TACTICAL AND TECHNICAL DATA OF VARIOUS TYPES OF MISSIONS AND MISSION WEAPONS.

TACTICAL AND TECHNICAL DATA OF VARIOUS TYPES OF MISSIONS AND MISSION WEAPONS.

TACTICAL AND TECHNICAL DATA OF VARIOUS TYPES OF MISSIONS AND MISSION WEAPONS. UNITED KINGDOM There is almost no published data on the development of rockets and rockets in the UK. However, it must be admitted that not much has been done. It is officially reported that all developments

TACTICAL AND TECHNICAL DATA OF VARIOUS TYPES OF MISSIONS AND MISSION WEAPONS.

TACTICAL AND TECHNICAL DATA AND TABLES OF ROCKET LAUNCHES

TACTICAL AND TECHNICAL CHARACTERISTICS OF HEAVY TANKS Self-propelled launcher SM-SP21 of the RT-20P missile based on the chassis of the T-10 heavy tank Self-propelled launcher SM-SP21 of the "Gnome" missile based on the chassis of the T-10 T-10 heavy tank in the Museum of Military Glory, Saratov T-10A at the military

Table 1 Tactical and technical characteristics of assault rifles, carbines and light machine guns for the "intermediate" cartridge Name Fedorov assault rifle mod. 1916 AK AKS SKS AKM AKMS RPK RPKS Caliber (mm) 6.5 7.62 7.62 7.62 7.62 7.62 7.62 Weight (kg) 4.4 4.86 4.86 3.9 3.6 3 , 8 5.6 5.9 Overall length

Table 2 Tactical and technical characteristics of assault rifles and light machine guns for "low-impulse" cartridge Name AK-74 AKS-74 AKS-74U RPK-74 RPKS-74 AK-74M RPK-74M Caliber, mm 5.45 5.45 5.45 5.45 5.45 5 , 45 5.45 Weight, kg 3.6 3.67 3.0 5.46 5.61 3.6 5.46 Overall length, mm 940 940 730 1060 1060 940 1065 Length with folded.

Table 3 Tactical and technical characteristics of machines for "low-impulse" cartridge Name AK101 AK102 AK103 AK-104 AK-105 AKK-971 AN-94 A-91 A-91 A-91 Caliber, mm 5.56 5.56 7.62 7.62 5.45 5 , 45 5.45 5.45 5.56 7.62 Weight, kg 3.8 3.6 3.8 3.6 3.5 3.3 4.3 1.75 1.75 1 * 75 Overall length, mm 943 824 943 824 824 965 943 604 604 604 Length with folded

Table 4 Tactical and technical characteristics of machines for special cartridges Name APS 9 А-91 ВСК-94 ВСС АС СР-3 "Whirlwind" Caliber, mm 5.66 9 9 9 9 9 Weight, kg 2.46 2.55 3.34 3.41 2.96 2.0 Overall length, mm 823 604 900 894 875 640 Length with folded butt, mm 615 384 - - 615 396 Barrel length,

Table 5 Tactical and technical characteristics of weapons Baryshev AB -5.45 AV-7.62 AVK KPB AR GB Weight, kg 3.4 3.6 4.7 13.2 15.3 Overall length, mm 865 960 1000 1455 950 Length with folded stock, mm 645 710 750 1215 700 Barrel length, mm 415 415 500 750 300 Bullet muzzle velocity, m / s 900 715 800 840 185 Rate of fire,

The performance characteristics of the KM2K knife Total length - 305 mm Total length with scabbard - 327 mm Blade length - 172 mm Blade width - 30 mm Blade thickness - 4.6 mm Scabbard dimensions: length x width - 196 x 30 mm Knife weight - 303 g Knife weight with scabbard - 516 g Blade material -

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1. Introduction

2. Performance characteristics

2.1 Main dimensions of the vessel

2.2 Displacement

2.3 Carrying capacity

2.4 Capacity

2.5 Ship speed

3. Seaworthiness

3.1 Buoyancy

3.2 Stability

3.3 Stroke

3.4 Controllability

3.6 Unsinkable

4. Sources

Introduction

The ship is a complex engineering and technical floating structure for the carriage of goods and passengers, water industry, mining, sports, as well as for military purposes.

In the Law of the Sea, a seagoing vessel is understood as a self-propelled or non-self-propelled floating structure, that is, an object artificially created by man, intended for permanent stay at sea in a floating state. For the recognition of a structure as a ship, it does not matter whether it is equipped with its own engine, whether the crew is on it, it is moving or is mainly in a stationary floating state. The same definition, apart from the sea, applies to inland water bodies and rivers.

As an engineering structure intended for specific purposes, the vessel has operational and seaworthy characteristics.

Performance characteristics

Main dimensions of the vessel

The main dimensions of the vessel are called its linear dimensions: length, width, depth and draft.

Diametral plane (DP) - vertical longitudinal plane of symmetry of the theoretical surface of the ship's hull.

The plane of the midship frame is a vertical transverse plane passing in the middle of the ship's length, on the basis of which the theoretical drawing is built.

Under the frame (Шп) is understood in the theoretical drawing the theoretical line, and in the design drawings - the practical frame.

Constructive waterline (KVL) - the waterline corresponding to the estimated total displacement of the vessels.

Waterline (VL) - the line of intersection of the theoretical surface of the hull with a horizontal plane.

Aft perpendicular (CP) - the line of intersection of the diametrical plane with the vertical transverse plane passing through the point of intersection of the stock axis with the plane of the structural waterline; CP on the theoretical drawing coincides with the 20th theoretical frame.

The nasal perpendicular (NP) is the line of intersection of the diametral plane with the vertical transverse plane passing through the extreme nasal point of the structural waterline.

Main plane - the horizontal plane passing through the lowest point of the theoretical surface of the body without protruding parts.

In drawings, descriptions, etc., dimensions are given for length, width and height.

The length of the vessels is determined parallel to the main plane.

Maximum length L nb - the distance measured in the horizontal plane between the extreme points of the bow and stern ends of the hull without protruding parts.

Length along the constructive waterline L kvl - the distance measured in the plane of the constructive waterline between the points of intersection of its bow and stern with the diametrical plane.

Length between perpendiculars L PP - the distance measured in the plane of the structural waterline between the fore and aft perpendiculars.

Length at any waterline L ow is measured as L sql

Length of the cylindrical insert L c - the length of the ship's hull with a constant section of the frame.

The length of the nasal cusp L n - is measured from the nasal perpendicular to the beginning of the cylindrical insert or to the bulkhead of the largest section (for ships without a cylindrical insert).

The length of the stern edge L k - is measured from the end of the cylindrical insert or frame of the largest section - the end of the stern part of the waterline or other designated point, for example, the stern perpendicular. Breadth measurements of vessels are measured parallel to the main and perpendicular to the centerline.

Maximum width B nb - the distance measured between the extreme points of the body, excluding protruding parts.

Width at the midship frame B is the distance measured at the midship frame between the theoretical surfaces of the sides at the level of the design or design waterline.

Width at design waterline V kvl - the largest distance measured between the theoretical surfaces of the sides at the level of the structural waterline.

Width over VL V vl is measured as V sq.

Height dimensions are measured perpendicular to the base plane.

Depth H is the vertical distance measured on the midship frame from the horizontal plane passing through the point of intersection of the keel line with the plane of the midship frame to the side line of the upper deck.

Height of the side to the main deck Н Г П - the height of the side to the uppermost continuous deck.

Depth to twin deck H TV - depth to deck below the main deck. If there are several twin decks, then they are called the second, third, etc. deck, counting from the main deck.

Draft (T) - vertical distance measured in the plane of the midship frame from the main plane of the structural or design waterline.

Draft bow and stern draft Т n and Т к - are measured on the bow and stern perpendiculars to any waterline.

Average draft T avg - measured from the main plane to the waterline in the middle of the ship's length.

Fore and aft sheerness h n and h k - smooth rise of the deck from the midsection to the bow and stern; the amount of lift is measured at the fore and aft perpendiculars.

Kill beams h b - the difference in height between the edge and the middle of the deck, measured at the widest point of the deck.

Freeboard F is the vertical distance measured at the side of the ship midway from the top of the deck line to the top of the corresponding load line.

If necessary, other dimensions are indicated, such as, for example, the highest (overall) height of the vessel (height of a fixed point) from the load waterline during an unladen voyage for passage under bridges. Usually, however, they are limited to indicating the length - the largest and between the perpendiculars, the width at the mid-frame, the side height and the draft. In cases of application of international Conventions - on the safety of life at sea, on load lines, measurement, classification and construction of ships - they are guided by the definitions and dimensions established in these Conventions or Rules.

Displacement

Displacement is one of the main characteristics of the vessel, which indirectly characterizes its size.

The following displacement values ​​are distinguished:

Mass or weight and volume,

Surface and underwater (for submarines and submarines),

· Light displacement, standard, normal, full and maximum.

The full displacement is equal to the sum of the empty displacement and the deadweight.

Displacement of a vessel - the amount of water displaced by the underwater part of the vessel's hull. The mass of this amount of water is equal to the weight of the entire vessel, regardless of its size, material and shape. (According to Archimedes' law)

Ш Mass (weight) displacement is the mass of a ship afloat, measured in tons, equal to the mass of water displaced by the ship.

Since during operation the mass of the vessel can vary widely, in practice two concepts are used:

Displacement in full load D, equal to the total mass of the ship's hull, all mechanisms, devices, cargo, crew passengers and ship's stores at the highest permissible draft;

Empty displacement D0, equal to the mass of the vessel with equipment, permanent spare parts and supplies, with water in boilers, machinery and pipelines, but without cargo, passengers, crew and without fuel and other supplies.

W Volumetric displacement - the volume of the underwater part of the vessel below the waterline. With a constant weight displacement, the volumetric displacement changes depending on the density of the water.

That is, the volume of the liquid displaced by the body is called the volumetric displacement.

The center of gravity of the volumetric displacement W is called the center of displacement.

Standard displacement - the displacement of a fully equipped ship (vessel) with a crew, but without supplies of fuel, lubricants and drinking water in the tanks.

Normal displacement is a displacement equal to the standard displacement plus half of the fuel, lubricants and drinking water in the tanks.

Full displacement (loaded displacement, full load displacement, designated displacement) - a displacement equal to the standard displacement plus full reserves of fuel, lubricants, drinking water in tanks, cargo.

Displacement reserve is an excess addition to the ship's mass taken during design to compensate for the possible excess of the mass of its structure during construction.

The largest displacement is a displacement equal to the standard displacement plus the maximum reserves of fuel, lubricants, drinking water in tanks, cargo.

Submarine displacement - the displacement of a submarine (bathyscaphe) and other submarines in a submerged position. Exceeds surface displacement by the mass of water taken when immersed in the main ballast tanks.

Surface displacement - the displacement of a submarine (bathyscaphe) and other submarines in a position on the surface of the water before submersion or after surfacing.

Carrying capacity

Carrying capacity is one of the most important operational characteristics - the mass of cargo for the transportation of which the vessel is designed - the weight of various types of cargo that the vessel can carry, provided that the design landing is maintained. Measured in tons. There is a net payload and deadweight.

Net Payload (Payload) is the total mass of the payload transported by the ship, i.e. weight of cargo in holds and weight of passengers with luggage and fresh water and provisions intended for them, weight of caught fish, etc., when loading the vessel according to the design draft.

Deadweight (full load) - DWT - deadweight tonnes. It is the total mass of the payload transported by the ship, constituting the net carrying capacity, as well as the mass of fuel, water, oil, crew with luggage, provisions and fresh water for the crew when the ship is loaded at the design draft. If a loaded vessel takes on liquid ballast, then the mass of this ballast is included in the vessel's deadweight. Deadweight at summer load line draft in sea water is an indicator of the size of a cargo ship and its main operational characteristic.

The carrying capacity should not be confused with the cargo capacity, and even more so with the registered capacity (registered cargo capacity) of the vessel - these are different parameters measured in different quantities and having different dimensions.

Capacity

In addition to determining the carrying capacity of a vessel in weight units (now usually in metric tons) and measuring the total weight of a vessel by a displacement parameter, there is a historical tradition of measuring the internal volume of a vessel. This parameter is only used for civilian ships.

The capacity of the ship is the volumetric characteristic of the premises of the ship. Cargo capacity and registered tonnage should not be confused. There is also a “passenger capacity” parameter for passenger and cargo-passenger ships.

The parameters of capacity (cargo capacity), carrying capacity (including deadweight) and displacement are not related to each other and, in the general case, are independent (although for one class of ships there are coefficients that indirectly relate one parameter to another).

Gross tonnage (BRT) is the total capacity of all watertight enclosed spaces; thus, it indicates the total internal volume of the ship, which includes the following components:

The volume of the premises under the measurement deck (the volume of the hold under the deck);

The volume of the premises between the measurement and upper decks;

The volume of enclosed spaces located on the upper deck and above it (superstructure);

The amount of space between the hatch coamings.

The gross tonnage does not include the following enclosed spaces if they are intended and suitable exclusively for the named purposes and are used only for this:

Premises containing power and electric power plants, as well as air intake systems;

Rooms for auxiliary machinery that do not serve the main engines (for example, rooms for refrigeration plants, distribution substations, elevators, steering gears, pumps, processing machines on fishing vessels, chain boxes, etc.);

A vessel that has openings in the upper deck without strong watertight closures (measuring hatches and openings) is called a shelter boat or a hinged deck vessel; it has a lower register capacity due to such openings. Closed internal volumes in open spaces that have strong waterproof closures are included in the measurement. A condition for excluding open spaces from measurement is that they do not serve to accommodate or serve the crew and passengers. If the upper deck of double or multi-deck ships and the bulkheads of the superstructures are fitted with strong watertight closures, the interdeck space below the upper deck and the spaces of the superstructures are included in the gross tonnage. Such vessels are called full-range vessels and have a maximum allowable draft.

Net capacity (NRT) is the net volume to accommodate passengers and cargo, i.e. the sales volume. It is formed by subtracting the following components from the gross tonnage:

Premises for the crew and boatmasters;

Navigation rooms;

Premises for skipper's supplies;

Ballast water tanks;

Machine room (power plant premises).

Deductions from gross tonnage are made according to certain rules, in absolute terms or as a percentage. The deduction condition is that all these spaces are included in the gross tonnage first. In order to be able to verify whether the tonnage certificate is genuine and whether it belongs to this particular vessel, it indicates the dimensions of the identity (identification dimensions) of the vessel, which are easy to verify.

The cargo capacity of a ship is the volume of all holds in cubic meters, cubic feet, or 40 cubic feet "barrels". Speaking about the capacity of holds, the capacity is distinguished by piece (bales) and bulk (grain) cargo. This difference arises from the fact that in one hold, due to floors, frames, stiffeners, bulkheads, etc., bulk cargo can be placed more than piece cargo. The general cargo hold accounts for approximately 92% of the bulk cargo hold. The calculation of the vessel's capacity is carried out by the shipyard; the capacity is indicated on the tank diagram, and it has nothing to do with the official measurement of the vessel. Specific cargo capacity is the ratio of the holding capacity to the payload mass. Since the mass of the payload is determined by the mass of the required operating materials, the specific cargo capacity is subject to insignificant fluctuations. General cargo cargo ships have a specific tonnage of approximately 1.6 to 1.7 m3 / t (or 58 to 61 cubic feet).

Ship speed

Speed ​​is one of the most important operational characteristics of the vessel and one of the most important tactical and technical characteristics of the vessel, which determines the speed of its movement.

The speed of vessels is measured in knots (1 knot is equal to 1.852 km / h), the speed of inland navigation vessels (river, etc.) - in kilometers per hour.

There are the following types of vessel speed:

Ш The absolute speed of the ship is the speed measured by the distance traveled by the ship per unit of time relative to the ground (stationary object) along the line of the ship's path.

The safe speed of the ship is the speed at which appropriate and necessary action can be taken to avoid collision.

Ш Cruising (for warships, also the combat economic speed of a ship) is a speed that requires a minimum fuel consumption per mile traveled with a normal displacement and operation of naval and military equipment in a mode that ensures the full technical readiness of the main mechanisms for the development of full combat speed.

Ш The general speed of the ship is measured by the distance traveled by the ship per unit of time according to the general course.

Ш Permissible vessel speed - the established maximum speed, limited by the conditions of the combat mission being performed, the situation or the rules of navigation (when trawling, towing, in waves or shallow water, in accordance with the rules of the roadstead service or a mandatory regulation on the port)

Ш The highest speed of the vessel (or maximum) develops when the main power plant (main power plant) of the vessel is in forced mode, while ensuring the full combat readiness of the vessel. Prolonged forcing of the power plant can lead to its failure and loss of speed, as a result of which the vessel is resorted to reaching the highest speed in exceptional cases.

Ш The lowest speed of the vessel (or minimum) - the speed at which the vessel can still be kept on course (controlled with the help of the rudder).

W The relative speed of a vessel is measured by the distance traveled by the vessel per unit of time relative to the water.

Ш The full combat speed of the vessel (or full speed) is achieved when the power plant is operating in full power mode (without afterburner) with the simultaneous operation of all combat and technical means of the vessel, ensuring the full combat readiness of the vessel.

Ш Economic speed of the vessel (or technical and economic) - the speed achieved when the power plant is operating in the economic mode. At the same time, the task of the lowest fuel consumption per mile traveled is achieved while simultaneously ensuring the established combat readiness and domestic needs of the vessel.

Ш Squadron speed of a vessel (or assigned) is the speed of a connection or a group of vessels, set in each individual case based on the requirements of the task, the situation in the crossing area, navigational and hydrometeorological conditions.

Seaworthiness

ship speed cargo capacity unsinkability

Both civilian ships and warships must have seaworthiness.

The study of these qualities with the use of mathematical analysis is engaged in a special scientific discipline - the theory of the ship.

If a mathematical solution to the problem is impossible, then they resort to experience to find the necessary dependence and check the conclusions of the theory in practice. Only after a comprehensive study and verification by experience of all the seaworthiness of the vessel, they begin to create it.

Seaworthiness is studied in two sections: statics and dynamics of the vessel. Statics studies the laws of balance of a floating vessel and the related qualities: buoyancy, stability and unsinkability. Dynamics studies a vessel in motion and examines its qualities such as handling, pitching and propulsion.

Buoyancy

The buoyancy of a vessel is its ability to stay on the water at a certain draft, carrying the intended cargo in accordance with the purpose of the vessel.

Buoyancy

The ability of a vessel to stay on the water for a certain draft, while carrying a load, is characterized by a buoyancy margin, which is expressed as a percentage of the volume of watertight compartments above the waterline to the total watertight volume. Any violation of the impermeability leads to a decrease in the buoyancy reserve.

The equilibrium equation in this case has the form:

P = g (Vo? Vn) or: P = g V

where P is the weight of the vessel, g is the density of the water, V is the submerged volume, and is called the basic equation of buoyancy.

It follows from it:

Ш At a constant density g, a change in the load P is accompanied by a proportional change in the immersed volume V until a new equilibrium position is reached. That is, with an increase in the load, the vessel "sits" in the water deeper, with a decrease, it floats higher;

Ш With a constant load P, the change in density r is accompanied by an inversely proportional change in the immersed volume V. Thus, a ship sits deeper in fresh water than in salt water;

Ш A change in the volume V, other things being equal, is accompanied by a change in the draft. For example, when ballasting with seawater or emergency flooding of compartments, it can be considered that the ship did not accept the cargo, but reduced the submerged volume, and the draft increased - the ship sits deeper. When water is pumped out, the opposite happens.

The physical meaning of the buoyancy margin is the volume of water that a vessel can take (say, when the compartments are flooded) while still afloat. A 50% buoyancy reserve means that the waterproof volume above the waterline is equal to the volume below it. For ships, reserves of 50-60% and more are characteristic. It is believed that the more stock you managed to get during the construction, the better.

Neutral buoyancy

When the volume of taken water is exactly equal to the buoyancy margin, it is considered that the buoyancy is lost - the margin is 0%. Indeed, at this moment the ship is sinking along the main deck and is in an unstable state, when any external influence can cause it to go under the water. As a rule, there is no shortage of influences. In theory, this case is called neutral buoyancy.

Negative buoyancy

When receiving a volume of water greater than the buoyancy reserve (or any weight larger in weight), it is said that the vessel receives negative buoyancy. In this case, it is unable to swim, but can only sink.

Therefore, a mandatory buoyancy margin is established for the vessel, which it must have in an intact condition for safe navigation. It corresponds to full displacement and is marked with a waterline and / or load line.

The straight-sidedness hypothesis

To determine the effect of variable weights on buoyancy, an assumption is used under which it is considered that the reception of small (less than 10% of displacement) weights does not change the area of ​​the operating waterline. That is, the change in draft is considered as if the body is a straight prism. Then the displacement directly depends on the draft.

Based on this, the factor of the change in precipitation is determined, usually in t / cm:

where S is the area of ​​the effective waterline, q is the amount of change in the load in tons, required to change the draft by 1 cm. In the reverse calculation, it allows you to determine whether the buoyancy margin has gone beyond the permissible limits.

Stability

Stability is the ability of the vessel to resist the forces that caused its inclination, and after the cessation of the action of these forces, return to its original position.

The inclination of the vessel is possible for various reasons: from the action of the oncoming waves, due to asymmetric flooding of the compartments during a breach, from the movement of goods, wind pressure, due to the reception or consumption of goods, etc.

Stability types:

Ш Distinguish between initial stability, i.e. stability at low heel angles, at which the edge of the upper deck begins to enter the water (but not more than 15 ° for high-sided surface vessels), and stability at high inclinations.

Ш Depending on the plane of inclination, a distinction is made between lateral stability during roll and longitudinal stability during differential. Due to the elongation of the shape of the ship's hull, its longitudinal stability is significantly higher than the transverse one, therefore, for the safety of navigation, it is most important to ensure proper lateral stability.

Ш Depending on the nature of the acting forces, static and dynamic stability are distinguished.

Static stability - considered under the action of static forces, that is, the applied force does not change in magnitude.

Dynamic stability - considered under the action of changing (that is, dynamic) forces, such as wind, sea waves, cargo movement, etc.

Initial stability

If the vessel under the influence of the external heeling moment MKR (for example, wind pressure) gets a roll at an angle and (the angle between the initial WL0 and the current WL1 water lines), then, due to the change in the shape of the underwater part of the vessel, the center of the value C will move to point C1 (Fig. 2 ). The support force y V will be applied at point C1 and directed perpendicular to the current waterline WL1. Point M is located at the intersection of the diametrical plane with the line of action of the supporting forces and is called the transverse metacentre. The force of the ship's weight P remains at the center of gravity G. Together with the force yV, it forms a pair of forces that prevents the inclination of the ship by the heeling moment of the MKR. The moment of this pair of forces is called the restoring moment MV. Its value depends on the leverage l = GK between the forces of weight and support of a tilted vessel:

MB = Pl = Ph sin and,

where h is the elevation of point M above the CG of the vessel G, called the transverse metacentric height of the vessel.

Fig. 2. The action of the forces during the list of the ship

It can be seen from the formula that the value of the restoring moment is the greater, the greater h. Consequently, metacentric height can serve as a measure of stability for a given vessel.

The value of h of a given vessel at a certain draft depends on the position of the center of gravity of the vessel. If the cargo is positioned so that the center of gravity of the vessel takes a higher position, then the metacentric height will decrease, and with it the shoulder of static stability and the restoring moment, i.e., the stability of the vessel will decrease. With a decrease in the position of the center of gravity, the metacentric height will increase, and the stability of the vessel will increase.

The metacentric height can be determined from the expression h = r + zc - zg, where zc is the elevation of the CV over the OB; r is the transverse metacentric radius, i.e., the elevation of the metacentre above the CV; zg - elevation of the ship's CG above the main one.

In a constructed ship, the initial metacentric height is determined empirically - by heeling, i.e., the transverse inclination of the ship by moving a load of a certain weight, called roll-ballast.

High roll stability

Fig. 3. Static stability diagram.

As the ship's heel increases, the restoring moment first increases, then decreases, becomes equal to zero, and then not only does not prevent inclination, but, on the contrary, contributes to it (Fig. 3)

Since the displacement for a given load state is constant, the restoring moment changes only due to a change in the lateral stability arm lst. According to the calculations of lateral stability at large angles of roll, a static stability diagram is built, which is a graph expressing the dependence of lst on the roll angle. The static stability diagram is built for the most typical and dangerous cases of ship loading.

Using the diagram, you can determine the roll angle from the known heeling moment, or, conversely, find the heeling moment from the known roll angle. The initial metacentric height can be determined from the static stability diagram. For this, a radian equal to 57.3 ° is laid from the origin of coordinates, and the perpendicular is restored to the intersection with the tangent to the curve of the stability arms at the origin. The segment between the horizontal axis and the point of intersection in the scale of the diagram and will be equal to the initial metacentric height.

Influence of liquid cargo on stability. If the tank is not filled to the top, that is, it has a free surface of the liquid, then when tilted, the liquid will overflow towards the bank and the center of gravity of the vessel will shift in the same direction. This will lead to a decrease in the stability shoulder, and, consequently, to a decrease in the restoring moment. Moreover, the wider the tank, in which there is a free surface of the liquid, the more significant the decrease in lateral stability will be. To reduce the effect of the free surface, it is advisable to reduce the width of the tanks and strive to ensure that during operation there is a minimum number of tanks with a free surface of the liquid.

Influence of bulk cargo on stability. When transporting bulk cargo (grain), a slightly different picture is observed. At the beginning of the inclination, the weight does not move. Only when the roll angle exceeds the angle of repose does the load begin to spill over. In this case, the poured cargo will not return to its previous position, but, remaining at the side, will create a residual heel, which, with repeated heeling moments (for example, squalls), can lead to a loss of stability and overturning of the vessel.

To prevent grain spilling in the holds, suspended longitudinal semi-bulkheads are installed - shifting boards, or bags with grain are placed over the grain poured in the hold - bagging the cargo.

Effect of a suspended load on stability. If the cargo is in the hold, then when it is lifted, for example, by a crane, there is, as it were, an instantaneous transfer of the cargo to the suspension point. As a result, the ship's CG will shift vertically upward, which will lead to a decrease in the restoring moment arm when the ship receives a roll, i.e., to a decrease in stability. In this case, the decrease in stability will be the greater, the greater the mass of the load and the height of its suspension.

Walking speed

The ability of a vessel to move in the environment at a given speed at a certain power of the main engines and the corresponding propulsion unit is called propulsion.

The ship moves on the border of two environments - water and air. Since the density of water is about 800 times the density of air, the resistance of water is much greater than the air resistance. The water resistance force consists of frictional resistance, shape resistance, wave resistance, and protruding resistance.

Due to the viscosity of water between the hull of the ship and the layers of water closest to the hull, friction forces arise, overcoming which part of the power of the main engine is spent. The resultant of these forces is called the frictional resistance RT. The frictional resistance also depends on the speed, on the wetted surface of the ship's hull and on the degree of roughness. The value of roughness is influenced by the quality of painting, as well as the fouling of the underwater part of the hull by marine organisms. To prevent frictional resistance from increasing for this reason, the vessel is subjected to periodic docking and cleaning of the underwater part. The frictional resistance is determined by calculation.

When a viscous fluid flows around the ship's hull, the hydrodynamic pressures are redistributed along its length. The resultant of these pressures, directed against the movement of the vessel, is called the form resistance RФ. Resistance to shape depends on the speed of the vessel and on its shape. In a bluff shape, vortices are formed in the stern of the vessel, which leads to a decrease in pressure in the area and an increase in the resistance to the shape of the vessel. The impedance RВ arises due to the formation of waves in the zones of high and low pressure during the movement of the vessel. Wave formation also consumes part of the energy of the main engine. The impedance depends on the speed of the vessel, the shape of its hull, as well as the depth and width of the fairway. The resistance of the protruding parts RVCh depends on the frictional resistance and on the shape of the protruding parts (rudders, bilge keels, propeller shaft brackets, etc.). Form resistance and wave resistance combine to form a residual resistance that can only be calculated approximately. To accurately determine the value of the residual resistance, ship models are tested in the experimental basin.

Controllability

Controllability refers to the ability of the vessel to be agile and steady on its course. Agility is the ability of a vessel to obey the rudder, and heading stability is the ability to maintain a given direction of movement. Due to the influence of various disturbing factors (waves, wind) on the movement of the vessel, constant steering intervention is required to ensure stability on the course. Thus, the qualities characterizing the ship's handling are contradictory. So, the more nimble the vessel, that is, the faster it changes the direction of its movement when turning the rudder, the less stable it is on the course.

When designing a ship, the optimal value of one quality or another is chosen depending on the purpose of the ship. The main quality of passenger and cargo ships making long-distance voyages is stability on the course, and of tugboats - agility.

The ability of a ship to spontaneously deviate from its course under the influence of external forces is called yaw.

Rice. 4 Diagram of the forces acting on the ship when shifting the rudder blade.

To ensure the required controllability, one or more rudders are installed in the stern of the vessel (Fig. 4). If the rudder is shifted to an angle b on a vessel moving at a speed of v, then the pressure of the incoming water flow will begin to act on one side of the rudder - the resultant of the hydrodynamic forces P, applied at the center of pressure and directed perpendicular to the rudder surface. Let us apply in the center of gravity of the vessel the mutually balanced forces P1 and P2, equal and parallel to P. The forces P and P2 form a pair of forces, the moment of which MWP turns the ship to the right, MWP = Pl, where the shoulder of the pair is l = GA cosb + a.

The force P1 is decomposed into the components Q = P1 cosb = P cosb and R = P1 sinb = Psinb. Force Q causes drift, i.e. movement of the ship perpendicular to the direction of movement, while force R reduces its speed.

Fig. 5. Elements of the vessel's circulation: DЦ - circulation diameter; DТ - tactical circulation diameter; в - drift angle.

Thus, immediately after shifting the rudder to the side of the ship's CG, it will begin to describe in the horizontal plane a curve that gradually turns into a circle called circulation (Fig. 5). The diameter of the circle DЦ, which will begin to describe the center of gravity of the vessel after the beginning of the established circulation, is called the diameter of the circulation. The distance between the DP before the beginning of the circulation and after the turn of the vessel by 180 ° is the tactical diameter of the circulation DT. The measure of a ship's turnability is the ratio of the circulation diameter to the length of the ship. The angle between the DP of the vessel and the tangent to the trajectory of the vessel during the circulation, drawn through the center of gravity of the vessel, is called the drift angle.

When moving in circulation, the vessel heels on the side opposite to the rudder shift, under the action of the centrifugal force of inertia applied at the center of gravity of the vessel, and hydrodynamic forces applied to the underwater part of the vessel and the rudder. To ensure good controllability at low speeds (in a confined water area, when mooring), when a conventional rudder is ineffective, active controls are used.

Swing refers to the vibrational motion that the vessel makes about its equilibrium position.

Oscillations are called free (in calm water) if they are made by the vessel after the cessation of the action of the forces that caused these oscillations (gust of wind, jerk of the towing rope). Due to the presence of resistance forces (air resistance, water friction), free oscillations gradually damp and stop. Oscillations are called forced if they occur under the action of periodic disturbing forces (incident waves).

The pitching is characterized by the following parameters (Fig. 6):

W amplitude and - the greatest deviation from the equilibrium position;

W swing - the sum of two consecutive amplitudes;

Ш period T - the time of two full swings;

Sh acceleration.

Fig. 6. Pitching parameters: U1 and U2 amplitudes; u1 + u2 span.

Swaying complicates the operation of machines, mechanisms and devices due to the effect of the arising forces of inertia, creates additional loads on the strong connections of the ship's hull, and has a harmful physical effect on people.

Distinguish between side, pitching and heaving. When rolling, vibrations are performed around the longitudinal axis passing through the center of gravity of the vessel, with pitching - around the transverse one. Roll at a short period and large amplitudes becomes gusty, which is dangerous for mechanisms and is difficult for people to tolerate.

The period of free vibrations of a vessel in calm water can be determined by the formula T = c (B / vh), where B is the width of the vessel, m; h - transverse metacentric height, m; с - coefficient equal to 0.78 - 0.81 for cargo ships.

It can be seen from the formula that with an increase in the metacentric height, the rolling period decreases. When designing a ship, they strive to achieve sufficient stability with moderate smoothness of pitching. When sailing on rough seas, the boatmaster must know the period of natural oscillations of the vessel and the period of the wave (the time between the running onto the vessel of two adjacent ridges). If the period of natural oscillations of the vessel is equal to or close to the period of the wave, then a resonance phenomenon occurs, which can lead to overturning of the vessel.

When pitching, it is possible either to flood the deck, or when the bow or stern is exposed, they hit the water (slamming). In addition, the acceleration that occurs during pitching is much greater than during rolling. This circumstance must be taken into account when choosing mechanisms to be installed in the bow or in the stern.

Roll is caused by the change in the support forces as the wave travels under the boat. The period of heave is equal to the period of the wave.

To prevent undesirable consequences from the action of pitching, shipbuilders use means that contribute, if not to a complete cessation of pitching, then at least to moderate its swing. This problem is especially acute for passenger ships.

To moderate pitching and flooding the deck with water, a number of modern ships make a significant rise of the deck in the bow and stern (sheerness), increase the camber of the bow frames, design ships with a tank and poop. At the same time, water deflectors are installed in the nose on the tank.

To moderate the roll, passive uncontrolled or active controlled roll dampers are used.

Fig. 7. Scheme of action of the zygomatic (lateral) keels.

The passive dampers include the zygomatic keels, which are steel plates installed over 30-50% of the ship's length in the cheekbone region along the water stream (Fig. 7). They are simple in design, reduce the pitching amplitude by 15 - 20%, but provide significant additional water resistance to the movement of the vessel, reducing the speed by 2-3%.

Passive tanks are tanks installed on the sides of the vessel and interconnected at the bottom by overflow pipes, at the top - by an air channel with an isolation valve that regulates the transfer of water from board to board. It is possible to adjust the cross-section of the air channel in such a way that the liquid, when rolling, will overflow from side to side with a delay and thereby create a heeling moment that counteracts the inclination. These tanks are effective in pumping modes with a long period. In all other cases, they do not moderate, but even increase its amplitude.

In active tanks (Fig. 8), water is pumped by special pumps.

Fig. 8. Active sedative tanks.

At present, active side rudders are most often used on passenger and research vessels (Fig. 9), which are conventional rudders installed in the widest part of the vessel slightly above the cheekbone in an almost horizontal plane. With the help of electro-hydraulic machines, controlled by signals from sensors that react to the direction and speed of the inclination of the vessel, it is possible to change their angle of attack. So, when the vessel is tilted to the starboard side, the angle of attack is set on the rudders so that the lifting forces that arise in this case create moments opposite to the inclination. The efficiency of the rudders on the move is quite high. In the absence of rolling, the rudders are removed into special niches in the body so as not to create additional resistance. The disadvantages of rudders include their low efficiency at low strokes (below 10 - 15 knots) and the complexity of the automatic control system.

Fig. 9. Active lateral rudders: a - general view; b - action scheme; c - the forces acting on the side rudder.

There are no dampers for pitching control.

Unsinkability

Unsinkability is the ability of a vessel to stay afloat, maintaining sufficient stability and some buoyancy, when one or more compartments are flooded.

The mass of water poured into the hull changes the landing, stability and other seaworthiness of the vessel. The unsinkability of a vessel is ensured by its buoyancy: the larger the buoyancy, the more seawater it can take while staying afloat.

When installing longitudinal watertight bulkheads on a ship, it is necessary to carefully analyze their effect on unsinkability. On the one hand, the presence of these bulkheads can cause an unacceptable heel after flooding the compartment, on the other hand, the absence of bulkheads will adversely affect stability due to the large area of ​​the free water surface. Thus, the division of the vessel into compartments should be such that in case of a side breach, the vessel's buoyancy is exhausted before its stability: the vessel should sink without capsizing.

To straighten the vessel, which has received a heel and a trim as a result of a hole, forced counterflooding of preselected compartments is carried out with the same magnitude, but with inverse moments. This operation is carried out using the unsinkability tables - a document with the help of which it is possible to determine the landing and stability of the vessel after damage with a minimum amount of time, select the compartments to be flooded, and also evaluate the results of straightening before its implementation in practice.

The unsinkability of sea vessels is regulated by the Register Rules developed on the basis of the International Convention for the Safety of Life at Sea 1974 (SOLAS-74). In accordance with these rules, a ship is considered unsinkable if, after the flooding of any one compartment or several adjacent ones, the number of which is determined depending on the type and size of the ship, as well as the number of people on board (usually one, and for large ships - two compartments ), the vessel dives no deeper than the diving limit. In this case, the initial metacentric height of the damaged vessel should be at least 5 cm, and the maximum shoulder of the static stability diagram should be at least 10 cm, with a minimum length of the positive section of the diagram of 20 °.

Sources of

1.http: //www.trans-service.org/ - 15/12/2015

2.http: //www.midships.ru/ - 15/12/2015

3.ru.wikipedia.org - 12/15/2015

4.http: //flot.com - 15/12/2015

5. Sizov, V. G. Theory of the ship: a textbook for universities. Odessa, Phoenix, 2003 .-- 12/15/2015

6.http: //www.seaships.ru - 15/12/2015

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