Looking at the ship in profile, you can appreciate its outlines and hull lines. The vessel itself consists of a frame, called a frame, and planking. The body kit serves to impart rigidity to the entire structure. It also shapes the appearance of the ship, its contours. You can notice that in the front (bow) part of the ship it has a special shape. The bow of the ship is specially made pointed so that when moving through the water, the ship experiences minimal resistance from the environment.
In nautical terminology, the front end of the ship is called the bow. In its location it is opposite to the stern. The bow of a ship most often has an elongated shape, narrowed from the sides. Its function is to cut waves that prevent the ship from moving quickly. This unique shape of the bow best suits the operating conditions of the ship.
Elements of the bow of the ship
The bow of the ship has a complex structure. It is designed in such a way as to reduce resistance to water elements to a minimum. At the very end of the bow there is a stem. This is a thick beam, which is a kind of continuation of the keel. In the place where the stem approaches the waterline, a metal plate is often placed, which is called a “green” or “cutwater”.
In ancient times, decorations in the form of figures - rostras - that performed a decorative function were usually placed on the bow of sailing ships. Such images made it possible not only to make the ship more attractive, but often gave warships an intimidating appearance. Roman warships, instead of decorative figures, often had massive rams at the front, which ended at the bow.
The deck elements of the front part of the ship also have their own names. The bow space of the ship's upper deck is called the "tank". On a sailing vessel, the forecastle begins at the foremast and ends at the extreme forward end of the vessel. Sometimes a ship has an elevation on the deck in the front part - a forecastle. This structural element can occupy up to half the entire length of the vessel. Rigging and mooring equipment is installed on the forward part of the deck.
In the area of the bow, the ship's hull has a reinforced structure. The set here is more durable and frequent, and the plating has significant thickness and strength. This is done so that the ship can confidently sail against the wind and strong waves. A strong bow is also needed when touching the pier during mooring. The bow, in any sailing conditions, takes on the main load of the external environment, so the requirements for its design are always more stringent.
What is the name of the sculpture on the bow of the ship?
- This is called a galleon figure (latrine) or a galleon sculpture (nose sculpture)
GALLEON FIGURES
Decoration of the bow of the ship. Figures depicting ancient gods appeared on the bow of the ship at the dawn of navigation. The sailors believed that the images of the gods would protect them from storms and storms. Over time, the galleon figures became real works of art. Wood carvers worked on them with love and diligence at the shipyards. The lion most often adorned the stems of Swedish flagships. And on the ship of the Swedish king Eric IV, a roaring lion was depicted wearing a crown.Bow decoration (galleon figure) of the 84-gun ship Chesma. 1830
The nasal end (latrine) of the Swedish galleon Vasa. 1610
The tradition of decorating the bow of a ship with a sculptural figure or relief has existed since ancient times. The ancient Egyptians often preferred sacred birds, whose image was supposed to protect the ship and its crew at sea from possible troubles. The Phoenicians usually installed a carved wooden horse's head on the bow, which symbolized the speed of their ships, and the Greeks and Romans - an angry boar or dragon, in order to intimidate a potential enemy. The dragon's head was a mandatory accessory for the Vikings' fast-moving dragons.
Bow of a French battleship
Nose figure of a Viking ship drakara (VIII-X centuries)
- Galleon or latrine figure.
From the middle of the 16th century, Spanish-Portuguese shipwrights began installing very artistic sculptures on galleons, large three-masted sailing ships adapted for transporting valuable cargo. This is where the expression galleon figure comes from. As a rule, it was an image of an angry lion standing on its hind legs. Sometimes the king of beasts was also crowned.
Outstanding sculptors were also involved in the design and creation of jewelry, as well as galleon sculptures for Russian ships in the Peter the Great era. In 1724, the sculptor Bartolomeo Rastrelli was commissioned to paint a half-length portrait of Peter I for the figurehead of the frigate Touch Me Not. Such outstanding craftsmen as N. Pimenov, M. Chizhov, M. Mikeshin, L. Klodt and others were also involved in decorating the ships.
Until the end of the 18th century, the architectural and plastic decoration of sailing ships was carried out in the Baroque style, although already in the 70s of this century a new artistic style, classicism, was established in architecture and applied arts.
According to tradition, the figure of a lion continued to be depicted on the bow for a long time, but then it was replaced by the figure of a saint, after whom the ship was named.
In the 19th century, the nose was most often decorated with an underbust or waist-length image of a female or male figure associated with the name of the ship. Aphrodite, Ceres, Venus, Urania, Diana, Juno, Bellona, Mercury, Arsie, Pallas, Pollux, Castor, Argus, Hector, Melpomene, Proserpina and others, they were all not only figureheads, but also the names of the ships on which they were installed . - ROSTR Latin. rostrum - beak, protruding part, bow of a ship..)))))))
Let's consider main elements of the vessel. A small vessel, like any transport vessel, consists of a hull (the vessel itself) and a superstructure or deckhouse. The hull of the ship is the main part, which includes the frame and plating. The set consists of longitudinal and transverse links that serve as the basis for the plating - the shell of the vessel, which provides the hull with water resistance and, together with the set, strength and rigidity. The outlines of the hull are usually smooth, with sharp points characteristic only of the bow and stern. The front end of the vessel is called the bow, and the rear end is called the stern; the sides, or walls of the hull - the right and left sides, when viewed from the stern. The part of the hull that is under water is called underwater, and above the water is called surface, the lower part of the hull is called the bottom, and the upper, horizontal part is called the deck. Small vessels, such as motorboats, may not have a deck.
Superstructure is a structure above the hull of a ship, which is a continuation of its sides, or a room located on the deck along the entire width of the ship (hull). A high and developed superstructure not only impairs the stability of the vessel, but also increases its windage - the effect of wind on the vessel.
The deckhouse is a separate part of the superstructure or structure on the deck, which does not occupy the entire width of the ship's hull (there are passages on the deck along the sides). On small vessels, the pilothouse is often referred to as the room for controlling the vessel and engine. Only large boats and motor yachts have superstructures and separate deckhouses. On most powerboats, the superstructure and deckhouse are combined.
The bulwark is a lightweight structure - a continuation of the side above the deck in the bow and middle parts of the vessel. At the aft end, the bulwark is called a tailrail. The bulwark can be temporary (wooden or canvas), raised during rough seas, when passing rapids, sailing, etc.
Cockpit - a cutout or recess in the deck to accommodate people.
The engine well is a watertight structure at the transom of the vessel, forming a recess in the hull of the vessel and designed to accommodate an outboard motor and provide the required freeboard height.
A ship's hull set (see figure) is a structural design consisting of longitudinal and transverse links: keel, stem, sternpost.
The main structural elements of the hull of a vessel - boat
1 - deck flooring; 2 - beam; 3 - carlings; 4 - cockpit trim; 5 - slan; 6 - cockpit coaming;
7 - aft bulkhead; 8 - transom; 9 - motor niche; 10 - stem; 11 - keel;
12 - side (outer) plating; 13 - gunwale; 14 - zygomatic stringer; 15 - deck stringer; 16 - half beam; 17 - zygomatic book; 18 - side stringer.
The keel is the main longitudinal connection running along the entire length of the vessel from stem to sternpost in the form of a beam. The keel is an element that ensures the strength of the vessel.
The stem is a forward structural design (a continuation of the keel). This completes the set of the ship's hull from the bow. In small motor vessels, the stem is usually inclined, smoothly turning into the keel.
Sternpost - structural design of the stern end of the vessel (continuation of the keel). This ends the set. The sternpost can consist of two parts: the front one - the steering post, through which the propeller shaft passes, and the rear one - the rudder post, onto which the rudder is hung. On motorboats, there is a transom board (transom) at the stern.
Stringers are internal longitudinal connections for fastening the skin. They are divided into side and bottom - keelsons.
Carlings are longitudinal under-deck connections.
Frames are transverse side braces of the hull. The distance between two frames is called spacing. In a theoretical drawing, booms are the contours of the cross-section of a ship.
Beams are transverse under-deck connections of the deck. The hull of a small boat can be divided by transverse bulkheads, which are made watertight. Bulkheads extend to the deck or are of varying heights. The outermost bow part of the vessel between the stem and the first bow bulkhead is called the forepeak, the outermost aft compartment is the afterpeak.
Fender beam:
A longitudinal beam on the inside of the side of a wooden boat at the height of the waterline, and more often above it, connecting the upper ends of the frames of one side;
A wooden or metal beam installed outside the side to protect the ship from damage during impacts during mooring.
Gunwale - a flat beam covering the edge of the skin and the ends of the frames.
The shoulder is a longitudinal wooden rail on the outside of the sides, which acts as an external fender that serves to protect the sides from damage.
Coaming is a structure bordering a cutout in the deck to protect hatches and cockpits from being overwhelmed by water.
Slan, or payol - boards made of boards that are laid on the frames to protect them and the sheathing.
In addition to the hull, the small vessel has a number of devices: steering, mooring, anchor etc.
Warship- a complex self-propelled engineering structure, bearing the naval flag of its state assigned to it and staffed by a military crew. Equipped with modern equipment, mechanisms and weapons and designed to perform tasks typical of its class. Every ship must have certain seaworthiness, survivability and have a minimum weight (displacement) with sufficient strength and the required weapons. The basis of any ship is the hull.Surface ship hull(Fig. 1.1) - a steel, waterproof, hollow inside body with a streamlined shape. It provides the creation of buoyancy force and is a platform on which various weapons and equipment are mounted, depending on the purpose of the ship. The hull is equipped with steering, anchor, mooring, towing, lifting and other devices. Inside the hull are located: main and auxiliary mechanisms, living and service premises, ammunition cellars, storage of fuel, oils, water, chain boxes for cleaning anchor chains and other internal devices. Superstructures are installed on the upper deck of the hull, masts, pipes and other structures and mechanisms are installed.
Rice. 1.1. Location of the main hull structures, placement of weapons, posts and premises on a surface ship:
A - tank; B - waist; V - yut; 1 - guy rod; 2 - upper deck; 3 - bow anchor device; 4 - breakwater; 5 - bow artillery mount; 6 - anti-submarine weapons; 7 - bow (running) bridge; 5 - artillery fire control post; 9 - mast; 10 - chimney; 11 - torpedo tube; 12 - aft bridge; 13 - aft artillery mount; 14 - aft spire; 15 - flagpole; 16 - valance; 17 - platform; 18 - personnel quarters (aft); 19-stern ammunition magazine; 20-compartment of auxiliary mechanisms; 21 - engine room; 22 - watertight bulkheads; 23 - boiler room; 24 - second bottom; 25 - officers' living quarters; 26 - personnel quarters (bow); 27 - bow ammunition magazines; 28 - spire compartment; 29 - chain box
Structurally, the hull of a surface ship consists of the following main parts: frame (frame), side and bottom plating, decks and platforms, internal bottom, longitudinal and transverse watertight bulkheads. Framing and plating are essential elements of any hull; the presence of decks and bulkheads depends on the purpose of the ship.
Rice. 1.2. Ship hull system:
1 - beams of the main direction; 2 - cross beams
Case set- a system of rigidly interconnected longitudinal and transverse beams of various designs, connected by welding or riveting to sheets of outer cladding, second bottom and decks. In most cases, the resulting floors are reinforced by a set of whole (uncut) beams, called main direction beams, and split beams perpendicular to them, called cross beams (Fig. 1.2).
Depending on the direction of the main beams relative to the ship, three framing systems are distinguished: transverse, longitudinal and mixed. In the transverse hull framing system, the main direction beams run across the ship, are structurally continuous along its width and consist of frames along the sides, transverse beams along the decks and floors along the bottom. With a transverse framing system, longitudinal beams (vertical keel, stringers) are also required, but the latter are cross-links, their number is small (3-5). This dialing system is widely used on river and small sea vessels (tugs, barges).
In the longitudinal framing system, the main (continuous) beams run along the ship and consist of a significant number of stringers running continuously along the bottom and sides, longitudinal beams along the decks and a large number of simple longitudinal beams located along the bottom, the second bottom, sides and upper deck (between the stringers and longitudinal beams). The frames are made in the form of powerful frames, spaced 1.5-2.5 m apart from each other and cut at the intersections with longitudinal braces. This recruitment system in its pure form is currently used only on oil tankers that do not have a second bottom.
Modern warships are built mainly using a mixed construction system (Fig. 1.3): the construction of the bottom, second bottom and decks is made longitudinal; the set of sides and ends of the ship is transverse.
Rice. 1.3. Mixed recruitment system ship hull:
1 - deck belt; 2 - longitudinal beam; 3 - deck stringer; 4 - beam book; 5- frame; 6 - shearstrek; 7 - beam; 8 - side belts; 9-side stringer; 10 - zygomatic book; 11- flora; 12-bottom stringer; 13 - zygomatic girdle; 14 - bottom belt; 15 - tongue and groove belt; 16 - keel belt; 17 - vertical keel; 18 - second bottom flooring; 19 - longitudinal watertight bulkhead
Regardless of the framing system, the hull must have strong connections in all three directions (longitudinal, transverse and vertical) in order to reliably withstand the forces acting on the ship. Depending on the purpose and location of the hull parts, a set of bottoms, a set of sides, a set of decks, etc. are distinguished.
Bottom set- an overlap consisting of mutually intersecting longitudinal and transverse connections, called stringers and floras, respectively. In the middle of the frame, coinciding with the center plane of the ship, a vertical keel is installed - the main longitudinal connection of the bottom frame, which absorbs the forces that arise during the longitudinal bending of the ship.
Rice. 1.4. Design of vertical keels:
a, b - destroyers; c - cruisers; g - keel beam of a large ship
The keel runs along the entire length of the ship. The design of the keels depends on the class of ships. In Fig. Figure 1.4 shows the design of keels for some ships. Previously, on large ships, the vertical keel was sometimes replaced by two stringers, which formed a keel beam. On ships built in recent years, the keel beam is usually replaced by a vertical keel with reinforced linings, plating and internal bottom (Fig. 1.5). At the bow and stern ends of the ship, the keel is connected to the stem and sternpost. Sometimes a horizontal sheet is installed above the vertical keel, called a horizontal keel.
Rice. 1.5. Welded keel structure of a large ship
Bottom stringers are longitudinal beams that run parallel to the keel and together with it provide the longitudinal strength of the hull. By design, stringers are riveted or welded beams of various sections. The number of stringers on each side depends on the size of the ship. Approximately, there are 3 stringers on destroyers, and 4-5 on cruisers. Toward the bow and stern, the number of stringers decreases, as the width of the bottom of the ship decreases. When the bottom passes into the side of the ship, one stringer is placed on board; such stringers are called bilge stringers.
Flours are vertical steel sheets that are welded to the vertical keel, run across the ship and form part of the frame frame. They are impenetrable and permeable. The first ones are installed to delimit the double bottom compartments and ensure the watertightness of the compartments. The latter have oval cutouts to facilitate the design, provide passage and lay pipes in the double-bottom compartments.
Lateral keels (Fig. 1.6) are made to reduce the span of the ship during lateral rolling and partially serve as a longitudinal link. The width of the side keels does not exceed the dimensions of the hull. Their design can be varied.
Rice. 1.6. Side keels:
a - location of the keel; b, c - keel designs
Board set- continuation of the bottom set; consists of side stringers and frames.
The side stringers are laid along the entire length of the ship, from bow to stern, and are strong beams with stiffening ribs. They connect the side branches of the frames, absorb the load from them and transfer it to the transverse bulkheads. Sometimes additional stiffeners are installed between the stringers.
Frames are the transverse ribs of the ship's hull, connected to the decks, bilge stringers and bottom floors. They can be cut on each deck or pass through decks without being cut. The connection of the frames with the transverse beams of the deck set is carried out using brackets. The structural design of frames can be varied: from angles and sheet strips to riveted and I-beams, and, finally, trusses (frame frames). The space between adjacent frames is called spacing. In our military shipbuilding, we have adopted a system of numbering frames from bow to stern; The stem is taken as zero. The middle frame along the length of the ship is conventionally called the midship frame (midship).
Deck set- a system of intersecting transverse and longitudinal beams. The main direction beams are longitudinal beams. They are end-to-end, cut into transverse beams and are attached to them with brackets. Transverse beams and half beams are located from one another at a distance equal to the spacing, and are attached to the frames with brackets. To communicate with the rooms located below the decks, holes (hatches) are cut in the latter, which are bordered along the perimeter above the deck by vertical waterproof sheets called coamings (Fig. 1.7). Below the decks, longitudinal beams are placed that support the transverse beams of the decks, which are called karlengs.
Rice. 1.7. Layout of carlengs and coamings:
1 - deck sheet; 2 - coaming; 3 - carlengs; 4 ~ cross beams
Hatches come in round and rectangular shapes. Each hatch cover has a seal and a rubber rim to ensure water resistance. According to their purpose, hatches are divided into entrance, cargo and light. The movement of personnel through hatches is carried out along ladders (light-weight ladders). Stairways serve for communication between decks; There are inclined and vertical ones. Inclined ladders, as a rule, have handrails made of metal pipes; vertical - installed in mines, emergency gatherings (emergency, spare), at exits from machine and boiler rooms, ammunition cellars, etc.
Shafts (Fig. 1.8) are pipes of a special design (usually quadrangular cross-section) passing through the inter-deck spaces. On the upper (lower) deck, the shaft has a neck with a waterproof lid on wings or rivets.
Rice. 1.8. Waterproof shaft
When heavy local cargo is located on the deck - gun mounts, masts, deck mechanisms, etc. - under them in the inter-deck spaces, pillars are installed (Fig. 1.9), which are calculated for the weight of the decks with the set and cargo located on the decks. Pillers come in different designs: permanent and removable.
Rice. 1.9. Welded tubular pillers
Set at the ends of the ship. Transverse rigidity is given to the ends of the ship by frames, floors and beams, which work together with deck flooring and side plating, as well as transverse bulkheads, which are placed (like frames) at the ends more often than in the middle part of the ship. To give strength to the converging edges of the side and bottom plating sheets along with the set and to create a rigid structure for the ends of the ship, stems are installed. At the bow end of the ship there is a shape, which is made in the form of a forging, casting or welded structure. It is able to withstand impacts from waves, ice and floating objects. The aft end of the ship ends with a cast part - axtershtev - nem. The shape and design of the stems depend on the purpose and size of the ship, the number of propellers, the type of rudder, etc.
Ship shell consists of outer plating (bottom and side) and deck flooring.
The outer skin is a waterproof shell that separates the internal volume of the ship from the water and simultaneously serves to ensure the longitudinal and lateral strength of the ship. It consists of a number of belts made up of separate sheets and located along the ship. The connection of two sheets of one belt forms a joint; the connection of the belts is the groove of the outer skin. Sheathing sheets are connected in various ways: end-to-end, edge-to-edge (herringbone), smooth, on planks, etc. Depending on the location of the outer skin belt they are called: tongue-and-groove, bottom, zygomatic, side, ice shearstrake (Fig. 1.10) Typically, the tongue-and-groove belt (adjacent to the keel) and shearstrake (sheathing belt on the beams of the upper continuous deck) are made thicker than the other belts to increase the overall longitudinal strength of the ship. On warships, in addition, the skin is often doubled along the keel path, waterline (ice belt), under the anchor fairleads, and in the area of the propellers.
Rice. 1.10. Location of outer cladding belts:
1 - shearstrek; 2 - ice; 3 - side; 4 - zygomatic; 5 - bottom; 6 - tongue and groove; 7 - keel
The deck limits the internal volume of the ship from above and consists of sheets resting on the deck set. Deck flooring is made from sheets of maximum length, which are placed with the long side along the ship. The outermost sheet of deck flooring, running parallel to the side contour, is called a deck stringer and serves to ensure the longitudinal strength of the ship. Throughout the entire length of the deck, with the exception of the area at the ends of the ship, it has a thickness that is 20-30% greater than the adjacent deck flooring belts. The usual thickness of the belts adjacent to the deck stringer: for small ships - 4; destroyers - 5; cruisers - 7-8 mm. The minimum deck thickness is determined by durability conditions, but must be at least 4 mm. The totality of the sheets and set is the deck itself.
The ship's hull is divided in height into a number of decks and platforms to accommodate equipment, weapons, cargo and personnel, as well as to ensure unsinkability, fire safety and strength. Based on their location on the ship, the decks are called upper, middle and lower (Fig. 1.11).
Rice. 1.11. Ship decks:
1 - outer bottom; 2 - second, or inner, bottom; 3 - third bottom; 4 - second platform; 5 - first platform; 5 - lower deck; 7 - middle deck; 8 - upper deck; 9 - forecastle deck; 10 - superstructure deck
The platforms run under the lower deck at the ends of the ship and do not run along the entire length of the ship, but are interrupted and in this way differ from decks. The platforms are counted from top to bottom. The number of decks and platforms depends on the design, purpose and size of the ship.
Upper deck(main) is a kind of roof and withstands the greatest tensile and compressive stresses during longitudinal bending of the hull, stress from lateral compression of the hull, local pressure of cargo, powder gases during a shot and water on the deck. To reduce flooding with water during waves and thereby improve the seaworthiness of the ship, the deck usually has sheer, i.e., a rise from the middle part to the bow and stern (Fig. 1.12). In the transverse direction, the upper deck has a deflection, i.e., a convexity, which ensures water flow to the sides and increases the longitudinal rigidity of the deck. Directly on the upper deck, as well as on special foundations and foundations, superstructures of various purposes and types, deckhouses, bridges, weapons, deck devices, ship control posts and other equipment are placed, masts and chimneys are installed.
Rice. 1.12. Scheme of sheer and deck deflection:
a - grayness; b, c, d - deflection at various sections along the length of the ship
The upper deck is conventionally divided into sections called: b a k - the section of the upper deck from the stem to the foremast or conning tower; sh k a f u t - from the foremast or conning tower to the mainmast or stern superstructures inclusive; poop - from the mainmast or stern superstructures to the stern section. Some warships and many auxiliary vessels have additional decks: above the forecastle - a forecastle; waist - spardek; yutom - poop.
On the upper deck, along the sides, a waterway (gutter) and a scupper system are installed to remove water from the deck, superstructures and platforms. To ensure that the deck is less flooded with water, wave deflectors (breakwaters) and canopies are installed on the forecastle (forecastle).
Deck superstructures- parts of the ship's hull, located on some part of the upper deck along the entire width of the ship and forming closed volumes on it, intended for use as residential and various service premises. In accordance with the division of the upper deck into sections of the superstructure located on it, they are called bow (tank), middle and stern (poop). The bow superstructure (forecastle) also serves to increase the height of the bow of the ship's hull.
Typically, rooms located above the upper deck do not reach the side. Therefore, superstructures are conventionally called those that are located over a relatively large length of the ship, and deckhouses are short superstructures. R o s t r y - open superstructure; They are a lattice (sometimes solid) flooring, built above the upper deck and resting on the inner side on the middle superstructure, and on the outer side on the pillars. The flooring is laid on roaster beams. Rostras are intended to accommodate boats, lifeboats, life-saving equipment and automatic anti-aircraft artillery.
Decks and platforms of internal premises are supported by beams and are calculated on their own weight and the weight of cargo located on them. The best covering for interior decks is linoleum, which is easy to clean, gives the premises a neat appearance, and has sound and heat insulating qualities. The decks of the living quarters, located above rooms with high temperatures (engine and boiler rooms), are covered with heat-insulating boards made of various insulating materials.
Rice. 1.13. Bottom set design diagram:
1, 2, 16, 17 - platform sections; 3-15 - sections of the internal bottom
Inner bottom- steel decking going on top of the bottom set (Fig. 1.13). Along its length, it covers the area of recruitment of a longitudinal or mixed system. In the bow and stern, where the set is most often transverse, there is no second bottom; it is being replaced by platforms. To avoid rapid destruction by corrosion, the thickness of the inner bottom sheets is taken from 4 to 10 mm, depending on the class of the ship. In engine and boiler rooms the flooring is thicker. The double-bottom space is divided by floras and stringers into waterproof compartments (cages) with manholes (necks) closed with waterproof lids (Fig. 1.14). The space between the outer bottom skin and the second bottom (interbottom space) is used to store fuel, oil, fresh water and ballast water.
Rice. 1.14. Waterproof neck cap with wings
Bulkheads- flat vertical structures (walls), consisting of sheets and a set; are made waterproof and permeable. Transverse watertight bulkheads, dividing the internal volume of the ship along the length, form autonomous watertight compartments. Longitudinal watertight bulkheads form watertight side compartments. Watertight bulkheads prevent the spread of water entering through holes throughout the ship, thereby ensuring its unsinkability, and also prevent the spread of fire and toxic substances.
The transverse watertight bulkheads that separate the ship from the bottom to the upper deck are called the main ones. Semi-bulkheads, like main bulkheads, carry vertical and horizontal loads, but unlike them they do not go from side to side. Between the main bulkheads, secondary (permeable) bulkheads are installed to separate the interior spaces.
Watertight doors (Fig. 1.15) are placed on watertight bulkheads and serve as access to watertight compartments. Such a door consists of a stamped metal sheet with a device for fastening sealing rubber around its perimeter and six wedge latches with individual or prizodny central latching. Lightweight doors that lead to the superstructure and bridge rooms have a lightweight design. They are also equipped with rubber gaskets that protect against the penetration of water (splashes) and light (from the room).
Rice. 1.15. Waterproof door
Forward
Table of contents
Modern ships are made from materials whose density is many times higher than the density of water. But they do not sink because they are designed in such a way that they have many rooms filled with air inside.
When talking about a ship, we use the terms " ship " or " vessel ". Meanwhile, these concepts do not mean the same thing. In general, a ship is considered to be any vehicle that is used to transport passengers and goods by water. Different rules and codes interpret this concept differently. For example, in the International Rules to prevent collisions between ships at sea, it is written that a ship is any means of transportation on water. Therefore, a ship is a broader concept. And ships are generally considered to be large sea vessels and ships of any size that fly a naval flag. Each ship has its own unique the name flies under the flag of the state in which it is officially registered.
How the ship works
1 – bow, 2 – bulb, 3 – anchor, 4 – side, 5 – stern, 6 – stern, 7 – chimney, 8 – wheelhouse, 9 – deck.
The ship's hull consists of several parts.
The front part is called nose . As it moves, it cuts the waves and is therefore shaped in such a way that water resistance is minimal. The anterior tip of the nose is called stem . And the part of the nose protruding below the waterline is called bulb . It changes the direction of water flow through the hull, thereby reducing drag, increasing the speed of the ship and reducing fuel consumption.
The back of the ship is called stern It is divided into surface And underwater parts. In the underwater part there are steering wheel And propeller screw . On the surface there is an engine room and a cargo compartment.
The side part is called board . Bulwark - This is the part of the side located above the deck.
The interior space of the ship is divided vertically into rooms by a horizontal ceiling - deck. There can be several decks: upper deck, wheelhouse deck, superstructure deck, forecastle deck, first, second deck, etc. It all depends on the size and purpose of the ship. For example, lifeboats are located on the boat deck. Passenger ships have special promenade decks.
Along the bottom of the vessel, from bow to stern, there is a longitudinal beam called keel . It ensures the strength of the hull and bottom.
The line of contact of the hull with the calm surface of the water is called waterline . It conditionally separates the surface and underwater parts of the ship.
In order to stay in one place, the vessel must be thrown onto the ground when parked. anchor .
Marine engine sets in motion ship propulsors : air and propeller, paddle wheel). On sailing ships, the propellers are the sails. (Propulsors are devices that convert engine energy or any other energy, such as wind energy, into work to move a vehicle.)
The vessel's water resistance, buoyancy and unsinkability are ensured by frame . It consists of a casing and a set.
Center of mass and center of pressure of the ship
When a ship floats, it is acted upon by two forces, equal in magnitude and opposite in direction: gravity (weight) R and buoyant force.
Ship weight R - this is the sum of the weights of the hull, mechanisms, fuel, water reserves, crew, weapons, etc. The force of gravity is always directed downward and pulls the ship to the bottom. It is applied to a point called the ship's center of gravity, or mass center of gravity . When designing and building a ship, they try to ensure that its center of gravity is at center plane . This is a vertical plane that runs through the entire length of the vessel and divides it into 2 symmetrical parts. The center of gravity is located either at half the height of the freeboard or slightly below it.
The buoyant force is applied to the geometric center of gravity of the immersed volume of the ship and is directed vertically upward. The point of application of the buoyant force is called pressure point , or center of pressure .
When a ship is created, they make sure that both of these centers (the ship’s center of gravity and the center of pressure) are in the center plane on the same vertical.
Equilibrium equation for a ship has the form:
P = γ (V o −V n) , or:
P = γV
Where
V n - waterproof volume of the ship above the waterline,
V o – the entire waterproof volume,
P - weight of the vessel,
γ - density of water,
V - immersed volume
This equation is called basic buoyancy equation.
Buoyancy reserve
Buoyancy is the most important seaworthiness of a ship. This is the ability to stay afloat along with the cargo necessary to perform certain tasks. Having lost buoyancy, the ship will sink.
Each ship has buoyancy reserve , which is defined as the percentage of all watertight volumes of a ship located above the waterline to its total watertight volume.
W = V n / V o * 100
From a physics point of view The buoyancy reserve is equal to the volume of water that the ship can take on board while remaining afloat.
For example, if the reserve of buoyancy is 50%, then the ship is immersed in water such that its watertight volume above the waterline is equal to the volume below it.
The volume of superstructures and all protruding parts on the upper watertight deck is not included in the buoyancy reserve. The volumes of damaged compartments are also excluded from it.
If a ship takes on board an amount of water equal to its buoyancy reserve, it will sink into the water up to the main deck. Its reserve of buoyancy in this case will become equal to zero. And the ship itself will be in an unstable position. In physics this is called neutral buoyancy. Even a small impact on a ship in this state can cause the buoyancy to become negative and the ship to sink. Therefore h In order for navigation to be safe, it is established for any ship mandatory reserve buoyancy . It is designated cargo waterline or load line – a special mark applied to the vessel. It shows the level to which the ship can be loaded. The larger the load, the closer the load line is to the water.
To preserve the buoyancy reserve, the ship's hull and all its premises are made waterproof. They are separated by bulkheads and decks. Doors, portholes, and hatches are waterproof. If water enters any room on the ship, it will not be able to penetrate into other rooms. It is very important that all these ship structures are always in good condition.