Installation of rigid plasters. Elimination of water leakage of the ship hull, ship repair technology, steering gear, classification of ships, transport ships, service and auxiliary ships, technical fleet ships and special ships, hydrofoils.
A damaged vessel often has damage to its outer hull, through which water enters the vessel and causes it to sink. To give the vessel positive buoyancy, it is necessary to repair the damage to the hull and pump out water from the vessel.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 are attached to the thimbles hemp rope with a circumference of about 75 mm, using which the patch is placed in 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 patch is applied with outside body and, if possible, presses 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, hook ends are inserted, through which the ends of the cables tied to two adjacent corners of the plaster are pulled under the ship. 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. 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 patch, 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 such a method of stopping a 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 it is 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 with 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 wooden ships is still a pressing issue for most of their owners. Letters from readers testify to this. Therefore, we hope that the advice of our regular author, design engineer Vladimir Mikhailovich Alekseev, will be useful.
Volume repair work, performed by the owner of the ship or his crew, directly depends on the skills at work and financial capabilities. As the builder masters the necessary repair methods and techniques, he gradually gains experience that allows him to begin increasingly complex work and successfully complete it.
Naturally, at first you should learn a little from a specialist, observing his techniques, helping him, first of all, in repairing structures that ensure strength or tightness.
Caring for the boat in the off-season. During this period, they are usually limited to minor glue work and varnishing. The conditions for good gluing are clean and not too smooth wooden parts. Therefore, it is often necessary to sand surfaces in order to create roughness.
Typically, waterproof epoxy glue is used, as are still rare rubber-like and phenolic adhesives, to, for example, glue a chipped layer of veneer in place. They also use elastic polyurethane glue, the recipe of which was developed back in the USSR, and polyester adhesives of different hardness (they do not shrink, and internal stresses do not arise in their structures)*.
Small cracks and holes are filled with “putty,” which is made from sawdust of the same wood species or microspheres and epoxy glue (it is much more useful and reliable to use wood flour from the desired species of wood, obtained by sanding wooden products). After hardening, the repaired area is sanded, polished and varnished.
Vessel care during navigation. Caring for a wooden yacht during this period can be summarized as follows:
All varnished surfaces are washed fresh water and dry thoroughly;
In good weather, all internal rooms and bilges are ventilated so that they are clean and dry, the body is periodically inspected;
Detected scratches and other damage to the paint, especially on the outside, are immediately preserved, having first removed the rot, and the necessary restoration or repairs are planned in the off-season...
Sand that gets on the ship is immediately removed, since it contributes to the rapid wear of paint and varnish, and when it lingers in the bilges, it helps to moisten them.
When moored, the vessel must be well moored and the hull covered with a cover.
Rot protection. A wooden boat is constantly affected by variable air humidity and temperature, and unprotected wood is susceptible to rotting and fouling. All this taken together contributes to intensive destruction and loss of strength of structures.
The traditional way to protect wood from rotting is to stain it with an antiseptic and carefully paint it, usually with several layers of waterproof paint.
Repairing minor damage.
At the end of navigation, after raising the vessel, it is thoroughly washed, inspected and a list of damage to the paint and darkened layers of wood is immediately compiled. It includes damage that was detected during navigation.
The basis of these works are grinding, preserving and varnishing. The final coats of varnish, paint and antifouling should be applied in the spring, just before the boat is launched, when it has dried well. Naturally, before painting and varnishing, all identified damage should be eliminated and areas with deep scratches should be repaired.
Treatment of open areas. Grind the damaged areas and adjacent areas with a width of about 30 mm (dry grinding, grain - from 100 to 120 units).
Preserve wood with oils or alkyd paints, but only without final varnishing.
Repair of grooves and cracks.
Clean the inner surface of the groove or crack (with a thin steel strip, for example, from an old ruler or saw).
If possible, degrease internal surfaces cracks (for example, acetone).
Cracks less than 1 mm wide are filled with putty using epoxy glue with a thixotropic filler (wood fibers, wood dust from sanding or aerosil).
In cracks more than 1 mm wide, glue a strip of width equal to the thickness of the damaged one using epoxy glue. Wood and its color are selected in accordance with the surface being repaired.
After the glue has hardened, sand the insert from the outside and inside.
Aged wooden surfaces, as described, cleaned and painted earlier.
Seal the grooves. With some cladding methods (for example, smooth) or when laying deck flooring, plant fibers or threads soaked in linseed oil or oil varnish are laid between the slats. When the slats swell from water, the joints become sealed.
If they begin to leak water, the threads should be removed and replaced with thicker ones using a steel wedge. Then the joints are puttied with elastic mastic. Rigid cannot be used, as it will crack and delaminate during elastic deformation of the structure.
It is impossible to seal seams on varnished natural wood in the above-water part of the ship's hull using this method, since the joint putty remains noticeable. Thin (up to 2 mm), uniform joints are left free. Wider joints are sealed in the same way as cracks are repaired.
When repairing deck flooring, elastic mastic is used, which remains elastic for a long time. Joints in sheathing, superstructure coamings, and shearstrake can also be sealed with caulk.
A sign of the onset of rotting is the darkening of the wood around the cork. In this case, it is removed by drilling and replaced with a new one, made of similar wood, but of a larger diameter. After gluing, the cork is cut, cleaned and processed like a new product.
Restoring the coating of the underwater part. Once all minor damage has been repaired, you can begin preparing the surface for varnishing and painting the underwater part. First remove those practical items and equipment parts that are easy to remove.
After this, the deck and outer skin of the vessel are thoroughly sanded using waterproof sanding paper (grain - from 180 to 220) with water by hand or with a flat vibrating machine.
The entire surface should become matte, i.e. leveled. Wet sanding produces a smoother surface and produces less dust. It is preferable to dry grinding.
CAUTION: 1. Surfaces natural wood, coated with colorless varnish, are sanded in the direction of the fibers, and not across them. In this case, it is necessary to avoid removing too much wood. If this happens, carry out work as described earlier.
2. When preparing the underwater part of a ship for painting, only wet sanding is used, since dust from antifouling paint is harmful to health. Immediately after sanding, the surface is thoroughly washed with clean water. If this is not done, then uncleaned dust may stick firmly to the sanded surface.
After one or two days of drying and re-wiping, you can begin the final varnishing or painting. The varnished surfaces are first sanded, very carefully, and dust is removed, including from the smallest recesses.
Otherwise, a brush with sticky varnish will turn all the remaining specks into numerous tubercles or “bristles.” Before varnishing workplace it is necessary to clean thoroughly, moisten the floors with water and provide protection from direct sunlight.
It is better to carry out the work on a calm day with relative humidity air no higher than 75% and air temperature no lower than 12°. Last layer The varnish is applied with brushes that have previously been used, but not with new ones.
The varnish layer should be thin and uniform; oil varnish and alkyd varnish are first applied across the surface, then quickly and thoroughly shaded along the layers of wood. The final coat of varnish should dry for three weeks, but not less than a week.
Large-scale repair work. Before starting such repairs, a work plan is drawn up. The following should be noted:
For repairs, you can only use dry and defect-free wood, always taking into account the necessary strength of the structural elements and the location of the growth rings;
Use only waterproof adhesives;
Remove damaged structural elements, if possible without damaging adjacent areas;
Accurately measure replaced structural elements or make templates; work, whenever possible, according to the drawings of the part being repaired;
The new structural element should be carefully worked out in advance and precisely adjusted to the location;
Prepare in advance the necessary auxiliary devices before installing the part;
Apply protective coatings on the repaired structure, for example, the undersides of frames, floors, deck flooring;
Paint the repaired area.
Repair of clinker cladding.
After inspection, the exact boundaries of the damage are determined. The boards are cut at right angles with a fine-toothed saw.
Rivets, including those passing through the frame, are beaten with a knockout (a thin, narrow strip of steel, sharpened at one end, for example from a saw blade or a rod).
Inserts are made, if possible, from one piece of wood or several parts, but prepared in such a way that the inner part can be pulled out and another made from it; if the sheathing board is destroyed to such an extent that it is impossible to outline a new one, then a paper template is made.
Clean the edges of the board and remove the remaining parts of the rivets with a countersink.
The ends of the boards remaining in the hull are beveled over a length of 3 to 5 board thicknesses so that the bevels face the stern.
Cut a new piece of board to the size of the cut out part, bevel the ends as mentioned earlier, or prepare it according to a template and adjust it to the location.
Putty on drying oil or old thickened varnish is applied to the long edges of the boards, and glue (preferably epoxy) is applied to the beveled surfaces.
The workpiece is put in place using old rivet seams. In the places where the insert is attached to the frames or floors, you will have to drill new holes. After the glue has hardened, the insert is cleaned and preserved.
Replacing boards when sheathing smoothly.
Cut out the damaged part of the board with a jigsaw or a narrow hacksaw (“fox tail”).
Before cutting the ends, you should understand how it will be secured new board: end-to-end on spacers or by bevelling the joints.
The fasteners are removed with steel rods of the required diameter.
The damaged part is released as completely as possible, and if this is not possible, then the corresponding templates are removed.
At the ends, linings, edge bevels, and shaped joints are prepared, and the bevels should have a length of 3 to 5 times the thickness of the boards being repaired. All this should ensure a reliable seal.
The repair site is thoroughly cleaned.
Adjust the workpiece. When directly joining boards at the ends of the workpiece, wooden (duplicating the thickness of the board) or steel linings are provided. It is advisable to make these pads much wider than the board being repaired for reliable fastening with adjacent boards.
Preserve the underside of the frame (with linseed oil, thick varnish) and drive the caulk into pre-prepared grooves in longitudinal grooves boards
Linings are glued (for example, with epoxy glue) to the joints of the glued boards.
The insert is mounted, riveted or adhesive joints are placed on the screws (when connecting boards end-to-end or when joints are beveled), then the boards are either fastened together or attached to the set with the provided fasteners, and if the insert is located above the waterline, then the screw heads are closed with wooden plugs.
Repair of rack sheathing.
They are deciding whether to join or clamp the damaged rail. Bevelling is preferable if homogeneous wood with uniform structure and color is used. Embedding requires certain experience and qualifications, since the joint may become noticeable when the insert is varnished.
Drill holes with a diameter of 5–10 mm and cut out the damaged rail with a jigsaw.
During construction, the slats are glued together and secured with nails so that it is not visible either from the outside or from the inside; You should pay attention to this when cutting out damage along the grooves. It is recommended to use a metal cutting blade near the location of the nails, then it will be possible to avoid damaging adjacent slats.
In the area where the frames or floors are attached, the fasteners are dismantled or simply knocked out.
The insert is adjusted and cut to a miter length; as explained earlier, the damaged area is sanded.
The section of the inserted strip is cut out and adjusted. The lath should be 2–4 mm thicker than the sheathing so that it can be leveled with the surface of the adjacent laths. The width should be 0.5 mm larger so that when putting it in place with glue, it can be pressed tightly between the other slats.
The lower surfaces of the frames and floors are preserved.
Apply glue and press the rail into place using screws, bolts or wedges.
After the glue has hardened, the pressing devices are removed and the insert is cleaned; when bolted, the fastener heads are closed with wooden plugs.
Repair of diagonal cladding.
They clarify whether it is necessary to change the inner layers of the skin along with the outer one or whether it is possible to get by with replacing one layer.
Separate the layers of boards in the area of damage using gravers or remove the damage with an end mill with a diameter of 8–12 mm, set to the thickness of the damaged layer.
The fasteners are knocked out, preferably in the direction where the washers are placed, and the fasteners are released from the frames and floors.
They prepare the repair site, chamfer the joints, clean the grooves and the places where the rivets are installed.
Adjust the workpiece. If the damage site is located on the cheekbone with a large curvature, then the workpiece is steamed, first bent according to a template, then left to cool. It is better to slightly bend the workpiece, because after releasing it from the fasteners, it will straighten out a little. If it is not possible to steam the workpiece, then it is made by gluing several thin boards on a pre-prepared tsulag.
After removing the damaged boards, the condition of the preservative fabric is checked at the site of damage. If necessary, lay new fabric and preserve it with paint.
They put the workpiece in place, glue the bevels, drill out the fastener installation locations from the outside or inside along the old holes, fasten the workpiece, rivet the gaskets with the sheathing boards during direct joining, install the fasteners on the frames and floors.
The repair area is cleaned, polished and preserved.
Repair of plywood sheathing.
Holes are drilled in the corners of the damage using wood drills (with a punch-type end) with a diameter of 8–12 mm, and the damage is cut out with a jigsaw. If the damage is located near the frame or floor, then all fasteners are removed.
Bevel all edges at a length of 3 to 5 thicknesses.
The insert is prepared, the edges are beveled, and adjusted in place.
The workpiece is coated with glue (preferably epoxy) and placed in place, fasteners are installed, and wedged. After the glue has cured, clean it up.
If large loads are expected, for example, during planing, it is recommended to glue a slightly larger backup pad.
Then the repair site is preserved.
Replacing rivets.
Grind the rivet head with a file or emery.
Ship's salvage property. To eliminate water leakage of the hull and various damages, ships are provided with emergency equipment and materials.
The name and minimum quantity of salvage property are established by the standards of the Register of the Russian Federation, depending on the length and purpose of the vessel. Part emergency supplies includes: patches with rigging and equipment, plumbing and rigging tools, clamps, bolts, stops, brackets, nuts, nails, canvas, felt, tow, cement, sand, wooden beams, wedges, plugs, etc. On passenger ships and vessels special purpose with a length of 70 m or more, as well as on ships made of fiberglass, the Rules of the Register of the Russian Federation provide for additional supplies. In addition, all modern large-capacity ships usually have light diving equipment and electric welding equipment.
Emergency supplies, except diving equipment and plasters, must be painted blue: wooden products - completely; beams - from the ends and at the ends (at a length of 100-150 mm); metal objects - on non-working surfaces: plasters, mats, coils of wire - in transverse stripes.
Containers for storing emergency supplies must also be painted blue (either completely or striped) and clearly labeled with the name of the material, its weight and permissible shelf life.
All specified supplies must be stored at emergency posts: in special rooms or in boxes. There must be at least two such posts on the ship, and one of them must be in the engine room (on ships with a length of 31 m or less, storage of emergency supplies is allowed only at one emergency post. Emergency posts must have clear inscriptions “Emergency post.” In addition In addition, signs for the location of emergency posts must be provided in the passages and on the decks.
Emergency equipment that has special markings is allowed to be used only for its intended purpose: when fighting water, as well as during drills and exercises. Any emergency equipment that has been used up or has become out of order must be written off according to the report and, as soon as possible, replenished to normal levels.
At least once a month, commanders of emergency parties (groups) with the participation of the boatswain must check the availability and serviceability of emergency equipment. The results of the inspection are reported to the chief mate. A similar check of emergency property (simultaneously with a check of fire-fighting equipment and life-saving equipment) is conducted by a senior assistant once every 3 months. Which he reports to the captain and takes measures to eliminate deficiencies. All this is recorded in the ship's log.
Soft patches are the main means of temporarily sealing holes; they can take the form of the hull contours anywhere on the ship. On sea vessels, four types of soft plasters are used: chainmail, lightweight, stuffed and training.
Plasters are made from waterproof canvas or other equivalent fabric; along the edge they are sheathed with lyktros (vegetable or synthetic) with four thimbles at the corners.
The sheets and guys of the chain mail patches are made from flexible steel cables, the control sheets are made from vegetable cables, and the undercut ends for all the patches are made from flexible steel cables or chains of the appropriate caliber.
The sheets and keel ends must be long enough to cover half of the ship's hull amidships and fasten on the upper deck, provided they are spaced from the vertical at an angle of 45
The control pin, designed to facilitate the installation of the patch on the hole, has, like a line, a breakdown every 0.5 m, counting from the center of the patch. The length of the control pin should be approximately equal to the length of the sheet.
Guys provided for chain mail and lightweight plasters serve as auxiliary equipment that helps the patch adhere more tightly to the hole. The length of each guy must be at least half the length of the vessel. The most durable of all soft patches is chain mail.
Plasters are applied to the hole as follows. First, using the numbering of the frames, mark the boundaries of the hole with chalk on the deck. Then the patch with the equipment is brought to the place of work. At the same time, they begin to wind the under-keel ends. At this point, the ship should not be moving. Depending on the location of the hole along the length of the vessel, the keel ends are brought in from the bow or stern and placed on both sides of the hole. If the under-keel ends are brought in from the stern, you should use weights attached to them, which will allow you to pass the under-keel end cleanly without touching the propellers and rudder.
Using staples, the heel ends are attached to the lower corners of the patch, and the sheets and control rod are attached to its upper luff. Then, on the opposite side, they begin to select the keel ends with hoists or winches, while simultaneously moving the sheets until the control rod shows that the patch has been lowered to the specified depth.
The sheets and keel ends, stretched at the required angle and selected tightly, are attached to bollards or cleats. The adherence of the patch to the damaged area is considered satisfactory if the ship's drainage systems are able to remove water from the flooded compartment.
A soft plaster allows you to quickly quickly seal cracks and small holes on ships, but it has a number of disadvantages:
Does not have the required strength;
Does not allow it to be started without the participation of a diver in cases where the hole is located near the zygomatic keel or has torn, bent outward edges;
Can be torn out of place when the ship moves.
At large sizes holes (more than 0.5 m2) as the damaged compartment is drained under the pressure of sea water, the patch will be drawn into the hole. In this case, before installing the patch, you have to resort to inserting several steel under-the-keel ends running along the hull through the hole. These ends, called false frames, are tightened on the deck with the help of turnbuckles; they play the role of a frame that prevents the patch from being pulled into the body.
Maneuvering a damaged vessel
If the ship receives any damage on the high seas, an important condition preventing his death is skillful maneuvering. As a result of damage, the ship may receive a large list, surface holes near the waterline, and as a result, as a rule, its stability decreases. Therefore, it is necessary to avoid, especially at high speed, sharp shifts of the steering wheel, which cause additional heeling moments.
If the bow is damaged, causing the hull to leak, the forward movement of the vessel will increase the flow of water, and therefore create additional pressure on the aft bulkhead of the damaged compartment. In this situation, going forward before filling the hole is risky, especially if the hole is significant. If it is impossible to repair the hole, you should significantly reduce speed or even go in reverse (for example, on multi-rotor ships).
In the event of icing of a damaged ship, its stability and maneuverability are usually further deteriorated, so the crew must take measures to combat ice.
If the damaged ship has a significant list that cannot be reduced, then the captain is obliged to maneuver so that, in order to avoid capsizing, the elevated side of the ship is not to windward, especially when the wind reaches gale force or is squally. In stormy weather, changing the speed and course relative to the wave can significantly reduce the amplitude of rolling, avoid resonance, as well as possible loss of stability in following waves, most likely at wavelengths close to the length of the vessel.
If the damage sustained by the ship during voyage is so great that ship's means the crew cannot cope with the incoming water, the smartest thing to do is to ground the ship. If possible, you should choose a shore that has a gentle slope, sandy or other similar soil without stones. It is also desirable that there are no strong currents in the landing area. In general, it is better to run aground anywhere (if this does not threaten the obvious loss of the ship) than to attempt to reach a suitable shore and expose the ship to the risk of sinking at great depths.
When deciding whether to ground a damaged ship, one must take into account the risk of reduced stability if the ship touches the ground small area bottom, especially on hard ground in an area where the depths increase sharply from the shore. The support reaction that appears at this moment, applied to the bottom of the vessel at the point of contact with the ground, is the reason for the decrease in stability. A dangerous roll may not occur if the slope of the ground is close to the angle of roll or trim of the vessel, since the ship will land on the ground immediately with a significant part of the bottom, as well as when landing on soft ground: in this case, the tip of the ship does not rest on the ground, but crashes into him.
To prevent the ship from receiving further damage from impacts on the ground in stormy weather, it must be secured aground, for example, by bringing in anchors or additional flooding of compartments.
When all the damage has been repaired, they begin to pump out water from the flooded compartments. First of all, water must be completely removed from the compartments that have the greatest width. If this recommendation is neglected, as the vessel ascends, its stability may again deteriorate due to the presence of free surfaces.
Grounding is carried out, as a rule, by the bow, but in soft ground, landing by the stern with the release of both anchors at an angle to the coastline, possibly closer to straight, is not excluded. Despite the risk of damage to the rudder complex, this method is not without advantages: the bow of the ship, which is the most durable part of the hull, will absorb the shocks of the waves, and the minimum area will be exposed to the shocks; anchors can be used to secure a vessel aground, avoiding the very labor-intensive operation of delivering them. In addition, they can be used to facilitate the subsequent refloating of the vessel.
Self-test questions:
1. What applies to emergency equipment, materials and tools?
2. Marking of emergency equipment.
3. Plasters.
4. Sheets and guys.
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 features water entering the hull are: the appearance of a static list of the vessel, a change in the nature of the pitching 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 seal 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 for 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 a 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, dropped rivets and poor tightness of seams connecting structural elements of the outer cladding can be eliminated 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 of the crack 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, with inside put wooden spacer 5 and washer 4.
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, e) cracks and holes in the bottom of the vessel: using a 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 denting, 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 outer ones.
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 the 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, wooden beams 1 and sliding stops 3 are used. The reinforcement beams are wedged, for which wedges 2 are driven 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 applied when the hole is large, when it is impossible to drain the 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. Keel ends are made of soft steel rope, and 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 - a 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, mixing it thoroughly with shovels; use Portland cement of a grade not lower than 400 (400, 500, 600) - these numbers mean the permissible load on concrete in units of 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; It is 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 for installing a 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 can have 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, vapor 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.
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 to hard to reach places of the vessel, for example, under the foundations of machinery and mechanisms, in the fore and after peaks and on the chines.
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 correctly performed baton sealing lasts a long time, is durable and often eliminates the need for immediate docking of ships.
To prepare concrete, sand, gravel, broken brick or, in extreme cases, slag are used as fillers.
The recipe and method 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 during hardening in water, the denominator - 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, install a drainage pipe, which can simply be plugged after the concrete has hardened.
Concreting damage to the bottom, 2nd bottom, and 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 embedment, 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.
