When carrying out a ship-lifting operation, the holes are sealed temporarily, only so that the ship can be brought to a repair point, where it is given the appropriate repairs.
Sealing with external adhesive
In river practice, soft patches made of canvas in one or two layers are usually used. The patches are made in square sizes of 1.5 X 1.5 m, 4.5 X 4.5 m and 6 X 6 m. Along the edges, the canvas is sheathed around a lyctross, from which loops with thimbles are made at the corners of the patch. The ends of a hemp cable with a circumference of about 75 mm are attached to the thimbles, using which the patch is brought into place and secured to the vessel.Laying tow between two layers of canvas in a plaster cannot be considered rational, since this causes rapid rotting of the plaster and its failure.
To close a hole in the ship's hull, the plaster is applied from the outside of the hull and, if possible, pressed against it by the foundling ends. If you start pumping water from the damaged compartment, the water pressure will press the patch against the hole and stop the flow of water into it.
The patch is applied in the following order. On both sides of the damaged area of the hull, under the hull ends are inserted, through which they are pulled under the vessel, tied to two adjacent corners plaster the ends of the cables. Selecting these ends from the opposite side, drag the patch so that its middle is opposite the hole. Then the ends are pulled out tightly and secured to the sides of the ship.
The disadvantage of these soft patches is that if the hole has sharp edges protruding outward, the patch can be easily torn. IN equally a soft patch cannot stop the flow of water through a hole if the dimensions of the hole are very large, since in this case the patch will be squeezed inside the vessel by water pressure.
In such cases, instead of a soft plaster, so-called Swedish plaster is used, made from two or three layers of boards 50-75 mm thick, between which canvas and resinous tow are laid. In the places where the Swedish plaster adheres to the body, wooden strips are sewn, upholstered soft pillows for a tighter fit. To neutralize positive buoyancy, metal weights (usually pieces of old chains) are suspended from the patch.
To cover particularly large holes, the wooden plaster is shaped into a box. This patch is called a caisson. The caisson is fastened with the keel ends. To maintain strength, spacer bars are placed inside the box.
Internal patches
The patch used to repair damage to the hull from inside the ship is made as follows. A layer of resinous tow is applied to a piece of canvas or an ordinary bag, approximately three to four times the area of the hole; The tow on top is coated by hand with an even layer of grease, on top of which another layer of tow is placed, and again canvas is placed on top. This patch is easily tied lengthwise and crosswise with thin twine or heel. The total thickness of the plaster is about 5-8 cm. The plaster is placed on the damaged area of the body, and cuttings of boards 50-75 mm thick are placed on top. It is better to hammer these scraps tightly between any parts of the hull frame, for example, between frames, floors or stringers. Due to the fact that water pressure tends to push the patch away from the hole, logs or thick boards are placed on top of the boards, which are tightly pushed into beams, carlings or other reliable connections of the body.If the leak through the hole is not so strong that it could prevent the installation of the internal plaster, then the seal using the described method will quite reliably withstand a fairly long passage of the ship.
Sealing with an external tampon
Tampons are used to temporarily plug small holes and especially in cases where inserting patches is impossible. A tampon is made in the same way as an internal patch and is applied to the hole by a diver from outside the vessel. When inserting a tampon, the water must be pumped out at the same time, since only under this condition will the tampon be pulled towards the hole, partially penetrate the hull and stop the access of water to the vessel.If the diver cannot approach the hole, then the tampon is tied to a fairly long stick with a string about 30-40 cm long, counting from the end of the stick to the tampon. With this stick, the diver moves the swab under the hull in the area of the hole until a stream of water pulls it up and plugs the hole. In this case, of course, the water from the vessel must be pumped out. Sometimes it is possible to insert a tampon by moving it on a long stick, from a boat, or even from the emergency vessel itself,
Having achieved the cessation of water access into the vessel, they perform a complete pumping and seal the hole from the inside, after which the tampons themselves fall off.
Wood sealing
Small cracks and holes in the outer hull, loose joints and grooves in the skin can be temporarily sealed by a diver using wooden wedges driven from the outside of the vessel. The wedges are made from dry wood in order to increase the sealing density after swelling in water.Wooden wedges are a temporary measure and must be replaced immediately after the vessel arrives at the repair point.
It is sometimes possible to stop minor leaks through small cracks along diverged grooves and joints of the outer plating by allowing water to flow from the outside of the vessel against the leak site. sawdust, bran or rubbish from ant heaps: small parts of wood or bran become clogged in crevices, swell and the flow stops.
It goes without saying that similar method stopping the leak is temporary, suitable only for the duration of the ship’s short passage to the repair point.
Sealing Yemeni
Sealing with cement is reliable not only when dry! hold, but also under water. In the latter case, for reliable sealing, the work of laying cement must be carried out with special care. When repairing damage, fast-setting types of cement should be used to avoid unwanted erosion and leaching. Before laying cement, the damaged area must be thoroughly cleaned of paint and rust until it shines and washed with green soap. It is not recommended to touch the iron prepared in this way with your hands, so as not to apply a layer of fatty substances and cause cement to lag. To prevent the cement from spreading, it is necessary to arrange formwork from boards around the entire damage.It is much more difficult to cement if water continues to flow through the damage, which easily makes a channel in the freshly applied layer of cement. In such cases, it is necessary to first drain this water through a piece of pipe or a specially knocked down wooden gutter. Having installed such a drain, they cement the entire area around it. After the cement has set, the created water flow is tightly (clogged with a plug,
In case of major damage that has caused weakening of the casing, it is necessary to lay a frame of iron rods, wire or pieces of iron inside the cement, which increases the strength of the seal.
To seal holes, cement is taken in a mixture with sand, in a ratio of 1: 1 to 1: 4, depending on the required strength and speed of its setting. The less sand, the faster the setting usually is.
To reduce the leaching of concrete by water during its setting and to speed up this process, the concrete should be mixed in warm water, to which is added liquid glass. After placing the concrete in the formwork, it must be compacted well, which ensures greater water resistance when hardening.
You should not seal holes with a solution of pure cement, as is sometimes observed in practice.
When choosing the composition of concrete, you can use the following table:
Sealing with clay
Clay sealing is not durable and is used only as a temporary measure to stop the leak until the damage is more permanently repaired. This method is completely inapplicable if any significant amount of water continues to flow into the hole.When plugged from the outside with a plaster; When water enters, work is performed as follows. Around the damage, a formwork that is as dense as possible is made from boards, and individual boards should be fitted as accurately as possible to the shape of those parts of the body to which they adjoin. Clay is placed into the formwork in layers and compacted tightly. The thicker the clay layer, the more reliable the seal. It is useful to lay some layers of clay mixed with thin shavings, straw or sawdust, which delay the washing out of the clay by seeping water. In addition, after removing the outer patch, it is good to bring sawdust to the site of damage, which is carried into the hole by streams of water, fills individual cracks in the seal, swells and thereby stops or greatly reduces the flow of water into the vessel.
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Repairing damage to the hull using concrete has significant advantages over other methods, because It is distinguished by reliability, durability and tightness. Concreting makes it possible to repair damage to the ship's hull that would simply be impossible to achieve by other means. For example, practice has shown that in most cases, only concreting can restore the tightness of flooded compartments of a ship sitting on rocks or rocky soils. Concreting also makes it possible to repair damage in hard-to-reach places of the ship, for example, under the foundations of machinery and mechanisms, in the fore and after peaks and on the cheekbones.
Concreting the water-flow areas of the building also has the advantage that this method can achieve absolute impermeability of the damaged areas, whereas other temporary seals may not provide this. With the help of concrete, you can repair any damage - from minor damage to rivet seams to large breaks in the bottom or sides.
Many years of experience and observations have shown that properly executed baton sealing lasts a long time, is durable and often eliminates the need for immediate docking of ships.
To prepare concrete, sand, gravel, and broken brick or in as a last resort slag.
The recipe and methods for preparing concrete mixtures are given in the manuals for maritime practice. Mechanical properties concrete based different varieties cement in the table.
Note. The numerator shows the strength when hardening in water, the denominator shows the strength when hardening in air.
There are 2 types of concreting: air and underwater.
When air concreting, the damage is laid metal sheet, around which formwork is made and filled with concrete.
When underwater concreting, the water flow is first diverted from the hole so that it does not erode concrete mixture before the mixture “sets”. To drain water, a drainage pipe is installed, which can simply be plugged after the concrete has hardened.
Concreting damage to the bottom, 2nd bottom, or deck is no different from concreting damage to the side.
Any concreting of any damage to the hull is a temporary measure, and when the vessel is docked or upon its arrival at the port, damaged connections are replaced or holes are welded. To ensure greater safety of navigation, sometimes at the request of the Register concrete sealing they are scalded on the ship's hull, i.e. enclosed to be welded to the body steel box. In this case, if possible, the crack itself or the broken seam in the ship’s hull is welded from the outside or from the inside.
The sheets forming the box wall around the concrete enclosure, or cement box, are usually welded directly to the shell or frame of the vessel. Then all the free space of the cement box is filled with new mortar and sealed with overlay sheets on top.
If concreting is carried out in the port, then the concrete seal must be welded. A steel box with a tube welded into it is attached to the ship’s hull, filled with coarse aggregate and concrete is laid on top with a steel sheet.
Various options concreting damage after preliminary sealing from the inside of the vessel in any way is shown below.
Plasters used as emergency equipment are soft, wooden, metal and pneumatic.
Soft patches are applied to temporarily seal the hole in order to drain the flooded compartment and then reliably restore the waterproofness of the hull. The most durable soft plaster is the chainmail plaster. It is elastic, fits well to the figured surface of the ship's hull and at the same time has a certain rigidity, which is created by chain mail in the form of intertwined rings made of flexible galvanized steel cable with a diameter of 9 mm.
The lightweight plaster, measuring 3x3 m, consists of two layers of canvas with a felt pad between them. To give rigidity to the plaster, 25 mm steel pipes or a steel cable with a diameter of 20 mm are attached on its outer side parallel to the upper edge at half-meter intervals.
The stuffed plaster (2x2 m) is made of two-layer canvas and a stuffed mat stitched on the inside with a dense, thick pile on the outside.
The mattress patch can be made by the crew on board. For this purpose a canvas bag required sizes stuffed with resinous tow to a thickness of about 200 mm. From the outside, narrow boards 50–75 mm thick (with gaps between them) are attached to the mattress thus obtained, and a steel cable is nailed to them with construction staples for winding.
A wooden rigid plaster is usually made on site on the ship after a hole has been received in the hull. It is most appropriate to use it to close holes located near or above the waterline, as well as in cases where the hole can be exposed by heeling or trimming the vessel.
Metal patches used to seal small holes are shown in Fig. 6
Pneumatic plasters (tubular, spherical, soft box-shaped, semi-rigid and rigid) are designed for sealing small holes from the outside at a depth of up to 10 m.
3.1. Installation of a metal patch with a clamping bolt pb1.
Holes with a diameter of 35 – 100 mm with a height of torn edges up to 15 mm can be repaired metal patch with a clamping bolt PB-1. The patch can be installed by one person and does not require additional fastening after installation. On the ship, the PB-1 patch (Fig. 5) is stored in constant readiness for use, assembled, the nut with handles should be in the upper threaded part of the clamping bolt.
To install a patch on a hole you need:
install the rotary bracket, overcoming the force of the spiral spring, parallel to the axis of the clamping bolt;
Insert a clamping bolt with a rotating bracket into the hole so that, when it goes beyond the casing, it rotates under the action of a spring perpendicular to the axis of the clamping bolt;
holding the patch by the bolt, rotate the nut using the handles and press the rubber seal with the pressure disk against the casing until water leaks from the hole are eliminated.
The non-working surfaces of the patch are painted with red lead, the working surfaces (pressure bolt, spring, nut thread) are lubricated with grease, the rubber seal is covered with chalk.
Leaks on a yacht can be caused by a variety of faults: holes, loose seams, leaking seals, etc. Regardless of the cause, any leak poses a serious danger to the ship and its crew. In this regard, if seawater is detected entering the yacht, all measures should be immediately taken to eliminate this malfunction.
Cause of leak
The arsenal of modern sailors includes a large number of ways and means of eliminating sea leaks. The use of one or another housing sealing technology depends on the cause of the leak. Before you begin to eliminate the accident, you should establish the cause of the leak and assess its size. As a rule, there are two main reasons, they are closely related to each other:
- End-to-end mechanical damage hull due to impact with rocks, a pier, another ship, as a result of grounding, exposure to storm waves. Such damage includes: holes and cracks in the body, loose seams.
- Depressurization of the housing due to technical malfunctions and physical wear of components and parts. These are loose riveted and bolted connections, leakage of the stuffing box, rubber seals, etc.
The sizes of the holes can also vary, from small gaps in sealing joints that do not pose an immediate danger to the survivability of the vessel, to large holes that threaten the death of the yacht and crew. After assessing the size and nature of the damage, immediate measures must be taken to repair them.
Hull holes
This type of accident is one of the most common reasons loss of ships. They differ in shape, size and location. Each type of hole has its own sealing methods. Medium and small holes can be repaired from inside the vessel using available means. Large holes often require the installation of a patch outside the vessel.
A large leak can lead to the death of even a large ship in a matter of minutes, not to mention small ones. sailing boats. To eliminate it, the following procedure should be used:
- Reduce the speed of the vessel, stop the engine, remove the sailing equipment. If possible, you need to turn the yacht with the hole downstream or downwind.
- Start searching for the leak and examining it. Clear the hole from all objects and structures that interfere with its repair: internal lining, floors, furniture.
- Using all means at hand, you need to quickly block access to sea water inside the vessel, or try to reduce it as much as possible. For these purposes, any suitable items are used: mattresses, clothing, life jackets, upholstery stripped from furniture.
- At the same time, the rest of the crew must take emergency measures to combat the survivability of the vessel. Begin removing water from the housing using all available means.
- After preliminary sealing of the leak, without ceasing to remove the incoming water, you need to proceed with the major installation of the leak.
The easiest way to seal a large hole or several smaller ones, located next to each other in the body, is to seal it with a plaster. These can be hard or soft patches. They are made in advance and are included in the yacht's emergency kit. For the base of a rigid plaster, a piece of thick plywood or a plank board is suitable. A layer of soft rubber, a thick blanket or tow wrapped in canvas is stuffed onto it. The soft patch consists of a piece of canvas with eyelets located around its perimeter. To ensure that the patch does not float up when applied to the hole, weights are sewn onto its edges.
Placing the patch
A rigid patch is installed on the hole with inside sides. The following sequence of actions must be followed:
- We clear the area around the hole from all objects that interfere with the work: furniture, parts of the interior lining.
- Often the edges of the holes in metal cases are bent inward, which interferes with the tight fit of the patch to the walls. In this case, you need to quickly straighten the concave edges, or bend them outward using a sledgehammer or the butt of an ax.
- We install the patch in place of the hole with the hard shield facing up and the soft side towards the board.
- We fix the patch over the hole using any available or most convenient methods. Self-tapping screws and nails may be suitable for this - for wooden case, or improvised spacers - for metal or fiberglass. Spacers can be made from pieces of internal furnishings, floor boards, resting one end against the shield and the other against the ceiling of the cockpit, or against the opposite wall. The spacers should also be secured with nails or self-tapping screws to prevent them from weakening and falling out during rocking.
In the absence of a pre-prepared rigid plaster, it can be quite quickly constructed from pieces of the inner wood paneling and the same life jackets, you need to prop up the entire structure with a board.
A soft patch is installed outside the body, above the hole. To do this, a pre-prepared piece of tarpaulin with the ends inserted into eyelets on both sides is placed under the vessel. It is generally recommended to start from the bow of the boat to avoid the patch getting caught on the propellers, rudders or keel. For the same purposes, weights are sewn around the perimeter of the panel: nuts and bolts large diameter, canvas bags with pebbles, etc. To make it more convenient to determine the location of the soft patch under water, a marked end is attached to its upper edge.
When the soft patch is brought to the outer side of the board in such a way that the hole is in the center of the panel, it is attracted by means of cables attached to its edges. On small boats this procedure is done manually, but on large yachts you can use mechanical blocks and hoists. As soon as the hull of the vessel is tightly sealed with a plaster and the flow of sea water has stopped, its ends are securely fastened to the deck. All work on installing the patch should be done as quickly and smoothly as possible, for which it is a good idea to carry out preliminary training for the team. The part of the crew not directly involved in its installation must continuously remove water coming from outside from the yacht’s hull.
Other ways to seal a leak
Smaller holes can be plugged with the same available means (clothing, mattresses, vests), covering them with boards and securing them with spacers. Gaps formed between the hull sheathing sheets can be sealed using dry wood wedges. When wet, the wedges hammered close to each other will swell and close all the gaps in the crack. In a similar way, you can temporarily plug a fallen rivet.
Another way to seal small holes is with so-called cement boxes. They are used both for reliable fixation of rigid adhesives and as an independent means of eliminating leaks. Cement boxes are a frame made of boards. This frame is installed above the hole, previously sealed using available materials. Special quick-hardening cement is poured into the frame and filled with water. You can install a box on a small hole without pre-sealing. For this purpose in through hole a piece of metal pipe is hammered in to drain water, a frame is installed and filled with cement. After this, the drainage pipe is plugged from the outer end.
A common cause of leaks is the lack of tightness of gaskets, seals, and pipeline valves. To eliminate such accidents, you need to have on board repair kit from pieces of soft rubber, sealing seals, tarred tow. Tubes with failed valves can be plugged using previously prepared plugs made of soft wood, wrapped in canvas or tarred tow. These plugs should be attached near each tap to quickly eliminate the malfunction.
Prevention
In order to prevent unpleasant surprises, a preventative inspection of the vessel should be carried out before each trip to sea. Any leaks of oil seals and gaskets must be eliminated in advance, and all poorly functioning water stop valves must be replaced with new ones. Loose rivets are drilled out and replaced with others or bolts with rubber gaskets. Special attention Before going to sea, the crew should be given training on how to act in an emergency. The speed of liquidation of the accident, and therefore the lives of the people on board, largely depends on this.
5.1. General provisions, nature of damage. The location of water entry and the nature of damage to the hull depend on the circumstances (collision, grounding, explosion, pile-up, etc.). Such damage appears quite clearly and is relatively easy to detect.
It is more difficult to establish the cause and location of water leakage when fatigue cracks and fistulas appear, divergence of seams in steel structures, or damage to pipelines.
Characteristic signs of water entering the hull are: the appearance of a static list of the vessel, a change in the nature of the motion under constant external sailing conditions, a noticeable change in the draft of the vessel, a roll of the vessel when the rudder is shifted.
Indirect signs: noise of air being forced out of the compartment through leaks or air pipes; appearing bulges in the bulkheads.
Making a decision to drain an already flooded compartment is a crucial moment, since calculations show that different physical laws apply when flooding and draining compartments.
It is possible to quickly deal with water only in case of small holes, when the time of flooding of the compartment is measured in hours, which makes it possible to clearly prepare and carry out all the operations to seal the hole and drain the compartment.
The fight against water involves solving three problems: preventing the spread of water throughout the ship, since almost all transport ships remain buoyant only when one compartment is flooded; sealing
holes different ways depending on the nature of the damage; removal of water that has already entered the vessel.
There are two ways to repair a hole - from the inside and from the outside.
Repairing the hole from the inside does not require stopping the vessel and allows you to quickly launch emergency work to eliminate water leaks. But in many cases the use of this method is unrealistic the following reasons: work is hampered by hydrostatic water pressure; the edges of the hole are most often bent inward and have a ragged shape; the hole may be in hard to reach place; with medium and large holes, flooding of the compartment occurs very quickly, and it is not possible to drain the compartment using ship drainage means.
Sealing a hole along the outer contour- applying a patch - possible even with large holes, regardless of the area of damage.
5.2. Seal small holes and cracks. Minor water leakage caused by cracks, fallen rivets and poor tightness of joint seams structural elements external cladding can be removed in various ways, the most typical of which are as follows.
Sealing with emergency wedges and plugs(Fig. 1.3, a): wedge 1 (or conical plug 2), wrapped in tow, oiled or soaked in red lead, is driven into the crack (or hole from a fallen rivet) with a sledgehammer. Sealing should begin from the widest part of the crack; as it narrows, the thickness of the wedges decreases. The gaps between the wedges and very narrow areas The cracks are caulked with strands of oiled or red lead-impregnated tow. With low water pressure, the work can be done by one person, and with high pressure - at least two people.
Narrow, “tearing” cracks can be sealed with mastic, heated to a dough-like state and composed of seven parts coal tar and one part sulfur with the addition of slaked lime.
The hole from the fallen rivet is sealed cork(described above) or swivel head bolt(Fig. 1.3, b): bolt 3 is inserted into the hole in the casing 7, while head 6 rotates spontaneously, a wooden spacer 5 and washer 4 are placed on the inside.
Attaching a wooden shield on the hole (Fig. 1.3, c): on the hole in external cladding 7, a wooden shield 9 is placed with a mat 8 attached to it. A wooden spacer 5 is installed on the shield, against which the spacer beam 10 rests. The other end of the beam rests against the foundation 11 of the mechanism and is wedged with wedges 1.
Rice. 1.3. Repairing small holes: a - emergency wedges and plugs; 6 - with a bolt with a rotating head; c - wooden shield; g - a pillow with a tow; d - felt mat or wooden shield; e - emergency clamp; 1 - wedges; 2 - conical plug; 3 - bolt; 4 - washer; 5 - wooden spacer; 6 - bolt head; 7 - casing; 8 - checkmate; 9 - wooden shield; 10 - spacer beam; 11 - foundation; 12 - pillow with tow; 13 - bulkhead; 14 - construction bracket; 15 - wooden shield; 16-felt mat; 17 - clamp; 18 - screw; 19 - capture; 20 - frame; 21 - wooden plaster
Sealing pillow with tow(Fig. 1.3, d): for a hole or crack in the outer skin 7 of the vertical
steel structure a pillow 12 with a tow is placed and pressed through a wooden spacer 5 with a spacer beam 10, which rests against the bulkhead 13 and is wedged with wedges 1.
Sealing felt mat or wooden shield(Fig. 1.3, d) cracks and holes in the bottom of the ship: using construction bracket 14 spacer bars 10 are fastened in the form of the letter “T”. A felt mat 16 or a wooden shield 15 is placed on the hole (crack). The fastened beams are lifted and wedged with wedges 1, resting on the ceiling.
Repairing the hole with emergency clamp(Fig. 1.3, f): a wooden patch 21 with soft upholstery is installed on the hole in the outer skin 7. The clamp 17 is attached to the frames 20 with grips 19. The patch is compressed with a screw 18 through a wooden spacer 5.
Other options for sealing small holes are possible: using a rigid wooden patch and a sliding metal stop or a box-shaped patch and a hook bolt, etc.
5.3. Repairing pipeline damage. The causes of pipeline damage can be: natural aging and wear; external forces - shock during an accident, explosion; violation of technical operation rules - water hammer, freezing of the highway, etc.
Nature of pipeline damage: cracks, fistulas, damage to gaskets, loose connections.
In ship conditions, several methods are used to eliminate damage to pipelines.
Welding damage (fistulas, cracks and small holes) is a quick and reliable way to restore the functionality of a pipeline. To ensure quality welding, the damaged area must be thoroughly cleaned. The pipeline through which petroleum products are pumped must be washed and steamed, and, if necessary, additionally degassed. Depending on the location and nature of the cargo being transported, the conditions of loading and parking of the vessel, welding work sometimes it is impossible.
Thickening of damaged areas(Fig. 1.4, a) are usually used if the use of other methods is not possible. Wire 2 is laid on pipeline 5 in rings tightly adjacent to each other (types I, II) using a special blade 1 (types I, III). Depending on the working environment, before calving, only rubber 4 or additionally a steel pad 3 is applied to the damaged area.
When repairing damage on pipeline bends (Fig. 1.4, b), use gaskets made of soft rubber with plates made of sheet brass 6.
Yoke overlay(Fig. 1.4, c) is the most common, convenient and reliable way to eliminate pipeline damage. There are several types of yokes: universal, tape, tape yokes-clamps, hinged and sliding, chain yokes with bolts with linings.
Rice. 1.4. Repairing pipeline damage: a - by slandering; b - using gaskets; c - by applying yokes; 1 - blade; 2 - wire; 3 - steel plate; 4 - rubber gasket; 5 - pipeline; 6 - plate made of sheet brass; 7 - yokes
Yoke lining technology:
Thoroughly clean the damaged area and remove the insulation;
align the edges of the damage, bending all the burrs inward;
drive plugs or wedges made of mild steel, wrapped in rags greased with red lead, into the damaged areas; cut off or saw off the protruding parts of the plugs flush with the surface of the pipeline;
coat the sealing area with mastic and apply gasket 4 so that it covers the damage by 40-50 mm (the material of the gasket depends on the medium carried by the pipeline);
Place a 2-3 mm thick red copper or mild steel overlay on the gasket, curved around the circumference of the pipe;
apply one or more yokes 7 and compress them by tapping them with the handbrake; if there are several yokes, then the tightening is done from the middle to the extreme.
Installation of plugs on pipelines is carried out only in cases where it provides the opportunity to turn on a boiler that has been taken out of operation, to put into operation one or another important mechanism, or to eliminate steam in a compartment in which the presence of people is necessary.
5.4. Combating the spread of water throughout the vessel, strengthening structures. Filtration of water from a flooded compartment to adjacent ones occurs through leaks in watertight bulkheads and closures: cracks, fistulas, ruptures, damage to seals.
To prevent the spread of water throughout the ship when one of the compartments is flooded, it is necessary to carefully check the water tightness and strength of the bulkheads on the side of adjacent compartments. In this case, it is necessary to take into account the load acting on the watertight bulkhead 4 due to the hydrostatic pressure of water that flooded the adjacent compartment (Fig. 1.5). The pressure of water on a watertight bulkhead affects the unsinkability and stability of the vessel. Most transport ships retain a reserve of buoyancy when only one compartment is flooded, so partial or complete flooding of an adjacent compartment can lead to the death of the ship as a result of loss of buoyancy. When water filters into adjacent compartments, large free surfaces of water can form in them, which will adversely affect the stability of the vessel.
Rice. 1.6. Bulkhead reinforcement: using beams and wedges (a) and strengthening the door using beams and a sliding stop (b): 1 - beams; 2 - wedge; 3 - sliding stop
The fight against the spread of water begins with the external structures enclosing the flooded compartment, while the main attention should be paid to compartments with large volumes and compartments that are vital to the vessel.
If signs of damage to the strength and waterproofness of the bulkheads (bulges, cracks, loose seams) appear, it is necessary to reinforce the bulkheads using sets of beams 1 (Fig. 1.6, a). To avoid bulging of the bulkhead web, the support of the beams should be on the elements of the set.
If necessary, reinforce the door (hatch) leading to the flooded compartment (Fig. 1.6, b). For this purpose they use wooden beams 1 and sliding stops 3. The reinforcement bars are wedged, for which wedges 2 are hammered in with sledgehammers.
When choosing a reinforcement scheme for watertight ship structures, all factors must be taken into account: location, nature, extent of damage; effective loads; complete set of ship emergency equipment; the ability to access damaged areas and their design features.
5.5. Placing the patch. A soft patch is placed when large sizes holes, when it is impossible to drain a flooded compartment without first sealing the hole.” Before applying the patch, it is necessary to accurately determine the location of the hole, which can sometimes only be done with a diving inspection of the damaged area.
To bring the patch to the hole and install it on it, use special equipment (Fig. 1.7, a): keel ends 5, sheets 3, guys 1, control pin 7. The keel ends are made of soft steel rope, and the sheets and guys are made of vegetable rope; on the chainmail patch, the sheets and guys are steel.
To apply the patch, the following operations are performed sequentially (see Fig. 1.7, a, b):
Rice. 1.7. Installation of a soft patch: 1 - guy; 2 - hoist; 3 - sheet; 4 - rope to the hoist (winch); 5 - undercut ends; 6 - patch; 7 - control pin; 8 - false frames; A, B - positions of the under-keel ends
bring the under-keel ends 5 from the bow of the vessel, gradually etching and displacing them along the sides (positions A and B), and bring them to the hole; the keel ends can also be inserted from the stern, depending on the location of the hole, but they can get caught on the propeller blades or rudder blade; the operation of inserting the under-keel ends is very labor-intensive, and a sufficient number of people must be provided for each under-the-keel end;
simultaneously with the installation of the under-keel ends, patch 6 is laid out on the deck in the area of the frames that determine the position of the hole;
the lower luff of the patch is taken overboard and the under-keel ends are attached to the lower corner thimbles using staples;
sheets 3 are attached to the upper corner thimbles, and guy ropes 1 are attached to the middle side thimbles, and they begin to select the keel ends from the opposite side with hoists 2 or winches, pulling the sheets and
the patch is lowered overboard until it closes the hole, the position of the patch in depth is established according to the control pin 7, which is spaced every 0.5 m;
after installing the patch on the hole, the sheets and guys are attached and pulled tightly under the keel ends - the patch is pressed against the hole by the hydrostatic pressure of water, stopping the flow of water into the hull of the vessel;
if the hole is large, then in order to avoid pressing the plaster into the compartment, false frames 8 are inserted simultaneously with the under-keel ends - tightly covered steel ropes, passing through the plane of the hole (see Fig. 1.7, b).
5.6. Setting up a cement box. Concreting and placing a cement box allows you to completely eliminate water leakage and creates the necessary conditions to continue swimming.
Sequence of operations for setting up a cement box (Fig. 1.8, a, b):
temporarily seal the hole (crack) using one of the methods discussed above: placing wedges,
installing hard shields or patches various designs, placing a soft patch;
Rice. 1.8. Placing a cement box on the hole: a - bottom; b - onboard; 1 - emphasis; 2 - formwork; 3 - drainage pipe; 4 - hard patch; 5 - wedges for emphasis; 6 - wedge for a hole.
make and install formwork 2 - install a wooden rectangular box without two edges with side ribs to the hole, the upper open part is used to load concrete; after installation, ensure rigid fixation of the box by installing stops 1 and wedges 5;
clear out metal surface in the area of damage from dirt, rust, traces of petroleum products;
install drainage (water drainage) pipes 3 in case of possible water filtration so that one end of the pipe is brought to the place of filtration, and the other goes beyond the formwork; the diameter of the pipe should ensure free drainage of water and prevent its accumulation;
for large holes along the damaged area, reinforcement made of steel rods or pipes can be secured;
make a creation - low-sided wooden box for preparing concrete; prepare concrete;
fill the formwork with concrete solution so that it is evenly distributed throughout the entire volume of the cement box; concreting must be done as quickly as possible, since if there are accelerators in the solution, it begins to harden within a few minutes; slow, intermittent supply of concrete can lead to delamination of the monolith;
delete drainage pipes after the concrete has hardened, fill the holes with wooden wedges 6;
After the concrete has completely hardened, remove the soft plaster, which will allow the vessel to move.
Concrete preparation technology:
prepare a dry mixture of cement and sand in a ratio of 1:2 or 1:3, thoroughly mixing it with shovels; Portland cement of a grade not lower than 400 (400, 500, 600) is used - these numbers mean permissible load for concrete in the unit kgf/cm; the cement should be in a powdery state, without lumps or grains; the sand must be coarse-grained, river or quarry; the use of fine-grained sand is undesirable;
add water in small portions and mix thoroughly; A concrete solution that easily slides off a shovel is considered normal; if there is too much water, the concrete sticks to the shovel; if there is not enough water, it is difficult to mix; the amount of water directly affects the setting speed of the solution and the strength of concrete; recommended to use fresh water, since sea water reduces the strength of concrete by 10%;
Before preparing the solution, add a hardening accelerator to the water, which can be used: liquid glass (add up to 50% of the total volume of the mixture); calcium chloride (7-10%), caustic soda (5-6%), hydrochloric acid (1-1.5%); with increasing dosage of the accelerator, the strength of concrete decreases, however, in emergency situations, the decisive factor is the speed of its hardening; at low temperatures, concrete should be mixed in heated water (not lower than 30 ° C); if the water is fresh, add salt to it at the rate of two handfuls per bucket; add filler (gravel, crushed stone, broken brick, slag); the filler increases the strength of concrete, but, as a rule, it is not used in ship conditions.
All preparatory work the installation of the cement box must be done in advance, which will ensure quick completion of the main work and high quality concreting.
6. Fighting steam. The ship has a boiler plant with a steam pipeline, which, if damaged, creates an emergency situation. The most typical damage includes: the formation of fistulas and cracks due to natural wear and tear; punching gaskets, loosening fastenings; rupture of a steam pipeline as a result of hydraulic shock.
Damage to the steam line leads to steam leakage, which threatens dangerous consequences: steam displaces oxygen from the room and sharply increases the temperature; having high humidity, it can damage electrical equipment; In case of leaks in cargo holds, steam with dust from some cargo forms an explosive mixture.
Fighting steam is one of the forms of fighting for the survivability of a ship, and the ship's alarm schedule must provide for specific actions of the crew in this case.
Each crew member who discovers a steam leak must immediately report it to the watch officer or engineer and, observing all safety measures, begin to eliminate the damage.
The officer of the watch announces a general alarm indicating the emergency room and the need to comply with safety measures.
The mechanic on watch is obliged to: disconnect the damaged section of the steam pipeline; take measures to protect people from damage by steam, and, if necessary, remove them through emergency exits, protecting them with water spray; open all skylights and ventilation vents leading to the open deck; turn on all forced ventilation to create air pressure; begin repairing the damage.
