Along with the “lucky” ships that have faithfully served people for decades, along with the less fortunate ships, whose life was limited to several trips, there is a small but truly unique group of floating vessels that have practically never taken a single “step” along the element for which they were intended. These, if I may say so, “ships,” as soon as their keel touched the water, they were immediately sent to the bottom, and from there either to a museum or to a landfill...
Flagship for an hour
This list is headed by the Swedish flagship Vasa, built under the personal leadership of King Gustav II Adolf, who may have been a good ruler, but he was definitely not a shipbuilder.
Gustav II acted like a king and did not waste time on trifles: the new flagship should be the most powerful, the fastest, the largest, and so on. undoubtedly the most beautiful ship on the entire Baltic Sea. The Dutch craftsmen working at the Stockholm shipyard looked at each other, sighed heavily, and began to satisfy the royal needs to the best of their ability.
On Sunday, August 10, 1628, the Vasa set off on its first voyage. The flagship turned out to be a sight for sore eyes, the Dutch shipbuilders did their best to please the fastidious ruler. The gilded heraldic figures and intricate carvings rivaled royal chambers in quantity and quality; 64 bronze cannons peeped menacingly from the ports, some of which were cut through by personal order of the king, in order to increase power; Snow-white sails covered the sky. The flagship "Vaza" left the port, moved a couple of miles away, turned around dashingly and, amid the jubilant shouts of the crowd, fired a mighty salute from all its guns...
When the smoke cleared, no sails were visible above the surface of the sea. Only the hull of the former pride of the Swedish fleet stuck out of the water as a gray spot, with glimpses of gold, and even that quickly sank to the seabed. Of the 450 officers and sailors of the Vasa, only a few people reached the shore...
Raised from the bottom in 1961, the Swedish flagship is now located on the island of Djurgården, in a museum specially created for it. Having carefully examined the surprisingly well-preserved hull, the researchers quickly understood why the “Vase” sank: masts, cannons, gilded wooden oak figures - everything was unusually heavy, and at the same time raised high above the water. There were no watertight compartments - they weren't even thought of at the time. And most importantly: the lower row of cannon ports, cut out by special order of King Gustav, was barely above the water level. As soon as the ship tilted slightly while making a turn, water rushed in through the open ports, and... the ship was doomed.
"Scottish" steamer
This happens when shipwrights know their job, but are forced to follow instructions from above. However, it happens that even experienced craftsmen make mistakes, as for example in the case of the steamship Daphne, which almost ruined the fairly famous Scottish shipyard - Alexander Stephen and Sons, located on the Clyde River.
This happened in 1883. The shipyard owner received an order from a large transport company to build a small steel steamship designed to transport livestock. The case was right, familiar, and the company “Alexander Stefan and Sons” began to work.
Since the ordered vessel in most respects was much simpler than the ships previously manufactured by the shipyard, the company's chief engineer did not begin to calculate everything anew. He took the diagrams of a larger steamship, the Briar, that had recently been launched from the stocks and, by analogy with it, designed all the ship’s equipment on the Daphne, in particular, writing in the specifications: “The same as on the Briar.” The builders, in turn, took this phrase literally, not realizing that the engineer did not mean dimensions, but only the type and order of placement of anchor, mooring and steering equipment on the ship. As a result of this double mistake, the relatively small steamer received equipment exactly the same in size as its larger brother, which was not slow to have an impact later...
A few months later the ship was ready. Whether the ship was large or small, its launching into the water always took place in a solemn atmosphere.
On Tuesday, July 3, 1883, the Daphne smoothly left the slipway into the waters of the Clyde. The whole process was worked out professionally, down to the smallest detail: the steamer, in front of the eyes of numerous port onlookers, smoothly and evenly entered the river and stood up, stopped in place by powerful anchors.
And then the incredible happened: “Daphne,” which seemed to be firmly resting on the calm waters of the Clyde, suddenly, for no apparent reason, tilted slightly to the left side, then straightened out, tilted even more and suddenly... turned upside down with its keel.
In those years, everyone who had even a slight connection with the construction of the ship had the right to be present on deck when it was launched. And therefore, at the time of the disaster, there were boilermakers, riveters and mechanics, painters and carpenters on board the Daphne, a total of 195 people.
All available boats and rafts rushed to the scene of the tragedy from the shore, but only 71 people were saved; the rest of the workers were dragged to the bottom by the treacherous steamer.
Three weeks later, Daphne was raised and docked for testing. It turned out that due to the larger and, accordingly, heavier equipment, the steamer received minimal initial stability. The light current of the Clyde was enough to stir the Daphne to create a list, which in turn caused loose equipment on deck to move towards the side. The tilt increased, water flowed into the hatches prepared for installing the boilers and... a tragedy occurred.
"Drunk Ballerina"
A similar incident occurred in 1905 at an Italian shipyard. A certain millionaire, anticipating profit from the ever-increasing flow of emigrants, ordered two powerful ships designed to transport 180 first-class passengers, 200 second-class passengers and 1,100 deck “landless” and unemployed people dreaming of trying their luck in South America.
By mid-September 1907, the first of the ships, named "Principessa Iolanta", was completed and stood on the shipyard slipway. Unlike the Daphne, steam boilers and machinery had already been installed on it, chimneys and masts had been installed, and the deck had been laid.
Everything happened exactly as at the Scottish shipyard: crowds of onlookers, a “christening” by hitting a bottle of champagne on the bow of the ship, launching and... a quick and therefore sudden capsize of the ship. The shipyard was quite small, and therefore the “Principessa” simply lay sideways on the bottom, burying the millionaire’s dreams of quick earnings.
Powerful cars, spacious decks and luxurious interiors of the liner turned out to be useless due to one small mistake: incorrect calculations of stability during design.
“Iolanta” was quickly raised and, without taking much time to sort it out, its hull was sold for scrap metal, and the unlucky shipyard was closed for six months - the government, for obvious reasons, prohibited the shipyard owners from building a similar steamship “Principessa Mafalda” until a complete revision of the project.
Later, the Principessa Mafalda nevertheless went out to the open sea and served on the line for nineteen years. However, despite the modifications, the hull of the ship shook so much at the slightest pitch that the team called their ship nothing more than a “drunken ballerina.”
And yet this liner turned out to be unlucky. On October 25, 1927, the propeller shaft broke and water entered the boiler room. The ensuing boiler explosion blew the ship to pieces, killing 314 people.
Shipbuilding enterprises have one or more construction sites, which can be inclined or horizontal. Inclined construction sites can be longitudinal or transverse. Horizontal construction sites intended for both the construction and launching of ships, dry or liquid construction docks. A large number of enterprises have horizontal construction sites separate from the ship launching facilities.
Rice. 1 Longitudinal inclined slipway
1 - bathoport;
2 - concrete slab - base;
a - H/L - slipway slope
The main operational characteristic of a construction site is the permissible linear load on its base - the basic supporting surface, which, depending on the length of the vessel, determines its maximum launching weight. The linear load ranges from 50 to 400 t/linear. m. Therefore, the foundations of construction sites must be strong and rigid, for which they are built on powerful pile foundations.
Longitudinal inclined construction site shown in Fig. 1, consists of surface and underwater parts. A longitudinal inclined construction site is called a slipway. The slope of the slipway is 1/16 for lengths up to 200 m and 1/20-1/24 for longer lengths. Slipways with a bathoport are common, allowing the underwater parts of the slipway and descent paths to be drained. The floating bateauport is brought to the threshold of the slipway, its ballast compartments are filled with water and the bottom is planted on the end of the slipway body. The water in the fenced bucket of the slipway is pumped out with pumps. At the end, along the contour of the walls and bottom of the slipway, wooden sealing beams are installed, to which the boat port is pressed by hydrostatic water pressure from the water area.
Currently, the construction of new inclined stocks has stopped, and the existing ones are gradually being taken out of service.
Due to the increase in the production of ships and the growth in their sizes, many shipbuilding companies have been actively constructing dry construction docks. Docks, as experience in their operation accumulated and ship building methods improved, became the main element of the entire construction system.
A diagram of a dry construction dock is shown in Fig. 2. It is a complex reinforced concrete hydraulic structure with a horizontal bottom.
Based on the tonnage of the vessel that can be built, dry construction docks are divided into docks for ships with a deadweight of up to 100 thousand tons, from 100 to 300 thousand tons and from 300 thousand tons to 1 million tons (superdocks). Dock lengths range from 300 m to 1000 m, widths from 60 m to 100 m, depths from 6 m to 17 m. Modern dry docks have in-dock seals that can be installed along the length of the dock, forming two or three construction chambers.
The possibility of forming chambers allows you to build several ships or their parts at the same time and launch them at different times. Docks come with one or two entrances, which are closed with a batoport (floating gate) or a folding gate rotating around the lower horizontal axis, or a sliding gate. The decline in orders for large vessels has meant that the development and construction of dry docks has slowed down.
Rice. 2 Scheme of construction dock 1 - portal crane;
2 - gantry crane
With the development of continuous forms of organizing the construction of ships, horizontal construction sites began to be used, which are a concrete platform along which rail tracks are laid. On rails on ship-carrying trolleys, part of the hull or the entire hull of the vessel is moved along the positions of the production line and to the launching facilities. The linear arrangement of positions on the construction production line is the most rational from an organizational and technological point of view, but then the length of the construction site can greatly increase. Therefore, horizontal construction sites with parallel positions appeared.
Construction sites tend to be located entirely or partially in buildings called boathouses.
Each construction site is equipped with lifting and transport equipment, a support or support-transport device, scaffolding and power supplies.
Lifting and transport equipment at construction sites includes cranes and other lifting equipment (elevators, booms).
The most common type of cranes for open construction sites are gantry cranes (Fig. 2). They have straight or articulated booms that can rotate 360° around a vertical axis. The crane moves along the constructed site along crane rails. The lifting capacity of portal cranes ranges from 20 to 150 tons.
Heavy-duty gantry cranes are used to service dry construction docks. Such a crane (Fig. 2) is a bridge on gantry supports that move on rails along the construction site. Cargo trolleys with 2-3 hooks move along the crane bridge. There are usually 2 trolleys and their total lifting force forms the crane’s lifting capacity, which can reach 1500 tons. The distance between the supports - the crane span - can be up to 200 m. Such cranes can serve not only construction sites, but also pre-dock areas located in front and on the sides construction site. They enlarge sections, blocks, and modules.
Rice. 3 Transborder scheme 1 - ship rails;
2 - transborder rails;
3 - steel rope;
4 - transborder;
5 - pulley;
6 - transborder pit;
7 - winch;
8 - ship trolley
In most cases, closed construction sites are equipped with overhead cranes, the lifting capacity of which reaches 100 tons or more. The crane is a bridge with rollers at the ends. It moves along rail tracks laid on overpasses located along the walls of the building.
Rail and road transport are used as vehicles for delivering goods to the construction site. To move sections (blocks) weighing up to 600 tons to the construction site, trackless pneumatic platforms towed by a tractor or self-propelled trailers of approximately the same carrying capacity are used. The loading platform is brought under the section (block) and hydraulic jacks are used to remove it (it) from the supports, transplanting it onto the platform.
After transportation, the section (block) is installed on the supports of the construction site, proceeding in the reverse order, or removed from the trailer by crane. The length of the trailer reaches 22-24 m with a width of up to 6 m. Sometimes, to move blocks or the vessel as a whole, a transborder is used, shown in Fig. 3, which is a welded truss moving on rollers on rails. The block (vessel) on ship-carrying trolleys rolls longitudinally onto the transborder and, together with it, makes a transverse movement. The transborder is moved by winches in the transborder pit - a buried area.
Rice. 4 Layout of elements of the support device 1 - keel blocks;
2 - cells;
3 - construction arrows;
4 - bases
The depth of the pit can be from 0.8 to 1.8 m. The length of the transborder can reach 100-150 m or more, with a load capacity of up to 2000 tons.
Hovercrafts have also been created. Such means require significantly less traction effort.
The supporting device is designed to maintain in a given position at the construction site both individual parts of the vessel and the entire vessel during its construction. The supporting device consists of keel blocks, cages, supports and stops, and on an inclined longitudinal slipway, in addition, of construction booms that prevent the vessel from moving. The layout of the elements of the support device is shown in Fig. 4.
Keel blocks are located in the centerline of the vessel under the floors and transverse bulkheads. The design of the keel blocks ensures their fixation and quick disassembly before launching the vessel, as well as adjustment of the position of the vessel, blocks, and bottom sections in height.
The simplest keel block, as follows from Fig. 5 is a set of welded metal pedestals stacked one on top of the other. The height of the keel block is adjusted by tapping a pair of oak wedges. Such keel blocks do not allow for easy disassembly when transferring the vessel from the support to the launching device; working with them requires heavy manual labor.
On inclined longitudinal stocks, quick-dismountable metal keel blocks are common. Shown in Fig. 5, b The keel block has two steel wedge prisms connected to each other by a rod made of a steel square. The traction is locked by a self-braking wedge. To release the keel block, the wedge is knocked out.
Hydraulic keel blocks are also used (Fig. 5, V), consisting of a lower part with a hydraulic jack, and an upper resettable part, consisting of metal pedestals and a wooden cushion. The hydraulic jack fixes the upper part of the keel block within the working stroke of the plunger. The presence of a unified oil supply system to all jacks allows for remote control of the height of the keel blocks and makes it possible to easily transfer the vessel from the support to the launching device by relieving the oil pressure.
Rice. 5 Types of keel blocks a - from metal cabinets;
b - quickly dismountable;
c - hydraulic;
1 - pine gasket;
2 - pine pillow;
3 - oak wedges;
4 - welded pile pedestals;
5 - traction;
7 - steel wedge;
8 - locking strip;
9 - hydraulic jack
The cages ensure a stable position of the vessel at the construction site and distribute concentrated loads, for example, from the main mechanisms, from water when testing compartments for tightness over a large area. A cage is often two keel blocks placed side by side. The cells are usually located under the transverse bulkheads.
As the hull sections are assembled and welded, stands and stops are installed at the construction site - stands under the bottom, stops along the sides. Pine logs with a diameter of 250-300 mm are used as supports and stops. Keel blocks and supports are installed vertically under the rigid connections of the bottom, and the stops rest against angles welded to the outer skin of the side. The lower ends of the stands and stops rest on wooden wedges or special shoes, consisting of two wedge prisms, locked with a metal wedge. To return the base, the wedge is knocked out.
The number of keel blocks is calculated from the diagram of the weight of the vessel. The stepped weight curve of the vessel is divided along its length into three sections, within which the load intensity is averaged and assumed constant. For each section the number of keel blocks:
n k = D pu /Q k
- Dpu - light weight of the vessel within the corresponding area;
The specific pressure on the keel block from the action of Q K should not exceed the permissible pressure on the cushion material, which is taken equal to half the pressure that destroys the cushion (for oak ≤3.2 MPa). With a pillow size of 25x100 cm, the design load will be 800 kN.
The number of cages must be at least three pairs for a ship with a launch weight of up to 5 thousand tons, four pairs for 5-10 thousand tons, and six pairs for a vessel weighing more than 10 thousand tons.
Number of bases:
n 0 = 0.4 D pu /Q p
The presented approach to designing a support device diagram is simple, but does not take into account the stress-strain state of the construction site structures, support elements and the ship’s hull. As a result, the launch weight of the vessel is underestimated, and the number of supporting elements is overestimated. A method has been developed for designing a support device diagram that makes it possible to accurately determine the load ratio in the triad of vessel - supports - slipway. The vessel is considered as a beam of variable cross-section resting on elastic-yielding supports - keel blocks, supports, cages and stops, forming a discrete support field under the hull of the vessel. The beam is loaded with a weight load distributed along the length of the vessel and horizontal forces arising from the shrinkage of the assembly welds and the effect of solar heat on the vessel's hull.
Rice. 6 Typical support diagrams for the width of the vessel 1 - keel block;
2 - stand;
3 - cell;
4 - stop
The reactions of the supports of the slipway support device (including the equivalent supports indicated below) are calculated by solving a system of equations for the angles of rotation of the sections of the ship's hull on the supports from the action of the specified loads - a system of modified five-moment equations. Equations of elastic subsidence of elements of the vessel - supports - slipway system are solved on a PC using the module of the "Slipway" software package. The complex allows, under a known load from the weight of a vessel or its part, to determine not only elastic, but also plastic deformations of the support pads. Thus, the necessary and sufficient number of supports at a given time is calculated or, in other words, the optimal composition of the support device.
Based on the calculation results, it is possible to establish the optimal number of standard support diagrams (TSS) shown in Fig. 1 for the width and length of the vessel. 6 and 7.
The support arrangement diagram is drawn by a plotter. A verification calculation is performed, which allows one to estimate the permissible launching weight of the vessel and the best arrangement of supports at any stage of vessel construction. Compared to traditional support placement schemes, their number becomes significantly less than that obtained using the calculation method.
Rice. 7 Arrangement of supports along the vessel a - the weight load of the vessel and the boundaries of the support sections;
1, 2,…., n, b - intervals of possible placement of supports;
- floras under which regulated combinations of supports are required
The support-transport device is designed to support the vessel under construction at the construction site in the required position, move the entire vessel or its parts (blocks) during in-line construction from one position to another and for launching. The main elements of the device are ship-carrying trolleys with a carrying capacity of 60 to 320 tons. In Fig. Figure 8 shows the components of the support module of the support-transport device.
The load-bearing element is a steel beam under the keel, which, during the construction of the vessel, rests on metal (or reinforced concrete) keel and side chairs, and when moving the vessel, on the transport (centering) supports of ship carts. Hydraulic jacks are built into their bodies, raising and lowering the vessel when transferring it from chairs to carts and vice versa. The jacks have systems for autonomous oil supply from their own manual oil pump and group centralized supply from a pumping station moving as part of a ship-carrying train on a separate bogie.
Non-self-propelled trains are pulled by cables with a winch traction force of 50 to 200 kN. The bogies are connected into a ship-carrying train by rods. The self-propelled train includes self-propelled bogies with electric or hydraulic drives.
Rice. 8 Support-transport device modules a - construction-support module (during the construction of a ship);
b - transport-support module (when moving the vessel);
1 - side chair;
2 - keel chair;
3 - steel beam;
4 - pine pillow;
5 - steel wedges;
6 - ship trolley;
7 - transport (centering) support
The speed of longitudinal movement of vessels is 2-4 m/min.
In order to maintain constant loads on the bogies when moving the vessel and eliminate the roll and trim of the vessel after moving, the bogies are combined into three groups:
- Bow left and right sides;
- Stern port side;
- Stern starboard.
The hydraulic jack cylinders in the group are connected by a common oil pipeline, forming communicating vessels, which ensures the same pressure in each cylinder of the group, i.e., the same loads on the transport support modules within the group, regardless of general and local unevenness of the rail tracks. If there is no group power system, then you have to manually maintain the required pressure in the jacks when moving the vessel, bleeding oil from the jacks in which the pressure increases, and pumping oil into the jacks in which the pressure drops. Such a system is imperfect and does not exclude emergency situations.
If there are a sufficient number of trolleys at the plant, the ship can be built on trolleys (without transfers), which simplifies its placement on supports and movement. While the vessel is being built, the hydraulic power supply system for the hydraulic jacks is turned off and the plungers are locked.
The required number of transport support modules should be determined taking into account the type of power system for the hydraulic jacks of the trolleys:
n t = TO N D S /Q t
- Q t - nominal load capacity of the transport support module, t;
- D S - launching weight of the vessel, t;
- TO N is the coefficient of uneven loading of transport supports.
For group power system TO H = 1.25, for autonomous TO H = 1.50.
Uniform loading of the transport support modules is ensured by placing them under the ship's hull with a variable pitch proportional to the intensity of the weight load along the length of the ship. A stepwise curve of the vessel's launch weight for 20 theoretical spacing is constructed, as shown in Fig. 9, integral curve:
D C = ∑ i = 1 20 Q i
On the horizontal axis, in addition to theoretical frames, points and numbers of structural frames are marked.
Design load on transport-support modules Q pt = D s / n t (hereinafter we will simply call construction-support and transport-support modules simply supports). By drawing lines parallel to the horizontal axis at distances equal to Q pt until they intersect with the integral weight curve and dropping perpendiculars from the intersection points to the horizontal axis, we obtain the basic arrangement of supports. The first line is drawn at a distance Q pт /2 from the abscissa axis. The distance between the last line and the extreme point of the curve should also be equal to Q pт /2.
Then the axes of the supports, located between the structural frames or under the assembly joints of the sections, are shifted under the nearest floors and transverse bulkheads, which will ensure coaxial loading of both the supports and the bottom connections, and will not interfere with the assembly of the hull. Each bottom section or block, when installed during the formation of the hull, must be supported in at least two sections. If this condition is violated, additional supports are introduced. Thus, the final location of the supports is obtained. Additional supports can be removed after the body is formed. With a group oil supply system for hydraulic jacks of ship-carrying bogies, reactions R 1 and R 2 transport supports are statically determinate, since the diameters of the jack cylinders and the oil pressure in them are the same. Reactions are calculated by solving the equilibrium equations of a ship on supports:
m T R 1 + (n T - m T) R 2 = D P
R 1 ∑ i = 1 m T Ɩ 1 i + R 2 ∑ j = n T — m T n T Ɩ 2 j = D n × x G
- n t is the number of transport supports in the aft group;
- Ɩ 1i , Ɩ 2i- axis distance i th and j th support from the lump perpendicular;
- x G is the distance of the center of gravity of the light ship from the stern perpendicular.
At n t supports exist n t - 1 options for their grouping. The optimal option will be in which the difference between the reactions of the stern and bow groups of supports is minimal (∆ R=min| R 1 — R 2 |). In all options, restrictions must be imposed on the magnitude of the reaction 0< R 1 < Q T и 0 < R 2 < Q T
Rice. 9 Scheme for determining the basic location of supports according to the integral curve of the vessel’s launching mass The reactions of construction and transport supports with the hydraulics turned off are statically indeterminable. To calculate them, you can use modified five-moment equations that take into account the influence of the compliance of the bottom floors of the hull, slipway slabs and their pile or soil foundations on the magnitude and distribution of support reactions.
With a straight keel line of the hull, leveled by hydraulic jacks using an autonomous power system, the reactions of the supports are also statically indeterminable and can be determined using the usual three-moment equations, since the keel line of the hull is straight and, therefore, the supports do not have different heights. When transferring a vessel from transport to construction supports without aligning the keel line after moving the vessel, the reaction of the construction supports is also statically indefinite, and we use five-moment equations with supports of different heights to determine them.
Each construction site is equipped with external scaffolding for access to the vessel under construction and access from the outside to any part of the hull where work needs to be performed.
The following are placed on the scaffolding:
- Compressed air pipelines;
- Pair;
- Gaza;
- Electrical cable network;
- Electric welding and other equipment intended for servicing workplaces.
Scaffolding installed in the compartments of the vessel is called internal.
At domestic shipbuilding plants, those shown in Fig. are widely used. 10 external tower-type scaffolding, consisting of towers located every 6-8 m, and working platforms laid on brackets between the towers in tiers every 2.5 m. The movement of people occurs along the marching ladders mounted in separate towers, or instead of ladders elevators and escalators are used.
Tower scaffolding requires:
- High consumption of metal and wood;
- Labor-intensive to manufacture;
- Installation;
- Operation, during dismantling before launching the vessel.
Improving scaffolding designs consists of replacing tower scaffolding with quick-dismountable scaffolding of a tubular design (Fig. 10, b), in the abandonment of solid scaffolding and the transition to the installation in the work area of portable platforms (shelves) of various designs, which are supplied by a crane and securely fastened to the hull of the vessel.
The design of internal scaffolding is determined mainly by the height of the compartments; in compartments up to 3.5 m high, trestles with wooden shields are placed, from 3 to 8 m - tubular scaffolding with panel flooring, more than 8 m - scaffolding on brackets, hung in tiers on welded hooks on bulkheads and sides. Panel flooring is laid on the brackets.
Instead of internal scaffolding, mechanized devices are used (Fig. 11), designed to deliver workers to the area of installation connections or to any other place inside the compartment. The device consists of a fixed post installed on the deck flooring and a platform that rotates along with a vertical column lowered into the space below deck.
Rice. 10 Outdoor scaffolding a - tower;
b - tubular and portable;
1 - tower;
2 - working platform;
3 - tiered ladder;
4 - tower with a marching ladder;
5 - racks of tubular scaffolding;
6 - shelves
A carriage moves along the column, to which a horizontal body-scopic boom is pivotally connected. A working platform is attached to the end of the boom, where workers are located and the necessary technological equipment is located. The carriage lifting drive is installed on the turntable platform. At the end of the telescopic boom, next to the working platform, a drive is installed to move it in a horizontal plane. The movement of the platform is controlled from a remote control installed on it. The device is fed into the compartment by a crane through standard holes in the deck, while the body of the scopic boom is located along the vertical column, and the working platform is folded.
Rice. 11 Device for internal access to the compartment 1 - stand;
2 - rotating platform;
3 - carriage lift drive;
4 - telescopic boom;
5 - remote control;
6 - working platform;
7 - power supply;
8 - stand;
9 - column;
10 - carriage
Each construction site is equipped with supply systems:
- Electricity - alternating current with a voltage of 380 V to power the electric motors of cranes and welding stations, a voltage of 220 V for constant lighting and power to the electric motors of fans that suck out harmful gases emitted during welding, cleaning, painting and other work, and a voltage of 36 V for portable lamps. Current is supplied from transformer substations to power switchboards in built areas. To power the cranes, current is supplied through flexible cables - trolleys, laid in trolley channels along the rail tracks of the crane;
- Compressed air with a pressure of 0.5-0.6 MPa for operating pneumatic tools and paint sprayers. Air is supplied through permanent main pipelines from the compressor station through moisture-oil separators-sumps to separation boxes, to which flexible portable hoses are connected to the tool;
- Oxygen and acetylene for gas cutting and gouging and for heating hull structures during straightening. Oxygen and acetylene are supplied to work sites through pipelines or delivered in cylinders;
- Carbon dioxide and argon for welding, supplied through pipelines or from cylinders;
- Steam for heating ship premises in the cold season;
- Water for hydraulic testing of hull structures for impermeability, fire protection purposes and other needs.
Cables and pipelines are laid along the entire construction site on both sides, and connection posts to highways are installed on scaffolding towers and platforms.
INVENTION
Union of Soviets
Socialist
State Committee
USSR about the affairs of inventions and discoveries (53) UDC 629.12. .002.28 (088.8) (72) Inventor
A. S. Blagovestny
Novocherkassk Order of the Red Banner of Labor Polytechnic Institute named after. Sergo Ordzhonikidze (71) Applicant (54) CONSTRUCTION OF SULOV DESCENT
FROM THE PILE
The invention relates to shipbuilding, namely, to devices for launching ships from the slipway.
A device for launching ships from inclined slipways is known, consisting of a set of launching skids with a wooden lining or casing made of aluminum-magnesium alloy on the bottom, and slipways with oak flooring or covered with shields made of anti-friction plastic PM (1).
The disadvantage of the known device is the need to transfer the vessel before launching from the support to the launching device, the complexity of applying a layer of nozzle or lubricant to the slipway tracks before launching and the difficulty of removing it after launching the vessel; the impossibility of controlling the magnitude of the friction force and the speed of the vessel during descent.
The closest known solution is a device for launching ships from a slipway, containing a set of launching skids and slipway tracks, with water lines with valves connected to the skids, and seals (2) installed between the tracks.
The disadvantage of this device is its low reliability when lowering ships from the slipway.
The purpose of the invention is to improve the performance of the trigger device.
This goal is achieved by the fact that the launching skids are equipped with a waterproof pontoon, to the lower part of which is attached a support device consisting of a body with guides, with a moving frame equipped with a lining made of antifriction material, and between the body and the frame there is a mechanical lift height limiter and elastic elements, and on the outside of the body there are rulers installed that interact with the valves of the water lines, connected to the descent tracks, on the valves of which rollers are installed, while the body and the frames are equipped on the outside with a covering flexible sealing element.
Claim
TO;),:")! oh, II!)3 g!II e, ICìCORDOVA weave
N y f1)g.)yukyzy and general IIH J usgo
On tracks 1 of the slipway, launching skids 2 are installed, consisting of waterproof pontoons, to the lower part of which support devices 3 are attached. Excess pressure is supplied to the internal cavities of the support devices (I, .)H through pipeline 4 through valves 5.
The housing 9 is equipped with guides along which a frame 11 moves, equipped with a lining 12 made of anti-friction, for example, self-lubricating, material.
A mechanical lift height limiter is installed between body 9 and frame 11! 3 and elastic elements 14. From the outside, the body 9 and the frame 11 are covered by a flexible sealing element 15, made, for example, of rubberized cord fabric. The internal cavities of the housings 9 and frames 11 form hydrostatic supports. The distance between the pipelines located in the slipways and supplying water to the hydrostatic supports must be less than the length of the cavity of the hydrostatic support.
Device operation. l under the action of the weight of the vessel, assembled IIB launching device, the slides 2 of the descent IQTcII on the frames 1, in this case, the rulers 7 open the valves 5 for supplying water to the hydrostatic olloors, and the elements are compressed!4. Before lowering the vessel, water is supplied under pressure into the pipeline 4. As a result, the body 9 of each support device rises above the frame!1 and the weight of the vessel is taken up by the hydrostatic pressure of the fluid. 14 elements press the linings
12 ll frames to the slipway tracks with some constant force required to reduce water leakage. Part of the water flowing out from under the linings 12 acts as a technological lubricant and at the same time washes away contaminants from the tracks of the slipway. To obtain the highest speed of the vessel during descent, hydrostatic pressure
40 howl weight suna, in this
H by the forces of boundary friction of the linings along the tracks of the slipway. In this way, the speed of the vessel's movement along the slipway tracks during descent can be adjusted. As soon as the pipeline through which water is supplied to the hydrostatic support is outside the support cavity, the influence of the ruler 7 on the roller 6 for controlling the water supply valve stops, and it closes this pipeline. This prevents pressure drop in the cavities of adjacent hydrostatic bearings.
The launching of ships using the proposed device can also be carried out by supplying air through pipeline 4 instead of water under appropriate pressure. The device can also be used for lifting ships onto a slipway. The supporting devices of the proposed design, when air is supplied to them, can be used in high-speed land transport on an air cushion and in container pipeline pneumatic transport.
The device reduces the labor intensity of the process of manufacturing and launching a vessel by assembling the vessel directly on the launching device and eliminating the need to use a nozzle, an adhesive or any other lubricant, as well as creating opportunities to control the friction force and speed of movement ship during descent.
1. A device for launching ships from a slipway, containing a set of launching skids and slipway tracks, where water lines with valves are connected to the skids, and seals are installed between the skids and tracks, characterized in that, in order to improve the performance of the launching device, the launching skids are equipped a waterproof pontoon, to the bottom of which is attached a support device consisting of a body with a guide
I7 uz. 5 (left by G. Roi!сll) in
Editor K. Borodin Tereya O., Lugovaya Corrector 1=.. 1i ii)(kaya
Order 42(16 Circulation 513 Subscribed!
1NIIPI of the State Committee of the USSR on matters of invention and discovery! 1 3035, Moscow, Zh-35, Raugiskaya embankment, 4/5
Branch of PPP "Patent", Uzhgorod, st. Designed, 4-piece made of anti-friction material, with a mechanical lift height limiter and elastic elements installed between the body and the frame, and installed outside the body. Interaction with the valves of the water lines connected to the descent tracks, on which rollers are installed, while the body and frames are equipped with a covering flexible sealing element on the outside.
This method of descent is the most labor-intensive and requires the installation of a complex descender device.
The main elements of the trigger device (Fig. 13.41) are trigger skids, tie strings, spacer bars, under-peritoneals, wedges, crushing gaskets, spears, lashings, delay devices, braking devices, trigger keel blocks.
Rice. 13.41. Scheme of the tanker launching device.
1 - trigger skid; 2 - spacer beam; 3 - abdomen; 4 - tie string; 5 - lashings; 6 - stern hooves; 7 - nasal hoof; 8 - nasal retainer; 9 - launch anchor.
Rice. 13.42. Wooden runner.
The runners come in wood and metal. Wooden runners (Fig. 13.42) are made from pine beams with a cross-section of 200 X 200-300 X 300 mm, laid in one to three rows in the longitudinal direction. In the vertical and horizontal directions, the runner bars are connected by through tie bolts. The ends of the runners have smooth curves at the bottom to prevent the packing from being torn off from the slipways during the process of lowering the vessel. The runners are connected to each other using strips with retractable stoppers. The length of the runners is 5-10 m, depending on the length of the vessel and its launching mass.
The purpose of the tie strings is to keep the skids from moving apart as the vessel moves along the launch tracks. These strings connect the runners of the opposite sides. Strings are made from steel strips or squares. To prevent spontaneous pulling out of the strings, their ends, made in the form of pins, are passed through the runners and secured from the outside with nuts.
Spacer bars serve to prevent the runners of the left and right sides from approaching each other during the descent process. Spacer bars are usually made from pine beams of round or square cross-section. Sometimes they are made of steel pipes, then they also serve as tension strings.
The bellies are designed to absorb and transmit the ship's load to the launching skids. Typically the underbelly consists of a single row of horizontally laid pine beams connected by tie bolts. The underbelly has the same width as the runner; the length of the underbelly is 10-15% less than the length of the runner. Between the abdomen and the hull of the vessel, a cushion is assembled, which is fitted along the contours of the hull. Pine beams are used for the pillow.
The wedges are located between the underbelly and the runner. They are designed to press the abdomen against the body. Wedges are made from oak or pine. The embedded (lower) wedge is usually made of pine, and the running (upper) wedge is made of oak.
The width of the wedges is 180-250 mm. The length of the embedded wedge is equal to the width of the runner or slightly greater than it; the length of the running wedge is 300-400 mm greater than the width of the runner. The sharpening angle of the wedges is assumed to be within 3-4°.
Collapsible gaskets are an elastic-plastic element introduced into the trigger device to redistribute local pressures exceeding permissible ones over large areas. Crinkle pads are usually made from spruce, basswood or fir. The gaskets are installed in the plane of the wedges (above or below them).
Spears are supports for the ends of the vessel and are therefore divided into bow and stern. The design of the spears can be different. They are often made from wooden beams or made of steel (from angles or channel beams). On the upper plane of the hoof (Fig. 13.43) a shoe is installed, made according to a template corresponding to the contours of the body. The shoe serves as a support for the towel, which is lined with pine boards. The lower end of the hoofs is placed on the underbelly or on the runner. In the latter case, the lower supporting plane of the spears must have a backing into which the wedges rest; ties are used to keep them from moving apart. In order to ensure the stability of the spears, one or more metal longitudinal beams-shafts are installed on their outer and inner sides.
Rice. 13.43. Hoof design.
1 - runner; 2 - hooves; 3 - shoe; 4 - towel; 5 - screed.
When the stern rises during descent, the vessel rests on the slipway only with its bow. In this case, a large pressure of the vessel on the slipway (called buck pressure) arises. To reduce the bucking pressure, it is distributed over a large length of the descent tracks, using rotating nose caps, one of the designs of which is shown in Fig. 13.44.
Rice. 13.44. Nose swivel hoof.
1 - lower part; 2 - upper part; 3 - hinge.
The lashings are designed to connect the structures of the launching device to the ship's hull in order to prevent displacement of the launching device relative to the hull during lowering and to hold the launching device on the ship's hull after its lowering. Lashings are made from steel strips, profiles or metal cables.
Detaining devices serve to hold the vessel on the slipway after it has been transferred from the construction supports to the launching device until the moment of launching. Arrows, triggers, and bow stoppers are used as delaying devices.
Bow arresters are installed in the bow of the vessel. One end is attached to the stem of the ship or to the bow end
the skid, and the other to the slipway. Before descent, the nasal retainer is cut.
A braking device (temporary anchors, sometimes dredges, brake shields, etc.) is used to brake the vessel after leaving the slipway.
Launching keel blocks are designed to transfer the vessel onto the launching device. These keel blocks should give off easily. There are several designs of such keel blocks, some of which were discussed at the beginning of this chapter.
Preparation of the slipway and launching device includes a large range of works: inspection of the slipway, cleaning of the launching tracks from old grease and dirt, inspection of the launching tracks, checking their sliding plane, selection of parts of the launching device, their inspection, repair, etc.
One of the first operations preceding the direct installation of the launching device on the slipway is the setting of the launching tracks and runners. Nasalki are divided into two main groups: mineral and combined. Mineral lubricants consist of various petroleum products. The most common packings in this group are paraffin-petrolatum and paraffin-vaseline. Combined packings consist of petroleum products, fats and products of the forest chemical industry. This group includes soap nozzle.
In recent years, some factories have successfully replaced the nozzle with special plastic with a low coefficient of friction.
Installation of the trigger device begins with installing the slugs and tightening the trigger skids.
The slugs protect the packing layer from being squeezed out when installing the runners, as well as when the trigger remains on the packing for a long time. Slugs are steel strips 80-120 mm wide and slightly longer than the width of the runner. They are installed in a strictly defined quantity.
The runners can be pulled in from the bow or stern. Often the runner is pulled together with the underbelly. The skids are usually tightened by slipway cranes using a rosin block system. After tightening the runners, install the underbelly (if it was not installed earlier) and the hoofs; then tie strings, spacer bars, lashings and other parts of the trigger device.
Launching the vessel is as follows: the slugs are pulled out from under the runners, then the construction keel blocks are removed, leaving only the launching keel blocks. Then the stops and supports are knocked out. The wedges of the trigger device are tapped and the trigger keel blocks are removed. Detainees give up last. After this, the ship begins to move along the slipway and goes into the water.
Launching the vessel- a significant event in the life of the ship and the workdays of shipbuilders. But why exactly is the launch significant? After all, this is nothing more than an intermediate stage in the construction of the ship.
After launching, the construction of the ship sometimes continues for years. This is most likely due to two circumstances. The first of them is that at the moment of launching the ship passes from one environment to another, ending up in its native element. The second circumstance: the launching of the vessel is the only moment in the process of its construction that has a clear time reference. Indeed, no one knows when the construction of the ship begins, but the end of construction is clearly defined. This moment is the signing of the act of acceptance of the vessel into operation and the hoisting of the customer’s flag on it. However, this is only the documentary side of the matter. But in fact, the ship at this moment may not yet be “built”. Obvious deficiencies and hidden defects are not so rare in shipbuilding practice, and they are eliminated (essentially the completion of the vessel) after the vessel is put into operation.
Launching the vessel The year, day and hour clearly correspond. That is why the descent was solemnly celebrated in shipbuilding in all centuries. At first, the celebrations had the character of a religious ceremony. Then everything religious disappeared, but the peculiar “rite of baptism” remained. And today, during the descent, the “godmother”, as a rule, is a woman, in the presence of a large number of witnesses, who breaks a traditional bottle of champagne against the side of the ship.
For launching ships Currently, various methods are used and a variety of structures are used.
METHODS OF LAUNCHING VESSELS
Launching ships The slipway period of ship construction ends and the outfitting period begins. Modern technology ensures maximum readiness of the vessel before launching. The moment is selected depending on the technology adopted, the production conditions of the construction plant and the time of year. Before launching, mandatory work must be completed: assembly and welding, ensuring the tightness and strength of the vessel; painting the underwater part of the hull and applying load lines; installation and testing of outboard fittings; installation of the stern tube; installation of rudders, propeller shafts and propellers, rotary attachments; installation of the necessary parts of the mooring device and rescue equipment; securing mechanisms and cargo supplied to the vessel.
There are several methods of launching ships: free - on an inclined plane under the influence of gravity; by ascent - when the water level in the launching structures rises; forced - mechanized.
launching a ship by gravity
Descent under the influence of gravity (longitudinal and transverse) is the most difficult. The period of the actual descent is very short, and the preparatory work takes a lot of time.
longitudinal descent
Longitudinal launching of ships carried out from longitudinal inclined stocks from 100 to 350 m long, located perpendicular to the coastline or at a certain angle to it. The slipway is a complex engineering structure that has a reinforced concrete base to accommodate descent paths. It consists of surface and underwater parts.
transverse descent
Transverse launching is usually used for launching small and medium-tonnage vessels in shipyards located on rivers. For the transverse launching of a vessel, structures are used that consist of a horizontal slipway (pre-launching position) and inclined launching paths directed perpendicular to the slipway axis. The slope of the descent tracks is much greater than on longitudinal slipways. Descent paths are placed on the ground or on a reinforced concrete base and buried in the water by 1.5 m or not buried at all.
launching ships by surfacing
Ship launching by surfacing carried out in dry docks, the chambers of which are filled with water coming from the water area, in loading docks and dock chambers filled with water using pumping stations. The docks are filled with water to a level at which there is sufficient clearance under the bottom of the surfaced vessel to remove it from the keel blocks.
forced mechanized descent
Forced mechanized descent carried out using the following structures: transverse and longitudinal slips, vertical ship lifts, cranes and floating docks.
transverse free descent
The basis transverse descent The principle of free movement of a vessel along an inclined plane under the influence of its own weight is established. The design of the descent devices with this method is much simpler and the descent paths are shorter than with longitudinal descents. The reduction in the length of the tracks is facilitated by a large slope and the use of special types of transverse descent: jump descent, throw descent and descent using a pontoon.
Depending on the location of the slipways, transverse descent can be carried out according to several schemes.
Descent directly from the construction site (slipway) occurs with the help of launching devices, which consist of several rotary beams (balance tables) and are also the supporting surface of the construction slipway.
The device shown above consists of a pivot beam supported at its extended end towards the launch tracks by a hydraulic jack, a pivot support and a trigger clamp. Under the influence of the overturning moment from the weight of the vessel, the beam tilts until the launching slide aligns with the launching tracks. Then, with the help of pneumatic cylinders, the delay triggers are released, and the ship is lowered into the water along the greasy paths.
Descent with the vessel moving onto the launching shoals. To launch, the vessel is moved on ship-carrying trolleys to the pre-launch position, where jambs and launching skids secured with special arresters are placed under it. The vessel is transferred from the carts onto the launching skids and lowered using winches to the launching position, from where a free descent is made along the greasy paths. Since the launching tracks during transverse descent have a slope, the weight of the vessel and the launching device creates the driving force of the vessel and the force of normal pressure on the slipway. An increase in the support area of the runners entails an increase in the weight of the descender and, consequently, its cost. A feature of the transverse free descent is that from the moment the vessel begins to move along the launch paths, the descent process becomes practically uncontrollable. From the moment the body enters the water, a resistance force appears in the direction of movement, and a supporting force appears in the vertical direction. The ship not only moves forward, but begins to rotate around a longitudinal axis passing through the center of gravity of its cross section. When the weight and supporting forces are equal, the ship floats.
The transverse launching of a vessel includes many operations: preparation of the slipway and launching device; drawing up a descent schedule and distribution of workers participating in the descent; inspection by divers of the underwater part of the descent paths; drying tracks and runners, applying coating; moving to the launching position of the vessel using a special winch; winding and securing runners under the vessel; cable wiring devices to prevent skidding of ends; lifting the vessel with hydraulic jacks and final installation of the runners along with the keel blocks installed on them in their standard places; securing the runners to the arresters and installing special snacks; transferring the vessel to the launching device using hydraulic jacks and rolling out transport carts from under the vessel.
After the vessel is launched, a special team that arrives with a tugboat carries out a thorough inspection of the compartments of the surfaced vessel and eliminates any defects noticed. The vessel is transferred to the pier for completion and testing.
Perhaps in the future there will be new ways to launch ships. For example, ships under construction will be launched in parts, with subsequent joining of their sections afloat. The docking of ships afloat has been carried out for a long time. To weld the mating parts of the vessel, caissons or various patented sealing devices are used. In addition to welding, to connect parts, it is possible to use mechanical locking devices, similar to those used to couple ocean barge-tug trains. In the future, obviously, methods and means of docking ships afloat can be improved. There is very wide scope for our descendants for inventive and engineering activities. Therefore, docking afloat will become a routine technological operation in the 22nd century and will firmly become part of the practice of large-tonnage shipbuilding shipyards. This will make it possible to limit the load capacity and dimensions of launching structures to structurally and economically reasonable limits. Such structures will make it possible to launch large ships and components of large-capacity vessels.
