hull assembly work to the workshop; application of automatic and semi-automatic welding; installation of equipment in sections and blocks.
With the sectional method, a body is formed on a slipway mainly from pre-assembled planar, semi-volumetric or volumetric sections. Planar sections consist of a flat panel or with a deflection not exceeding the smaller size of the section in plan with a set of one or two directions welded to it on one side. Such sections are called semi-volumetric, in which the arrow of the deflection of the panel is less than the size of the section in the plan. Volumetric sections are considered such sections, the height of the beams of the set of which exceeds the smaller size of the section in the plan.
With the block method, the ship's hull on the slipway is assembled from ship blocks or sections blocks. The block is a part of the ship's hull, if possible, limited by structures that form closed compartments, with installed mechanisms, pipelines, and insulation. It is assembled from planar sections of the bottom, sides, deck and bulkheads, semi-volumetric and volumetric sections. When breaking down the hull into sections, production, design and technological factors are taken into account.
SHIP HULL LAYOUT AT THE PLAZA
Design bureaus usually draw ship hulls on a scale of 1:25, 1:50 or 1:100. In the manufacture of parts and hull structures according to such drawings, large-scale errors are inevitable. In addition, these drawings do not always contain all the data necessary to determine the exact shape and dimensions of parts and structures, since, for example, theoretical drawings are made only for part of the section of frames, waterlines and buttocks. Therefore, on the plaza of the enterprise, a theoretical drawing of the ship's hull is drawn in full size in three projections. Using such a drawing, they take plaza data, enter them into tables, draw sketches or make the necessary equipment for performing hull procurement, hull assembly and other work. Plasovye work is a responsible operation. Insufficient accuracy of their implementation can lead to marriage.
The plaza is a room with a specially prepared flat floor, usually made of wooden square bars or boards laid on the edge, which are cleanly planed, aligned along the shergen in all directions, primed, puttied and painted with gray oil paint. The plaza should have good natural and artificial lighting and should be kept at a constant temperature and humidity. When breaking down the hull on the plaza, a theoretical drawing of the hull, a table of planned ordinates, a drawing of the stretching of the outer skin, a diagram of the breakdown of the hull into sections and working drawings of the sections are used.
MANUFACTURING OF BODY PARTS
All body parts are divided into groups according to the principle of uniformity of operations. The following features are usually taken as the basis for classification:
the thickness of the source material;
detail contour configuration;
the presence and type of death;
the presence of cutouts and holes;
the presence of cutting edges for welding;
There are various classifiers of body parts, according to which all body parts are divided into typical classes and groups. Depending on specific conditions, some groups may be combined. Based on the accepted breakdown, the routing technology for processing parts is determined and the necessary equipment is selected. All sheet and profile metal used in the construction of ships must have a flat surface, since irregularities make it difficult to mark and cut parts, as well as assemble and weld hull structures. The deflection arrows of sheets with a thickness of 1.5-5 mm should not exceed 3 mm per meter of length, and for sheets with a thickness of 6-18 mm, up to 2.5 mm per meter of length are allowed. Profiles should not have deviations from straightness of more than 2 mm per meter and more than 8 mm for the entire length of the strip.
However, due to the presence of internal stresses caused by uneven cooling during rolling, as well as due to mechanical impacts during transportation and handling operations, sheet and profile metal supplied to factories, as a rule, is uneven, the sheets have waviness along the length, local bulges and crescent curvature, and profiles - helical curvature and waviness. Sheets and profiles, the waviness of which exceeds the allowable one, are corrected. In deformed sheets and profiles, one part of the fibers is elongated, while the other is shortened, and their editing is reduced to aligning the fibers along the length by compressing the elongated ones or stretching the shortened ones. Since it is easier to stretch the fibers than to compress them, the straightening of sheets and profiles is based on the principle of fiber tension.
Straightening is carried out manually on the plate by blows of sledgehammers, mainly of profile metal, or by mechanized methods, the most common of which is straightening on multi-roll sheet straightening rollers.
Heavily deformed thin steel sheets are dressed on a thicker backing sheet. Sometimes a backing sheet and strip gaskets are used at the same time. The technology of straightening sheets in sheet straightening rollers is regularly improved.
TECHNOLOGY OF CLEANING CASING METAL
For the preservation of ship hulls in proper technical condition during the established service life, all surfaces of hull structures must be protected from corrosion. This is achieved by their priming and painting. However, sheet and profile metal supplied to the plants is covered with mill scale and rust formed during transportation and storage. Therefore, all body metal must be cleaned.
The most productive cleaning of hull metal is by chemical and shot blasting methods.
In the chemical cleaning method, oxides are removed from the metal surface during etching in appropriate solutions.
The equipment of the metal chemical cleaning section consists of sequentially located baths filled with appropriate solutions, cassettes for loading metal into the baths and a device for drying the cleaned sheets. The chemical method of purification has not received wide distribution due to the difficulty of neutralizing wastewater. The shot blast cleaning method consists in cleaning the surface with ejected metal shot under the action of high centrifugal force. Striking, it removes dirt, rust and scale from the metal surface. After shot blasting, the metal surface acquires a clean, uniformly rough appearance.
CUTTING TECHNOLOGY OF BODY PARTS
guillotine shears
After marking the body parts with the help of templates and using a photo-projection method, the parts are cut. There are two ways of cutting body parts: mechanical and thermal. Mechanical cutting is performed on scissors - guillotine, disk, vibration and press shears.
laser metal cutting
Thermal cutting is based on the combustion of metal heated to the ignition temperature in a jet of pure oxygen and the removal of oxides formed by this jet. A combustible gas flame is used to heat the metal.
PRELIMINARY ASSEMBLY AND WELDING OF HULL STRUCTURES
Assembly and welding processes consist of several basic operations: marking the places for installing parts; primary guidance of parts and checking their position; drawing to remove allowances; combining edges and fixing parts on tacks or mechanically; welding seams and controlling their quality, as well as some additional operations: thermal cutting or pneumatic cutting when fitting to remove allowances; checking the position and control of the installation of parts and assemblies; straightening structures after welding.
The purpose of assembling hull structures is to secure the assembled parts of the structure. Welding of joints in a structure is carried out mainly by mechanized methods (automatic welding under a flux layer, semi-automatic welding in a CO2 environment and flux-cored wire, electroslag, one-sided welding with the formation of a back seam). At all stages of assembly and welding, the position (control) of parts and assemblies is checked.
POINT ASSEMBLY AND WELDING
The simplest elements of pre-assembly of the hull are nodes - technologically finished parts of the structure, from which sections or the hull of the vessel are subsequently assembled and welded. Units consist of two or more parts that make up beam, foundation, frame and bracket structures, as well as sheet panels. Their manufacture is relatively easy to mechanize and automate, especially for the hulls of flat-bottomed ships with a large cylindrical part. For the manufacture of units, depending on the degree of mechanization, there are the following methods: free assembly and welding; conductor assembly and welding; machine assembly and welding; assembly on production lines.
Free assembly of knots can be performed on universal assembly plates or simply on flat areas of the workshop. The expediency of such an assembly can only be justified by economic considerations - with a very small series of shipbuilding. In most cases, free assembly should be replaced by a conductor or machine assembly, in which labor savings are more than 40 percent. With free assembly, all operations are performed manually. With free assembly, temporary portable devices (stops, clamps, clamps) are applicable for workmanship.
Conductor assembly of knots, as a rule, they are performed without marking and tacking of elements; this eliminates the need to hold parts while aiming and checking position. The jig is a device or device that allows you to fix the details of the assembly relative to each other in the desired position, tighten and hold them from free movement during welding; strictly control the geometric parameters of the node. When assembling in a jig, welding deformations are reduced by 30 percent compared to free assembly and welding of assemblies. For large series of shipbuilding, specialized conductors are used, for small series - universal and quickly readjustable.
Machine assembly and welding of units is the most progressive. However, its implementation requires certain conditions and, above all, a sufficiently large series of products. Machine-tool manufacturing of units is characterized by high productivity, achieved due to the mechanization of operations, as well as due to the combination of assembly and welding into a single process. The specific value of mechanized operations reaches 80 percent, which makes it possible to increase productivity by more than 2 times compared to the conductor assembly.
ASSEMBLY AND WELDING OF SECTIONS
Assembly and welding of hull sections and superstructures are the main processes of ship construction. The complexity of manufacturing sections is more than half of the total complexity of assembly and welding of the hull.
The division of the hull into sections and their installation in a position convenient for assembly determined the need for such technological equipment that would create a basic support and fix the complex contours of the ship's hull, ensure the interchangeability of all sections manufactured on it. The main types of equipment for the manufacture of sections are stands and conductors, equipped with various devices and portable means of mechanization.
Production of blocks of sections. To reduce the slipway work, increase the volume of saturation with parts, assemblies and assemblies of the ship's mechanical equipment, individual planar or semi-volumetric sections and assemblies are assembled (formed) into section blocks. This type also includes superstructure blocks formed from planar sections and decks. Assembly and welding of section blocks is carried out on support devices such as keel blocks or "cages" on slipway carts and in slipway conductors. There are relatively few welding seams in the manufacture of blocks, so welding deformations are insignificant.
HULL ASSEMBLY METHODS
When building a ship, there are several ways to assemble the ship's hull.
sectional assembly of the ship's hull
The technology of shipbuilding on a slipway of planar and volumetric sections includes a set of installation and testing works. Installation work consists of operations for unfastening and moving sections, verification work - for checking the position of the structure. The significant laboriousness of these works is explained by the presence of technological allowances, which must be marked and cut on the slipway. The presence of allowances along the mounting edges makes it necessary to install and check the position of each section twice when assembling the body on the slipway (for joining after trimming the allowance).
ship hull block assembly
With the block method, the formation of a hull in shipbuilding begins with the installation of a mortgage block, which includes the engine room of the vessel, where it is necessary to perform a large amount of mechanical work. The rest of the blocks are sequentially docked to the bow and stern from the mortgage block. The formation of the hull from planar sections by compartments is a kind of block construction method. The ship's compartment, which is the most saturated with mechanisms and systems, is also taken as a mortgage. Subsequent block-compartments are formed into the bow and stern, attaching sections to the mortgage.
ring tilter
The most rational is the flow-position method of block construction of ships, which allows organizing rhythmic production.
In the construction of ships in modern shipbuilding technology, mixed sectional-block, sectional-by-piece and new methods are also used. For example, the hulls of tugs up to 53 m long are made of two halves, divided along the diametrical plane. When assembling blocks consisting of two or three sections, the assembly is carried out "board up". On the slipway, both halves are set to the required position with the help of cranes and welded along the assembly joint line. Vessels of small displacement are assembled from the most enlarged hull elements or by a monoblock method using a ring tilter.
Shipbuilding technology studies the essence of the production processes of building a ship, the relationship of these processes and the patterns of their development. It is based on such fundamental sciences as mathematics, mechanics, physics, chemistry and interacts with a wide range of applied sciences related to the creation of a ship: ship design, ship theory, ship hull strength, shipbuilding industry economics and others.
For many years, shipbuilding technology was understood as a set of production processes for building ships: obtaining and processing materials, assembling and welding hull structures and the hull as a whole, installation of mechanisms and electrical equipment, manufacture and installation of systems and devices, equipment and decoration of ship premises, testing and delivery of the finished ship to the customer. Then the concept of technology expanded significantly and, in addition to production processes, included the study and creation of technical means, the study of technical, raw materials, information, financial and human resources, management systems, social and natural environment, within which the production process is implemented, including its environmental consequences.
Shipbuilding production
In the last decades of the 20th century, the following directions of development of shipbuilding technology developed:
- Improvement of existing and development of new methods of building ships, including those based on the modular principle, in which it is possible to assemble ships from a limited number of unified primary elements-modules;
- Application of mathematical methods and computer technology in the technological preparation of production and process control;
- Mechanization and automation of production processes, including the use of industrial robots, robotic technological complexes, etc.;
- Development of fundamentally new technological processes using the action of lasers and plasma, more technologically advanced materials, high-performance equipment, including numerically controlled, high-precision measuring instruments;
- Saving material, energy, labor, financial and other resources in the creation of courts;
- Creation of safe working conditions and environmentally friendly shipbuilding processes.
Production and technological processes in shipbuilding
Under the production process is understood the totality of the actions of people and tools necessary for a given enterprise to manufacture or repair products. During the production process, raw materials, materials, semi-finished products are converted into products intended for consumption. The production process is formed in the presence of three elements: labor, that is, the purposeful activity of a person, the object of labor (the actions of the worker are directed at it) and the means of labor, with the help of which they influence the object of labor. The interaction of these elements, leading to the creation of new or improved products, forms production.
In shipbuilding, the production process is the directed actions of workers who, using the means of labor at their disposal (industrial buildings, structures, tools), manufacture ships, vessels, offshore technical installations or restore their ability to operate.
The components of the production process are the main and auxiliary processes. The main process includes the process directly related to the transformation of the object of labor into finished products. An auxiliary process facilitates the implementation of the main process without direct participation in it. The elements of both the main and auxiliary processes are labor, the object and means of labor. The difference is that the products of the main production process are used by third-party consumers, and the products of the auxiliary process serve it. In shipbuilding, all work related to the manufacture of products sold to the buyer is referred to as the main production process. Auxiliary processes are tool manufacturing, repair of production facilities, transport and loading services, etc.
The main production process is called the technological process, which is understood as a part of the production process that contains actions to change and (or) determine the state of the object of labor. Under the definition of the state of the object of labor understand the control of production (control actions carried out by the worker). In the course of the technological process, as a result of the actions of a person or machines, there is a change in the internal properties, shape, and appearance of the object of labor. For example, during cutting and bending, the dimensions and shape of parts are changed, and as a result of assembly, a conceived design is formed.
Technological processes are distinguished by purpose and versatility of application. The purpose determines the type of a specific technological process, as part of the ship construction process (technological processes of metal welding, painting structures).
Construction of the nuclear icebreaker "Siberia" According to the universality of application, technological processes are divided into single, group and standard. A single process is called a technological process for manufacturing a product of one name, size and design. Group processes include technological processes for manufacturing a group of products with different design, but common technological features. The technological process of manufacturing a group of products with common design and technological features is called typical.
Each technological process is divided into operations. An operation is a completed part of the technological process, performed at one workplace by the same performers. Examples of technological operations are cutting the workpiece into parts, installing and fixing the beams of the set on the panel; pipe bending on a pipe bending machine. The operation is the main unit in planning and accounting for production processes, in the development of technological processes, as well as in their study.
A technological operation, in turn, includes technological and auxiliary transitions. A technological transition is a part of an operation performed by the same tool with a constant mode of operation of a person or equipment. An auxiliary transition is understood as a part of the operation, consisting of actions that do not change the objects of labor, but are necessary to complete the technological transition. Examples of an auxiliary transition would be work clamping or tool change. In addition to transitions, the technological operation may include installations - parts of the operation performed with the workpiece being processed or the assembly unit being assembled unchanged.
The number of operations in the technological process depends on the constructive and quantitative variety of objects of labor (their repetition and unification), which characterizes the type of production. There are three types of production: single, serial and mass.
Single production characterizes a small volume of production of identical products, the re-production of which, as a rule, is not provided. In mass production, products are produced periodically and in repeated batches. Depending on the number of products in a batch or series, small-scale, medium-scale and large-scale production is distinguished. Mass production is characterized by a large volume of production of identical products, continuously manufactured for a long time.
Construction of the nuclear icebreaker Arktika The type of production is evaluated by the coefficient of consolidation of operations K 3.0 (serialization coefficient), which is understood as the number of operations performed on average at one workplace for a certain period of time (month, year). For mass production K 3.0 = 1. For large-scale production K 3.0< 10, для среднесерийного 10<К 3,0 <20, для мелкосерийного 20< К 3,0 <40 Для единичного производства К 3,0 не регламентируют.
Serial and mass production is characterized by an indicator of the release cycle (the cycle of the production process) τ , which is understood as the period of time between the manufacture of a unit of a product:
τ = T/N
- T- calendar period of time;
- N- the number of products produced during this time.
The value inverse to the release cycle, i.e., the number of products (products) produced per unit of time, is called the release rhythm. Indicators of tact and rhythm of output are used in planning and organizing production to calculate the number of workers, the number of necessary mechanisms and machines, shift work, and the number of required technological operations.
Serial and mass production of products is characterized by in-line production, which is determined by the location of technological equipment and tooling in the sequence of operations of the technological process.
In shipbuilding, there are no exact boundaries between types of production, since its products are a variety of vessels from small boats and fishing vessels to large-capacity sea vessels and warships. Single-piece production for the construction of single copies of ships and ships or serial production is more common. At the same time, the assignment of production to serial production depends on the size of the ships under construction. Mass production in shipbuilding is extremely rare.
Shipbuilding For the implementation of any technological process, one or another set of production tools is needed, which are called technological equipment (STO). These include technological equipment, tooling, fixtures and tools. Technological equipment - means of technological equipment, in which, to perform a certain part of the technological process, materials or workpieces are placed, as well as means of influencing them. Examples of technological equipment are bending presses, heat cutting machines, units for assembling and welding hull structures, pipe bending machines, boring machines, etc. Technological equipment includes service stations for the manufacture of hull structures (stands, beds, etc.), equipment for pipe bending machines, equipment for testing mechanisms, devices.
Devices mainly ensure the fixation or movement of objects of labor or tools during a technological operation. Devices are guides for moving along a given trajectory of semi-automatic machines for thermal cutting and welding machines, clamps and clamps for fixing parts, assemblies and sections of the ship's hull during their manufacture and assembly, devices used in the installation of shafting, mechanisms, pipelines.
The tool is designed to influence the object of labor in order to change its state. The range of tools used in shipbuilding is very wide. Here are marking, testing, assembly tools, tools for mechanical and thermal cutting of metal, tools for surface treatment.
The development of technological processes, the selection of existing or the creation of new means of technological equipment is carried out at the stage of technological preparation of production for the construction of ships.
About ship mechanics (video)
Welding is accompanied by welding deformations - there is a shortening of the welds in the longitudinal and transverse directions, warping of the sheets. To ensure the correct size and shape of the vessel, the docking of its individual parts, allowances are provided that are removed during docking. During the formation of the hull, a systematic check of the size and shape of the vessel is carried out (which is easier to do on horizontal construction sites). In addition, the quality of the welds is checked (by gammagraphy), the impermeability of the compartments (tests
water or compressed air).
shipbuilding technology
It should also be noted that, in addition to hull yards, shipbuilding plants include assembly (mechanical, electrical, pipe copper, etc.), outfitting (painting, furniture, hull-rigging), procurement (foundry, forging, woodworking), auxiliary (tool, repair) shops. Some of these workshops may be absent, and instead of them there may be separate specialized enterprises.
Usually on the slipway they strive to perform the maximum amount of work. For this purpose, the main engine, auxiliary mechanisms, ship devices and systems are installed, saturate with equipment and finish the ship's premises. The ship's hull is being painted. The launching weight of the ship is often limited by the possibilities of slipways, which may require the transfer of some work for completion.
shipbuilding technology
Launching a ship into the water is a very responsible operation. It is also given great symbolic significance. Usually, at factories, the launch of a ship, especially a large one, becomes a holiday - a bottle of champagne is broken on board, the ship is given a name (the veil is removed from the name); at the celebration, in addition to the workers of the plant, guests can be present. From that moment on, the ship finds itself in its native element - on the water.
shipbuilding technology
During a longitudinal descent, the vessel is first located on construction supports, then it is transferred to the launching device, which includes inclined paths covered with either a layer of packing (widely used paraffin-vaseline packing), or special plastic shields with a low coefficient of friction. For launching, the delay devices are removed, after which the vessel itself launches into the water. With a transverse descent, the movement occurs in the transverse plane. The tracks go into the water to a limited depth, so that during the descent, increased dynamic loads may occur.
shipbuilding technology
If the ship is being built in a dry construction dock, the dock is simply filled with water to launch. Note that in this case the ship floats up, however, the process is traditionally called the descent. During construction in a slipway (in a workshop), the vessel is mechanized (on hydraulic carts) rolled out to the shore and then rolled onto a special launch (transfer) floating dock. The dock with the ship is taken to a deep place and immersed (if the depth near the coast is sufficient, the dock sinks in place), as a result of which the ship is on the water. At modern shipyards, a controlled smooth launch is preferred.
shipbuilding technology
The construction of the vessel does not end with the descent. The vessel is launched in a certain, greater or lesser degree of readiness, depending on the capabilities of the launching device and the size of the vessel. Only small vessels after launching are completely ready to go to sea. The rest, after the descent, are diverted to the outbuilding embankment, where the completion process is underway. During completion, some mechanisms, devices, equipment can be installed, individual mechanisms can be tested. The progress of construction is monitored by representatives of the Register and the Central Design Bureau (TsKB) - the designer.
Most ships are built in series, consisting of several units - from 2 - 3 to hundreds, depending on the purpose and size. In serial construction, there are several methods of organizing labor that we do not consider.
shipbuilding technology
The built vessel passes acceptance tests, only after them it is handed over to the customer. We have already indicated that individual tests can be carried out in the course of outfitting work, which is formalized by special test certificates. The finished vessel is undergoing mooring tests at the shipyard wall. During these tests, the operation of the main engines, auxiliary mechanisms and systems, ship devices is checked. If the results are positive, the ship is sent for sea trials, the program of which can be more or less extensive, depending on whether the ship is a lead ship or a production ship, how unusual it is.
shipbuilding technology
The ship must be painted before testing to reduce water resistance, for which it is docked (if more than 2-4 weeks have passed since the launch). On sea trials, the speed of the vessel is determined under various modes of operation of the main engine, from the smallest to the full - for this purpose, it makes 3 runs in each mode in a specially equipped area of \u200b\u200bthe water area - a measured mile (measured line), during which the rotational speed and main engine power and ship speed. They check the operation of various mechanisms, ship devices, etc. The tests are carried out by the state commission, their conditions and results are reflected in a detailed act drawn up in a certain form. After testing, the mechanisms are revised, i.e. checking their status.
shipbuilding technology
The test program for simple serial vessels is relatively limited, while unusual or especially large vessels are tested for several months or even more than a year. The test program for large warships and new types of nuclear submarines is especially difficult. During the tests, shortcomings and errors of a different nature are often revealed: design, construction, technological, associated with the poor quality of work. These shortcomings are tried, if possible, to eliminate. In the most difficult cases, the ship is handed over with defects, trying to eliminate them on subsequent ships of the series, which may require serious research.
If the ships are built in a series, the cost of building the lead ship always turns out to be noticeably higher than the serial one, due to the cost of design, tooling, etc.
The shipbuilding company usually assumes warranty obligations. During the warranty period, which is usually one year, the factory fixes problems related to poor workmanship free of charge.
ship repair
Due to the complexity of ships, the presence of numerous mechanisms, instruments and other equipment on them, severe operating conditions, so-called failures occur from time to time (in the theory of reliability, a failure is understood as the output of certain equipment parameters beyond acceptable limits; these are not only accidents, breakage, but also excessive wear, etc.). To prevent or eliminate failures of the ship as a whole and its individual elements, there is a system of maintenance and repair of ships. Repair can be carried out according to the technical condition (if failures are detected) or planned preventive (in a certain volume and within predetermined terms, taking into account the standard service life of certain elements).
