When carrying out a ship-lifting operation, the holes are sealed temporarily, only so that the ship can be brought to the repair point, where it is given the appropriate repair.
Seal with external plaster
In river practice, soft plasters are usually used, made of canvas in one or two layers. Plasters are made in square sizes 1.5 X 1.5 m, 4.5 X 4.5 m and 6 X 6 m. Along the edges of the canvas, it is sheathed around a lyktros, from which loops with thimbles are made at the corners of the patch. The ends of the hemp cable with a circumference of about 75 mm are fixed behind the thimble, using which the patch is brought into place and fixed to the vessel.Laying tow between two layers of canvas in a patch cannot be considered rational, as this causes rapid decay of the patch and its failure.
To close a hole in the ship's hull, the patch is brought from the outside of the hull and, if possible, is pressed against it by the ends of the foundling. If at the same time you start pumping water from the damaged compartment, then the pressure of the water will press the patch against the hole and stop the flow of water into it.
The patch is wound in the following order. On both sides of the damaged area of the hull, keel ends are wound up, through which tied to two adjacent corners plaster the ends of the cables. Choosing these ends from the opposite side, they drag the patch so that its middle is against the hole. Then the ends are pulled tight and fixed to the sides of the vessel.
The disadvantage of these soft patches is that if the hole has sharp outward protruding edges, the patch can be easily torn. IN equally a soft plaster cannot stop the flow of water through a hole if the dimensions of the latter are very large, since in this case the plaster will be forced into the vessel by the pressure of the water.
In such cases, instead of a soft plaster, the so-called Swedish plasters are used, made from two or three layers of boards 50-75 mm thick, between which canvas and tar tow are laid. In places where the Swedish patch is attached to the body, wooden planks are sewn, upholstered soft pillows for a tighter fit. To neutralize the positive buoyancy, metal weights (usually pieces of old chains) are suspended from the patch.
To close especially large holes, the wooden plaster is shaped like a box. Such a patch is called a caisson. The caisson is fastened with 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 vessel is made as follows. A layer of tar tow is applied to a piece of canvas or an ordinary bag, exceeding the area of the hole by about three to four times; the tow is smeared on top with an even layer of grease, on top of which a layer of tow is placed again, and canvas again on top. Such a patch is easily tied up and down with a thin twine or cable. The total thickness of the patch is about 5-8 cm. The patch is placed on the damaged area of the hull, and trimmed boards 50-75 mm thick are placed on top. It is better to hammer these cuts tightly between any parts of the hull set, 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 tightly burst into beams, carlings or other reliable connection of the hull.If the leak through the hole is not so strong that it could prevent the installation of the internal patch, then sealing in the manner described can withstand a rather long passage of the vessel quite reliably.
Closing with an external swab
Tampons are used for temporary plugging of small holes, and especially in cases where the winding of patches is not possible. A tampon is made in the same way as an internal plaster, and is brought to the hole by a diver outside the vessel. When the tampon is brought in, water must be simultaneously pumped out, since only under this condition the tampon will be pulled up to the hole, partially penetrate the hull and stop water from entering the vessel.If the diver cannot approach the hole, then the tampon is tied to a fairly long stick on a string about 30-40 cm long, counting from the end of the stick to the tampon. With this stick, the diver drives a swab under the hull in the area of the hole until a jet of water pulls it up and clogs the hole. In this case, of course, the water from the vessel must be pumped out. Sometimes winding a tampon can be done by driving it on a long stick, from a boat, or even from the emergency ship itself,
Having achieved the cessation of water access to the vessel, they completely pump out and close up the hole from the inside, after which the tampons themselves fall off.
Wood patches
Small cracks and holes in the outer hull, open joints and grooves in the skin can be temporarily sealed by a diver using wooden wedges hammered from the outside of the vessel. The wedges are made from dry wood in order to increase the density of the embedding after swelling in water.Wooden wedges are a temporary measure and must be replaced immediately after the ship arrives at the repair point.
A slight leak through small cracks along the parted grooves and joints of the outer skin can sometimes be stopped by letting it in from the outside of the vessel against the leak sawdust, bran or litter from ant heaps: small parts of wood or bran clog and crevices, swell and the flow stops.
It goes without saying that similar way the stoppage of the leak is temporary, suitable only for the time of a short transition of the vessel to the repair point.
Yemeni seal
Cement sealing is reliable not only in drained! hold, but also under water. In the latter case, for reliable sealing, the work on laying cement must be carried out with great care. When repairing damage, fast-setting grades of cement should be used to avoid unwanted erosion and leaching. Before laying the cement, the damaged area must be carefully, to a shine, cleaned of paint and rust and washed with green soap. It is not recommended to touch the gland prepared in this way with hands, so as not to apply a layer of fatty substances and not cause cement to lag. To prevent the cement from spreading, it is necessary to arrange the formwork from the boards around the entire damage.It is much more difficult to cement if water continues to flow through the damage, which easily punches a channel for itself in a freshly applied layer of cement. In such cases, you must 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 dense (clogged with a cork,
In case of large damage that caused the weakening of the hull, it is necessary to lay a frame of iron rods, wire or pieces of iron inside the cement, increasing 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 setting speed. The less sand, the faster the setting is usually.
To reduce the leaching of concrete with water during its setting and to speed up this process, concrete should be mixed in warm water, to which is added liquid glass. After laying the concrete in the formwork, it must be well compacted, which ensures greater water tightness during hardening.
It is not necessary to 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:
clay embedment
Clay sealing is not durable and is used only as a temporary measure to stop the leak until a more reliable repair of the damage. This method is completely inapplicable if any significant amount of water continues to flow into the hole.When muffled from the outside with a plaster; water flow, the work is carried out as follows. Around the damage, formwork is arranged as densely as possible from boards, and individual boards should fit as closely as possible to the shape of the parts of the hull to which they adjoin. Clay is laid in layers and compacted tightly into the formwork. The thicker the layer of clay, the more reliable the seal. It is useful to lay some layers of clay mixed with fine 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 damage site, which are carried away by water jets into the hole, fill individual slots in the seal, swell and thereby: stop or greatly reduce the flow of water into the vessel.
Forward
Table of contents
Back
Sealing damage to the hull with concrete has significant advantages over other methods, because. differs in reliability, durability and tightness. By concreting, it is possible to close up such damage to the hull of the vessel, which would simply be impossible to repair by other means. For example, practice has shown that in most cases only by concreting it is possible to restore the tightness of the flooded compartments of a ship sitting on stones or rocky soils. By concreting it is also possible to close up damage in hard-to-reach places of the vessel, for example, under the foundations of machines and mechanisms, in the fore and after peaks and on the cheekbones.
Concreting of hull water leaks also has the advantage that this method can achieve absolute impermeability of damaged areas, while other temporary seals may not provide this. With the help of concrete, any damage can be repaired - from a slight violation of the rivet joints to large breaches in the bottom or sides.
Years of experience and observations have shown that properly executed loaf embedding lasts a long time, firmly and often eliminates the need for immediate docking of ships.
For the preparation of concrete, sand, gravel, broken brick or in last resort slag.
The recipe and method for preparing concrete mixes are given in the manuals for maritime practice. Mechanical properties concrete based different varieties cement table.
Note. The numerator shows the hardening strength in water, the denominator - in air.
There are 2 types of concreting: air and underwater.
During air concreting, damage is laid sheet metal, around which formwork is made, filled with concrete.
During underwater concreting, the water flow is first diverted from the hole so that it does not erode concrete mix before the mixture sets. To drain water, a drainage tube is installed, which, after the concrete has hardened, can simply be plugged.
Concreting of damages in the bottom, 2nd day, deck does not differ from concreting of side damages.
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, the damaged connections are replaced or the holes are welded. To ensure greater safety of navigation, sometimes at the request of the Register concrete embedment on the ship's hull they are scalded, i.e. concluded to be welded to the body steel box. At the same time, if possible, the crack itself or the open seam in the ship's hull is welded from the outside or from the inside.
The sheets forming the wall of the box around the concrete embedment or cement box are usually welded directly to the ship's hull or framing. Then all the free space of the cement box is filled with a new mortar and welded on top with patch sheets.
If concreting is carried out in the port, then the concrete seal must be welded. A steel box with a tube welded into it by welding is attached to the ship's hull, filled with large aggregates and concrete is laid on top with a steel sheet.
Various options concreting damage after pre-sealing from inside the ship in any way is shown below.
The plasters used as emergency equipment are soft, wooden, metal and pneumatic.
Soft plasters are wound to temporarily seal the hole in order to drain the flooded compartment and then reliably restore the water tightness of the hull. The most durable soft patch is the chain mail patch. It is elastic, adheres 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 interlaced rings made of flexible galvanized steel cable with a diameter of 9 mm.
Lightweight patch measuring 3x3 m consists of two layers of canvas with a felt pad between them. To stiffen the patch, 25 mm steel pipes or a 20 mm steel cable are attached parallel to the upper edge at half-meter intervals from its outer side.
The stuffed plaster (2x2 m) is made of two-layer canvas and a stuffed mat stitched on the inside with a dense dense pile outside.
The patch-mattress can be made by the crew on board. For this canvas bag the right 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 obtained in this way, and a steel cable for winding is nailed to them with building brackets.
Wooden rigid plaster is usually made on the ship "in place" after receiving a hole in the hull. It is most advisable 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 to seal small holes from the outside at a depth of up to 10 m.
3.1. Installing a metal patch with a clamping bolt pb1.
Holes with a diameter of 35 - 100 mm with a torn edge height of up to 15 mm can be repaired metal patch with clamping bolt PB-1. The patch can be applied by one person, and does not require additional fastening after installation. On the ship, the PB-1 patch (Fig. 5) is stored in a permanent readiness for use, assembled, the nut with handles should be located in the upper threaded part of the clamping bolt.
To install the patch on the hole, you must:
install the swivel bracket, overcoming the force of the spiral spring, parallel to the axis of the clamping bolt;
insert the clamping bolt with the swivel bracket into the hole so that, having gone beyond the skin, it turns under the action of the spring perpendicular to the axis of the clamping bolt;
holding the patch by the bolt, by turning the nut by the handles, press the rubber seal with the pressure disk against the skin until the water leak from the hole is eliminated.
The non-working surfaces of the patch are painted with red lead, the workers (clamping bolt, spring, nut thread) are lubricated with grease, the rubber seal is covered with chalk.
The cause of a leak on a yacht can be a variety of malfunctions: holes, open seams, leaky sealing glands, etc. Regardless of the cause, any leak poses a serious danger to the vessel and its crew. In this regard, upon detection of outboard water entering the yacht, all measures should be taken immediately to eliminate this malfunction.
Cause of the leak
In the arsenal of modern sailors there is a large number of ways and means to eliminate the outboard leak. The use of one or another housing sealing technology depends on the cause of the leak. Before proceeding with the liquidation of the accident, it is necessary to 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:
- through mechanical damage hulls due to impact on stones, on a pier, on another ship, as a result of grounding, the impact of storm waves. Such damages include: holes and cracks in the hull, parted seams.
- Housing depressurization due to technical malfunctions and physical wear and tear of components and parts. These are loose riveting and bolted connections, leakage of gland packing, rubber seals, etc.
The size of the holes can also be different, from small gaps in the sealing joints, which 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 causes ship wrecks. They differ in shape, size and location. For each type of holes, their own sealing methods have been developed. Holes of medium and small size can be repaired from the inside of the vessel using improvised means. Large holes often require the installation of a plaster on the outside of the vessel.
A large leak can in a matter of minutes lead to the death of even a large vessel, not to mention small ones. sailboats. To eliminate it, the following procedure should be used:
- Reset the course of the vessel, stop the engine, remove the sailing equipment. If possible, you need to turn the yacht with a hole downstream or downwind.
- Start searching for the leak and inspecting it. Free the place of the hole from all objects and fittings that interfere with its sealing: inner lining, floors, furniture.
- With the help of all the means at hand, you need to quickly block the access of outboard water to the inside of the vessel, or try to reduce it as much as possible. For these purposes, any suitable items are used: mattresses, clothes, life jackets, upholstery torn from furniture.
- At the same time, the rest of the crew must take emergency measures to combat the survivability of the ship. Start removing water from the hull using all available means.
- After the preliminary sealing of the leak, without ceasing to remove the incoming water, it is necessary to proceed with the capital installation of the leak.
A large hole or several smaller ones located next to each other in the body are easiest to patch with a band-aid. These can be hard or soft patches. They are made in advance and are included in the emergency kit of the yacht. A piece of thick plywood or a plank shield is suitable for the base of a hard patch. A layer of soft rubber is stuffed on it, a thick blanket or tow wrapped in canvas. A soft plaster consists of a piece of canvas with eyelets located along its perimeter. In order for the patch not to float to the hole when winding, weights are sewn onto its edges.
Plastering
A hard patch is installed on a hole with inside sides. You must follow the following sequence of actions:
- We clean the place around the hole from all objects that interfere with the work: furniture, parts of the inner lining.
- Often the edges of the hole in metal cases are bent inward, which interferes with the tight fit of the patch to the walls. In this case, it is necessary to quickly straighten the concave edges, or bend them outward with a sledgehammer or an ax butt.
- We install the patch in place of the hole with a solid shield up, and with the soft side to the board.
- We fix the patch over the hole by any available or most convenient means. 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 fittings, floor boards, resting them with one end against the shield, and with the other against the cockpit ceiling, or against the opposite wall. The spacers should also be fixed with nails or self-tapping screws to prevent them from loosening and falling out during pitching.
In the absence of a pre-prepared hard plaster, it can be quickly built from pieces of the inner wood paneling and the same life jackets, you need to spread 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 passed through the eyelets on both sides is wound under the vessel. It is generally recommended to wind from the bow of the boat to avoid the patch getting caught on the propellers, rudders or keel. For the same purposes, loads are sewn around the perimeter of the cloth: nuts and bolts large diameter, canvas bags with pebbles, etc. In order 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 a soft plaster is brought to the outer side of the bead 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 by hand, but on large yachts, mechanical blocks and hoists can be used. As soon as the ship's hull is tightly pressed with plaster and the flow of sea water has stopped, its ends are securely fastened to the deck. All work on setting the patch should be done as quickly and smoothly as possible, for which it is good to make preliminary team training. The part of the crew not directly involved in its installation must continuously remove water from the outside of the yacht's hull.
Other ways to seal a leak
Smaller holes can be plugged with the same improvised means (clothing, mattresses, vests), covering them with boards and securing them with spacers. The cracks formed between the hull plating sheets can be sealed with dry wood wedges. When wet, the wedges hammered close to each other will swell and close all the gaps of the gap. In the same way, you can temporarily plug a fallen rivet.
Another way to seal small holes is the so-called cement boxes. They are used both for reliable fixation of rigid plasters, and as an independent means of eliminating leaks. Cement boxes are a frame knocked together from boards. This frame is installed above the hole, pre-sealed with scrap materials. A special fast-hardening cement is poured into the frame and filled with water. On a small hole, you can install a box without pre-sealing. For this in through hole a piece of a metal tube is clogged to drain water, a frame is installed and poured with cement. After that, the drainage tube is muffled from the outer end.
A common cause of leaks is not the tightness of gaskets, seals, pipeline valves. To eliminate such accidents, you need to have on board repair kit from pieces of soft rubber, sealing glands, tarred tow. Pipes with failed valves can be plugged with pre-prepared softwood plugs wrapped in canvas or tarred tow. These plugs should be attached near each faucet for quick troubleshooting.
Prevention
In order to prevent unpleasant surprises, a preventive inspection of the vessel should be carried out before each sailing. Any leaks in glands and gaskets should be eliminated in advance, all poorly functioning water shut-off valves should be replaced with new ones. Weakly holding 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 exercises on how to act in an emergency. The speed of liquidation of the accident, and hence the lives of people on board, largely depends on this.
5.1. General provisions, nature of damage. The place of water ingress and the nature of damage to the hull depend on the circumstances (collision, grounding, explosion, bulk, etc.). Such damages are shown quite clearly, they are relatively easy to detect.
It is more difficult to establish the cause and place of leakage in the event of a fatigue crack and fistulas, divergence of steel structure seams, and damage to pipelines.
The characteristic signs of water entering the hull are: the appearance of a static roll of the vessel, a change in the nature of the roll under constant external conditions of navigation, a noticeable change in the draft of the vessel, the roll of the vessel when the rudder is shifted.
Indirect signs: noise of air displaced from the compartment through leaks or air pipes; bulkhead bulges that have appeared.
The 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 with small holes, when the flooding time of the compartment is measured in hours, which makes it possible to clearly prepare and carry out all operations to seal the hole and drain the compartment.
The fight against water provides for the solution of three problems: prevention of the spread of water throughout the vessel, since almost all transport vessels remain buoyant only when one compartment is flooded; termination
holes different ways depending on the nature of the damage; removal of water that has already entered the vessel.
There are two ways to close a hole - from the inside and outside.
Filling a hole from the inside does not require stopping the vessel and allows you to quickly deploy emergency work to eliminate water leakage. But in many cases, the application of this method is unrealistic due to the following reasons: work is hindered by hydrostatic pressure of water; the edges of the hole are most often bent inward and have a torn shape; the hole may be in hard to reach place; with medium and large holes, the flooding of the compartment occurs very quickly, and it is not possible to drain the compartment with ship drainage means.
Sealing a hole along the outer contour- putting a patch - possible even with large holes, regardless of the area of damage.
5.2. Seal small holes and cracks. Slight water leakage caused by cracks, dropped rivets and violation of the tightness of the seams of the joint structural elements outer skin, can be eliminated in various ways, the most typical of which are as follows.
Termination with emergency wedges and plugs(Fig. 1.3, a): a wedge 1 (or a conical plug 2), wrapped in tow (tow), oiled or impregnated with minium, is driven into a crack (or a hole from a dropped rivet) with a sledgehammer. Embedding should start from the widest part of the crack, as it narrows, the thickness of the wedges also decreases. The gaps between the wedges and very narrow sections cracks are caulked with strands of oiled or minium-soaked tow. With a small pressure of water, one person can do the work, and with a large pressure - at least two people.
Narrow, "watery" cracks can be sealed with mastic, heated to a paste-like state and composed of seven parts of coal tar and one part of sulfur with the addition of slaked lime.
The hole from the dropped rivet close up cork(described above) or swivel head bolt(Fig. 1.3, b): the bolt 3 is inserted into the hole in the casing 7, while the head 6 spontaneously rotates, a wooden gasket 5 and a washer 4 are placed on the inside.
Fastening a wooden shield on the hole (Fig. 1.3, c): on the hole in outer skin 7, a wooden shield 9 is applied with a mat 8 attached to it. A wooden gasket 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. Sealing small holes: a - emergency wedges and plugs; 6 - a bolt with a rotary head; in - a 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 gasket; 6 - bolt head; 7 - sheathing; 8 - mat; 9 - wooden shield; 10 - spacer bar; 11 - foundation; 12 - pillow with tow; 13 - bulkhead; 14 - building bracket; 15 - wooden shield; 16 felt mat; 17 - clamp; 18 - screw; 19 - capture; 20 - frame; 21 - wooden patch
termination pillow with tow(Fig. 1.3, d): on a hole or crack in the outer skin 7 vertical
steel structure a pillow 12 with a tow is applied and through a wooden gasket 5 they are pressed with a spacer bar 10, which abuts against the bulkhead 13 and is wedged with wedges 1.
termination felt mat or wooden shield(Fig. 1.3, e) cracks and holes in the bottom of the vessel: using construction bracket 14 spacer bars 10 fasten in the form of the letter "T". A felt mat 16 or a wooden shield 15 is installed on the hole (crack).
Closing a hole with emergency clamp(Fig. 1.3, f): a wooden patch 21 with soft upholstery is installed on a hole in the outer skin 7. The clamp 17 is attached to the frames 20 with grippers 19. The compression of the patch is carried out with a screw 18 through a wooden gasket 5.
There are other options for sealing small holes: with a wooden hard plaster and a sliding metal stop or a box-shaped patch and a hook bolt, etc.
5.3. Elimination of damage to the pipeline. The causes of damage to the pipeline can be: natural aging and wear; external forces - impact during an accident, explosion; violation of the rules of technical operation - hydraulic shock, freezing of the main line, etc.
The nature of the damage to the pipeline: cracks, fistulas, damage to gaskets, loosening of connections.
In ship conditions, several methods are used to eliminate damage to pipelines.
Welding damage (fistulas, cracks and small holes) is a fast and reliable way to restore pipeline performance. To ensure high-quality welding, the damaged area must be carefully cleaned. The pipeline through which oil 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's impossible.
Cellification of damaged areas(Fig. 1.4, a) are usually used if the use of other methods is not possible. The wire 2 is laid on the pipeline 5 in tightly adjacent rings (types I, II) using a special blade 1 (types I, III). Depending on the working environment, only rubber 4 or an additional steel plate 3 is applied to the damaged area before cageing.
When repairing damage on pipeline bends (Fig. 1.4, b), apply gaskets made of soft rubber with overlays of sheet brass 6.
Overlay of yokes(Fig. 1.4, c) is the most common, convenient and reliable way to repair pipeline damage. There are several types of yokes: universal, tape, tape yokes-clamps, hinged and sliding, chain on bolts with pads.
Rice. 1.4. Elimination of damage to pipelines: a - celling; b - with the help of gaskets; in - the imposition of yokes; 1 - blade; 2 - wire; 3 - steel plate; 4 - rubber gasket; 5 - pipeline; 6 - overlay made of sheet brass; 7 - yokes
Bug overlay technology:
thoroughly clean the area of damage, remove insulation;
align the edges of the damage by bending all the burrs inward;
hammer into damaged places corks or wedges made of mild steel, wrapped in rags smeared with red lead; cut or saw off the protruding parts of the plugs flush with the surface of the pipeline;
smear the sealing place 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);
put on the gasket a lining made of red copper or mild steel 2-3 mm thick, curved around the circumference of the pipe;
apply one or more yokes 7 and crimp, tapping on them with a handbrake; if there are several yokes, then tightening is done from the middle to the extreme.
Stubs on pipelines is carried out only in cases where it provides the opportunity to turn on the decommissioned boiler, put into operation one or another important mechanism, or eliminate soaring in the compartment in which the presence of people is necessary.
5.4. Fight against the spread of water on the ship, reinforcement of structures. Filtration of water from the flooded compartment to the neighboring ones occurs through leaks in watertight bulkheads and closures: cracks, fistulas, ruptures, damage to seals.
In order to prevent the spread of water throughout the ship when one of the compartments is flooded, it is necessary to carefully check the watertightness 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 maintain a reserve of buoyancy when only one compartment is flooded, so that partial or complete flooding of an adjacent compartment can lead to the death of the vessel as a result of loss of buoyancy. When water is filtered into adjacent compartments, large free water surfaces can form in them, which will adversely affect the stability of the vessel.
Rice. 1.6. Bulkhead reinforcements: with the help of bars and wedges (a) and reinforcement of the door with the help of bars and a sliding stop (b): 1 - bars; 2 - wedge; 3 - sliding stop
The fight against the spread of water begins with the external structures enclosing the flooded compartment, with the focus on compartments with large volumes and compartments that are vital to the ship.
If there are signs of a violation of the strength and water tightness of the bulkheads (bulges, cracks, open seams), it is necessary to reinforce the bulkheads using sets of beams 1 (Fig. 1.6, a). In order to avoid bulging of the bulkhead web, the emphasis of the bars should fall on the elements of the set.
If necessary, reinforce the door (hatch) leading to the flooded compartment (Fig. 1.6, b). For this purpose, use wooden bars 1 and sliding stops 3. The reinforcement bars are wedged, for which wedges 2 are hammered with sledgehammers.
When choosing a reinforcement scheme for watertight ship structures, all factors must be taken into account: the location, nature, size of damage; acting loads; complete set of ship's emergency equipment; the possibility of access to damaged areas and their design features.
5.5. Plastering. A soft patch is placed on large sizes holes, when it is impossible to drain the flooded compartment without first sealing the hole. Before starting the patch, it is necessary to accurately determine the location of the hole, which can sometimes be done only during a diving inspection of the damaged area.
To bring the patch to the hole and install on it, special equipment is used (Fig. 1.7, a): keel ends 5, sheets 3, braces 1, control pin 7. The keel ends are made of soft steel rope, and sheets and braces are made of vegetable; on the chain mail patch, the sheets and braces are steel.
To apply the patch, the following operations are sequentially performed (see Fig. 1.7, a, b):
Rice. 1.7. Placing a soft patch: 1 - guy; 2 - hoist; 3 - sheet; 4 - rope to the hoist (winch); 5 - tail ends; 6 - plaster; 7 - control sheet; 8 - false frames; A, B - positions of the tail ends
the keel ends 5 are brought in from the bow of the vessel, gradually easing and shifting them along the sides (positions A and B), they are brought to the place of the hole; keel ends can also be started from the stern, depending on the location of the hole, but they can catch on the propeller blades or the rudder blade; the operation of winding the wing ends is very laborious, and a sufficient number of people must be provided for each wing line;
simultaneously with the winding of the tail ends, a 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 out overboard and the keel ends are attached to the lower corner thimble using staples;
sheets 3 are attached to the upper corner thimbles, and braces 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, easing the sheets and
the patch is lowered overboard until it closes the hole, the position of the patch in depth is set according to the control pin 7, which is broken down every 0.5 m;
after the patch is installed on the hole, the sheets and braces are attached and the tail ends are tight - the patch is pressed against the hole by the hydrostatic pressure of water, stopping the flow of water into the ship's hull;
if the hole is large, then in order to avoid indentation of the patch into the compartment, false frames 8 are brought in simultaneously with the tail ends - tightly fitted steel ropes passing through the plane of the hole (see Fig. 1.7, b).
5.6. Setting up a cement box. Concreting and setting a cement box allows you to completely eliminate water leakage and creates the necessary conditions to continue sailing.
The sequence of operations for setting up a cement box (Fig. 1.8, a, b):
the hole (crack) is temporarily closed by one of the methods discussed above: setting wedges,
installation of rigid shields or patches various designs, setting a soft plaster;
Rice. 1.8. Putting a cement box on a hole: a - bottom; b - onboard; 1 - emphasis; 2 - formwork; 3 - drainage pipe; 4 - hard patch; 5 - wedges for emphasis; 6 - a wedge for a hole.
make and install formwork 2 - install a wooden rectangular box without two faces with side ribs to the hole, the upper open part is used to load concrete; after installation, ensure a rigid fixation of the box by installing stops 1 and wedges 5;
clean up metal surface in the area of damage from dirt, rust, traces of oil products;
install drainage (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 must ensure free drainage of water and exclude its accumulation;
with large holes along the damage area, it is possible to fix reinforcement from steel bars or pipes;
make worked - low-breasted wooden box for the preparation of concrete; prepare concrete;
fill the formwork with a concrete solution so that it is evenly distributed throughout the volume of the cement box; concreting should be done as quickly as possible, since if there are accelerators in the solution, it begins to harden after a few minutes; slow, intermittent supply of concrete can lead to delamination of the monolith;
delete drainage pipes after the concrete has hardened and hammer the holes with wooden wedges 6;
after the concrete has completely hardened, dismantle the soft plaster, which will ensure the possibility of movement of the vessel.
Concrete preparation technology:
prepare a dry mixture of cement and sand in a ratio of 1:2 or 1:3, mixing it thoroughly with shovels; use Portland cement grade not lower than 400 (400, 500, 600) - these numbers mean permissible load on concrete in the unit kgf/cm; cement should be in a powdery state, without lumps and grains; 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; with an excess of water, the concrete sticks to the shovel, with a lack of water, it is difficult to mix; the amount of water directly affects the setting speed of the solution and the strength of concrete; it is recommended to apply 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 as: 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 an increase in the dosage of the accelerator, the strength of concrete decreases, however, in emergency situations, the decisive factor is the rate of its hardening; at low temperatures, concrete should be kneaded 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); filler increases the strength of concrete, but in ship conditions it is usually not used.
All preparatory work for the setting of the cement box must be made in advance, which will ensure the rapid completion of the main work and high quality concreting.
6. Fight against steam. The ship has a boiler plant with a main steam pipeline, if damaged, an emergency situation is created. The most typical damages include: formation of fistulas and cracks due to natural wear and tear; punching gaskets, loosening fasteners; rupture of the steam pipeline as a result of water hammer.
Damage to the steam line leads to steam leakage, which threatens dangerous consequences: steam displaces oxygen from the room and dramatically increases the temperature; having high humidity, can damage electrical equipment; in case of leakage in cargo holds, the vapor with the dust of some cargoes forms an explosive mixture.
Steam combat is one of the forms of ship damage control, and the ship's muster list should provide for specific crew actions in this case.
Each member of the crew who discovers a steam leak must immediately report it to the watch officer or mechanic and, observing all safety measures, proceed to repair the damage.
The watch officer announces a general ship's alarm indicating the emergency room and the need to comply with security measures.
The watch mechanic is obliged to: disconnect the damaged section of the steam pipeline; take measures to protect people from being hit by steam, and, if necessary, take them out through emergency exits, protecting them with water irrigation; open all skylights and ventilation bells leading to the open deck; turn on all forced ventilation to create air overpressure; start repairing the damage.
