Coefficient of the general completeness of the ship's hull. Analysis of consumer properties and indicators of the range of electric drills. Main dimensions of transport vessels

The main, or main, geometrical dimensions of the vessel are length L, width B, depth H, freeboard F, draft T and overall height of the vessel with superstructures h, (Figure 5). The ratio of these dimensions characterizes the shape of the vessel and its main qualities.


Figure 5 - Theoretical and overall dimensions of the vessel

There are the following main dimensions:

a) theoretical (calculated), measured according to the theoretical drawing without taking into account the thickness of the outer shell of the hull;

b) practical (constructive), measured taking into account the thickness of the skin;

c) overall (largest), measured between the extreme non-removable protruding parts of the vessel.

The length of the vessel L is measured in DP between the perpendiculars along the GVL, and in the presence of a cruising stern, between the forward and stern perpendiculars, drawn along the axis of rotation of the rudder. Distinguish the greatest length of the vessel L max as the greatest distance in the center plane. Breadth B is measured at the cargo waterline at its widest point. Overall width B max is measured in the midship plane between fixed parts (including fenders).

The ship's draft, T, is measured amidships as the distance from the base plane to the cargo waterline. If the vessel is trimmed, then the draft T cf is measured as the half-sum of the draft in the bow T H and in the stern T K

The draft in the bow T N and in the stern T k, in turn, is measured from both sides of the vessel and calculated by the dependencies

Maximum draft T max. there is an overall dimension along the perpendicular from the GVL to the protruding outer edges of the bottom skin or protruding parts of the rudder, propeller or their enclosures.

Depth H is the vertical distance from the base plane to the topside line, measured in the midship plane. Freeboard F is the distance from the GVL to the topside line in the midship plane. The height of the vessel h is the overall dimension from the GVL to the highest point of the vessel. You need to know this size when passing ships under bridges. To characterize the shape of the ship and some of its qualities, the relationship of the above dimensions of the ship to each other is of great importance.

The L / B ratio affects the speed of the boat. The larger it is, the sharper the vessel, the less resistance to movement. Most often, this ratio is within 48.

The L / H ratio affects the strength of the vessel. The larger it is, the more weight additional materials are needed to ensure the desired strength of the vessel. For tugboats this ratio is within 812, for cargo ships it reaches 50.

The B / L ratio affects the stability of the vessel. With its increase, the initial stability increases.

The B / T ratio affects stability, propulsion and course stability. The more W / T, the more stable the ship; for tugboats B / T = 2 4, for cargo ships up to 12.

The L / T ratio affects the turnability of the boat; the smaller it is, the more maneuverable the vessel is (excluding water jet vessels, where the turnability is ensured by the release of water through special side nozzles).

The H / T ratio affects the stability, strength and tonnage of a vessel. For motorboats, it ranges from 1.2 to 3.6; for cargo ships - from 1.05 to 1.6.

For a better understanding of the ship's forms, dimensionless completeness coefficients are also used, obtained from comparing the areas and volumes characteristic of the ship with the correct simplest geometric areas and volumes. Completeness coefficients are used at the initial design stage, as well as when solving many practical issues for quick and approximate identification of some of the main elements of the vessel. To obtain these coefficients, it is customary to designate the GVL area through S (it characterizes the completeness of the ship's contours in the plan - in horizontal section); midship area through and (it characterizes the completeness of the ship's contours in cross section); the area of ​​diameter through A (it characterizes the completeness of the ship's contours in the longitudinal section); the volume of the underwater part of the vessel through V, which is the volumetric displacement, which characterizes the total completeness of the vessel's contours.

The ratios of the named areas and volumes to the areas and volumes of geometrically correct figures with the same overall dimensions are called the completeness coefficients of the underwater part of the vessel.

The coefficient of completeness of GVL b is the ratio of the area of ​​the cargo waterline S to the area of ​​a rectangle with sides L and B, i.e.

navigational vessel buoyancy cargo capacity

Its values ​​for river cargo ships range from 0.84 to 0.9.

The coefficient of completeness midship is the ratio of the area of ​​the midship frame to the area of ​​a rectangle with sides B and T, i.e.

Its value for river cargo ships is 0.96? 0.99.

The coefficient of completeness of the diameter r is the ratio of the area of ​​the diameter A to the area of ​​a rectangle with sides L and T, i.e.

This coefficient is rarely found in calculation practice.

The coefficient of the completeness of the volumetric displacement d is the ratio of the volume of the vessel V to the volume of the parallelepiped with sides L, B and T, i.e.

Its values ​​fluctuate within 0.85? 0.90.

The coefficient of the longitudinal completeness of the displacement q is the ratio of the volumetric displacement of the vessel V to the volume of the prism with the base equal to the area of ​​the midsection and and the height L, i.e.

Coefficient vertical completeness displacement h is the ratio of the volumetric displacement V to the volume of the prism with a base equal to the area of ​​the cargo waterline S and height T, i.e.

The coefficient of lateral displacement w is the ratio of the volumetric displacement of the vessel V to the volume of the prism with the base equal to the area of ​​diameter A and height B, i.e.

This coefficient is almost never found in calculation practice.

Thus, the completeness coefficients b, c, d and e are basic, and c, h and w are derivatives.


affects the running speed, stability, unsinkability, carrying capacity, cargo capacity, but selected from the condition of reducing the resistance to the movement of the vessel (from hydromechanical considerations).

R / D


Figure 8 - Curve of the dependence of the resistance to the movement of the vessel on the coefficient overall completeness d

At δ cr

The speed increases sharply ® the power of the main engine increases, the mass of fuel

R ® N ® main engine power, fuel weight

But the mass of the hull is reduced, the technology is simplified, the holds are more convenient (box form)

Therefore, they try to take δ close to δ cr.

The magnitude of the drop in the speed of the vessel on waves depends on the completeness of the vessel and the size. The larger the vessel, the less its fullness affects the magnitude of this speed drop. Therefore, for large vessels, higher values ​​of δ can be assumed.

δ = a - b * Fr

where a and b are numerical coefficients depending on the type of vessel.

Table 10 Calculation formulas for determining δ

Type of vessel Fr Calculation formulas Notes (edit)
General purpose dry cargo vessels 0,19-0,25 δ = 1.07 - 1.68 Fr
0,25-0,29 δ = 1.21 - 2.30 Fr
Tankers, bulk carriers - 0.03-0.05 more than dry cargo ships Large dimensions, moderate speeds, a large proportion of ballast crossings - the average value of δ for a round trip is less than with the design displacement in full load. In addition, δ allows ¯ main dimensions (T in full load), which is desirable for large ships
Passenger ships, ferries 0,25-0,33 δ = 0.77 - 0.78 Fr It is desirable to increase the main dimensions (primarily L and B) for the placement of premises (cabins, public premises, etc.) ®¯ δ
0,30-0,40 δ = 0.40 Fr
0,40-0,60 δ = 0.50

Coefficient of completeness of the midship frame already committed if selected δ and j... However, when choosing it, the following circumstances must be borne in mind.

On relatively slow and medium speed vessels(Fr<0,30)b take as much as possible to sharpen the tip of full vessels (reduce drag). Upper limit ( b = 1) limited by the possibility of constructing a theoretical drawing without noticeable kinks in the waterline at the boundaries of the cylindrical insert.

For determining b the following expressions can be used:

At δ <0,650 b =0,813 + 0,267 δ ;

At 0.615< δ <0,800 b =0,928 + 0,080 δ ;

At δ > 0,800 b =0,992.

For less complete, relatively fast ships, for which there is no reason for a special sharpening of the extremities, the following values ​​are recommended b :

Table 11 Values b for relatively fast ships (Fr > 0,30)

Fr 0,34 0,38 0,41 0,46 0,50
b 0,925 0,875 0,825 0,800 0,790
a

Coefficient of completeness of the area of ​​the constructive waterline(LWL) affects mainly the stability, unsinkability and cargo capacity of ships. At the same time, it is geometrically related to the shape of the frames, taper angles and coefficients δ and j... Therefore, initially it is taken depending on these coefficients, then refining it when developing a theoretical drawing.

For vessels with U-shaped and V-shaped frames, the following ratios can be used:

a = δ + 0.10 and a = δ = 0.12, respectively.

The main dimensions of the vessel are: length (L), width (B), depth (H or D), draft (T or d)

Length of the vessel (L). Distinguish length:

According to the constructive overhead line / Lkvl / - the distance (in the KVL plane) between the points of its intersection with the stem and sternpost;

Between perpendiculars (Lpp) - distance in KVL area between bow and stern perpendiculars; the nasal perpendicular passes through the extreme forward point of the LWL, the stern one - through the axis of the rudder stock;

The greatest / Lnb / - the distance between the extreme points of the bow and stern extremities;

Overall / Lgb / - maximum length plus protruding parts.

The width of the vessel B. There are different widths:

According to KVL / VKVL / - the distance in the KVL area in the widest part of the hull between the points of its intersection with the inner surface of the hull skin;

In the midship / Vmd / - the same as Vkvl, but in the plane of the midship frame;

The greatest / Vnb / - the distance in the widest part of the body between its extreme points, excluding protruding parts

Overall / Vgb / - Vnb including protruding parts.

Draft of the vessel / d, T / - distance in the plane amidships-frame between the main square. (OP) and KVL at the calculated overhead line.

Landing of the vessel - average draft, trim (difference between draft and stern), roll (bank angle). Control over the landing of the vessel during operation is carried out according to the marks of the recess, which are inscribed in Arabic numerals on both sides on the stem, in the midship area, sternpost at a distance of 10 cm from each other (in decimeters).

Depth / D, H / - vertical distance in the midship plane at the side from the inner edge of the vertical keel to the upper edge of the upper deck beam.

Freeboard F = D - d or H - T

Main dimension ratios(L / B, B / T, H / T, L / H, B / H are the primary characteristics of the shape of the ship's hull, and they also affect the seaworthiness of the ship.
COMPLETENESS FACTORS of the underwater part of the ship's hull also serve as a characteristic of the shape of the hull and, in addition, for approximate calculations of the main dimensions of the ship.

S / LB - coefficient of completeness of the waterline area

= / ВТ - coefficient of completeness of the midship frame

V / LBT - coefficient of overall completeness

V / L - coefficient of longitudinal fullness

V / ST - coefficient of vertical completeness

The table of ratios of the main dimensions and completeness coefficients is given in Ф on page 62, table 6

When designing the shape of the ship, a number of experimental values ​​are taken into account - shipbuilding characteristics, which determine not only the various qualities of the ship, but also its efficiency. The shape characteristics describe the shape of the ship and thus its appearance through the relationship between the main dimensions of length, width, depth and draft, as well as through the relationship between the waterline area, frame area and displacement with the main dimensions. The shape characteristics are usually related to the design settlement. In particular, they affect the behavior of a ship at sea, and when choosing relative values, they take into account, first of all, the requirements for this type of ship.

Length to width ratio L / B affects mainly the speed qualities of the vessel, its maneuverability and stability. Large values L / B(long narrow vessels) have a beneficial effect on the speed of the vessel and its stability on the course. Therefore, passenger and fast cargo ships are of great importance. L / B... At a given speed and displacement under these conditions, the required engine power is reduced, and heading stability is improved due to the larger lateral surface of the underwater part of the vessel (projection area). The upper limit of the relationship L / B is determined by the required lateral stability of ships. In addition to these advantages, the large ratio of IW allows to increase the volume of the hull of passenger and large cargo ships and rationally distribute the premises on them. On the efficiency of these vessels, fluctuations in values L / B almost does not affect. Small values L / B(short wide vessels) provide good maneuverability and stability. For this reason, tugs, which must have good agility and often experience jerks affecting lateral stability when the cable is pulled laterally, have a particularly low L / B.
Length to depth ratio L / H for a free beam (ship) is the ratio of the beam length to its height. This ratio is critical to the longitudinal strength and bending of the ship's hull. Small L / H, i.e. a large depth at a given length, requires smaller dimensions for the upper and lower belts of the ship's hull and gives a lower deflection under a longitudinal load than a large one L / H... Smaller flange dimensions are possible as a result of the fact that the moment of resistance required to ensure longitudinal strength is favorably affected by an increase in the height of the beam. For this reason, long midship superstructures are included in the upper chord (high depth H) of the vessel. For reasons of strength, as well as depending on the navigation area, the following ratios are taken for the maximum permissible: with unlimited navigation L / H= 14; with a large coastal voyage - L / H= 15; for the North Sea - L / H= 16; for the Baltic Sea - L / H= 17; with small coastal voyages - L / H= 18. For inland navigation vessels that are not subject to significant loads from waves, take significantly larger values L / H(up to 30).

Width to draft ratio B / T predominantly determines the lateral stability and resistance to the movement of the vessel. Since the stability increases in proportion to the third degree of the width, vessels with a small B / T(narrow vessels with a large draft) have a lower initial stability than vessels with a large B / T(wide vessels with shallow draft); however, the latter are prone to a sharp roll in waves. Since, for example, tugs, due to their low freeboard, are not very stable at significant inclinations, they, like all other small vessels, usually have a large B / T, while large, high-sided vessels have lower values B / T... Movement resistance in vessels with high B / T more than ships with small B / T.

Board height to draft ratio H / T characterizes the displacement margin, that is, the displacement of the non-submerged watertight part of the ship's hull, and significantly affects the sunset angle of the static stability diagram. The more H / T, the greater the freeboard and, consequently, the buoyancy of the vessel. In addition, the sunset angle of the static stability diagram is significantly increased due to the large freeboard. Thus, ships with a large H / T, for example, passenger ships, are more stable than ships with small H / T, since the former at high inclinations of the vessel (60 ° and more) still have a restoring moment, which significantly reduces the danger of overturning.

Completeness factors

Coefficient of completeness of the structural waterline α - the ratio of the KVL area to the area of ​​a rectangle, the sides of which are equal L and V... The lower this coefficient, the sharper the waterline. Usually ships with large L / B(long narrow vessels) have higher airflow factor than short wide vessels.
Coefficient of completeness of midship-frame β is the ratio of the submerged area of ​​the mid-frame to the area of ​​a rectangle with sides V and T... It is significantly influenced by the shape of the frames, as well as the rise and radius of the cheekbone. The greater the lift and radius of the chine (for example, in small fishing vessels, tugs and icebreakers), the lower the coefficient of fullness of the midship frame.
Overall completeness ratio δ - the ratio of the volume of the underwater part of the vessel to the volume of the body with sides L X V X T... This coefficient characterizes to some extent the shape of the vessel in terms of sharpness and has a significant effect on the displacement (carrying capacity); on the other hand, with growth δ the resistance of the vessel increases. On the contrary, at a given displacement, with a decrease in the completeness ratio, the vessel becomes longer without becoming heavier, since the required engine power at a given speed decreases, as a result of which the need for fuel becomes less. Such a vessel will also be more cost effective because it is longer and therefore can have more holds.

Longitudinal completeness coefficient φ - the ratio of the displacement to the volume of the body, the base of which is the area of ​​the midship-frame, and the height is the length of the vessel. This factor is always slightly higher than the overall completeness factor, and better characterizes the sharpness of the ends of the vessel. A large coefficient of completeness of the midship frame means full ends of the vessel, a small one - on the contrary, narrow. However, when comparing two ships, one must always take into account the ratio L / B... For large L / B(long narrow vessels) the coefficients of fullness of the midship-frame or overall fullness may be greater than with a small L / B(short wide vessels); the contours do not become fuller.

The above completeness factors are interrelated, so they cannot be chosen arbitrarily. The listed shape characteristics (relative values ​​and completeness coefficients) largely determine the behavior of the vessel at sea, the resistance to movement and the profitability of the vessels and, moreover, mutually influence each other.

4.4.3 Resistance to movement - Froude number

When moving at the bow and stern of the vessel, waves are created, which become larger with increasing speed. This is due to the fact that with an increase in the speed of movement, a significant vacuum arises in the aft part of the vessel, and a zone of increased pressure in the bow. The energy spent on the formation of waves is the characteristic impedance, the magnitude of which is determined by the speed and length of the vessel. The characteristic of the wave resistance of a vessel is the ratio of speed to length, called the Froude number:

Fr = v / √gL

This characteristic makes it possible to compare vessels of different sizes, which makes it possible to determine the drag and thus the engine power for a vessel under construction using model towing tests. The speeds of the vessel and the model are related as square roots of their linear dimensions:

This means, for example, that a ship under construction with a length of 130 m, a width of 14 m, a draft of 6.6 m, a displacement of 5900 t and a speed of 25 knots (12.86 m / s) corresponds to a model speed of 2.572 m / s with a length of 5, 2 m. At this speed, the model has a wave formation, which is geometrically similar to the wave formation of a full-scale vessel. The resistance measured in this case contains, however, not only wave resistance, but also one more component - frictional resistance, which arises due to the braking effect of water flowing past the housing. The frictional resistance depends on the area of ​​the wetted surface of the body, on its quality (degree of roughness) and on the speed. It can be calculated with sufficient accuracy from experimental data for both the model and the vessel. If the impedance of the model is reduced by the calculated coefficient of friction, the resulting impedance of the model is obtained. When recalculating, the provision is in effect that the wave impedances of two geometric similar bodies - the ship and the model - are related as their displacement. But this simple relationship is true only when the ship and model are moving at comparable speeds, so that geometrically similar waveforms occur. If the calculated frictional resistance is added to the wave resistance (determined by experiments on the model), the total resistance of the vessel is obtained. In our example, during model tests, a wave resistance of 0.31 MN was determined and, by calculation, a frictional resistance of 0.35 MN. The total resistance of the vessel is thus 0.66 MN. Of course, in the final determination of the required power of the motors, air and vortex resistances must also be taken into account.

The share of wave drag and frictional drag in total drag depends on the shape of the ship and its speed. For large, slow-moving vessels, the wave drag is about 20%, and for very high-speed vessels it is up to 70% of the total drag. Ship load components

The displacement of a vessel is the mass of the volume of water in tons displaced by the hull to the permissible cargo waterline, which, according to Archimedes' law, is equal to the mass of the vessel. The mass of the ship is the sum of the own mass of the ship and its carrying capacity (payload mass).

The empty weight of the ship includes:

The hull of the vessel, equipped with inventory and spare parts; a ready-to-use power plant with inventory and spare parts; water in boilers, pipelines, pumps, condensers, coolers;

Fuel in all production pipelines;

Carbon dioxide and brine or other operating materials in refrigeration and fire-fighting systems;

Residual water in bilges and cisterns that cannot be removed by pumps, as well as waste water and moisture.

Carrying capacity in tons with volume of holds and operating speed is the most important economic characteristic of a vessel; it must be guaranteed by the shipyard, since understating it is punishable by contractual fines. Gross tonnage - vessel deadweight - includes all masses that do not relate to the lightweight of the vessel, such as:

Payload (including mail);

Crew and passengers with luggage;

All operating materials (fuel supplies, lubricants, oils, boiler feed water) in storage tanks;

Ship supplies such as paints, kerosene, wood, resin, ropes;

Crew and passenger supplies (drinking water, washing water and provisions);

Load securing equipment such as wooden supports, tarpaulins and masts, longitudinal bulkheads for bulk cargo;

Special equipment for special types of vessels, for example fishing equipment (nets, ropes, trawls).

There are certain ratios between the most important components of the load, which also affect the efficiency of ships.
The ratio of the empty displacement of a ship to its full load depends mainly on the type of ship, the area of ​​navigation, the speed of the ship and on the structure of the hull. For example, the empty displacement of a cargo ship at normal operating speed (14-16 knots) without ice reinforcements is approximately 25% of the displacement in full load. The icebreaker, which is supposed to have powerful engines and a particularly reinforced hull, has an empty displacement of about 75% of its total displacement. If a cargo ship has a total displacement of 10 thousand tons, then the empty displacement is about 2.5 thousand tons, and its deadweight is about 7.5 thousand tons, while a large icebreaker of the same displacement has an empty displacement of about 7.5 thousand tons and deadweight 2.5 thousand tons.

The ratio of the power plant mass to the total displacement is determined by the ship's speed, the type of engine (diesel, steam turbine, diesel-electric plant, etc.), as well as the type of the ship. An increase in the speed of the vessel with the same type of installation always leads to an increase in engine power and, consequently, to an increase in the named ratios.

Diesel-powered ships have more engine mass than other types of ships. Since the power plant also includes auxiliary mechanisms for the production of electrical energy and power plants for refrigerators, the mass of power plants for passenger, refrigerated and fishing vessels is greater than the mass of plants for conventional cargo ships of the same displacement. So, the mass of the power plant of cargo ships is 5-10%, passenger ships - 10-15%, fishing vessels 15-20%, and tugs and icebreakers, as a rule, even 20-30% of the total displacement.

The ratio of the mass of the ship's hull to the displacement is determined by the mass of the bare hull of the ship and the mass of its equipment. All these masses depend on the type of vessel and, therefore, on its purpose. The mass of a ship's hull is influenced not only by its main dimensions and their ratios, but also by the volume of superstructures and ice reinforcements. The recruitment system and the use of high-strength structural steels also play a significant role, especially for ships over 160 m in length.

The weight of the equipment depends on the purpose of the vessel; for example, in passenger ships due to passenger cabins, public, utility rooms, etc. or in fishing vessels (fishing and processing) due to crew cabins, fish processing machines and refrigeration equipment, it is significantly higher than that of conventional cargo ships and tankers.

The ratio of deadweight to full displacement (coefficient of utilization of displacement by deadweight) best characterizes the economy of cargo ships (apart from the speed of the vessel). For tugs and icebreakers, the deadweight is primarily determined by the cruising range (duration of the voyage), since in these types of vessels the deadweight is mainly spent on fuel materials and supplies.

Cargo ships and tankers have the highest utilization rate in terms of deadweight (from 60 to 70%), the smallest - tugs and icebreakers (from 10 to 30%).

4.4.4 Features of the shape of the ship's hull

The shape of the ship's hull is determined by its type and purpose. Deadweight, required volume of holds, number of decks, speed and lateral stability have a significant influence on the shape. In addition, the hull shape can be influenced by limitations in length, height and draft associated with the size of locks and bridge spans, with the depth of fairways, as well as the need to solve special problems (for example, towing or icebreaking operations).

The shape of the underwater part of the hull up to the design waterline is determined by the ratios of the main dimensions and the coefficients of completeness, and a compromise solution is often inevitable. So, for cargo ships, it is usually not the completeness factors that are necessary to obtain the minimum power of the main engines and fuel reserves, but higher completeness factors in order to obtain a higher carrying capacity. Only for high-speed cargo ships (for example, refrigerated ships) small, that is, favorable, completeness coefficients, taking into account their speed qualities, are accepted.

Typically, the shape of the vessel is chosen as follows. The constructive waterline forms an angle at the bow with the diametral plane, the value of which, depending on the completeness of the vessel, is 10-25 °. At the aft end, this angle is taken to avoid separation of vortices, 18-20 °. In the stern below the structural waterline, for twin-screw vessels, the frames are given a V-shape, and for single-screw vessels, U-shaped, in order to obtain the most favorable flow conditions in the area of ​​the propeller. In the area of ​​the cruising stern, the frames are made of such a shape that they do not cross the structural waterline very flat, so that with a slight increase in draft (with a differential at the stern) the waterline does not become too full and the resistance to movement does not increase very much. Above the cargo waterline, the frames at the ends of the ship are usually made with camber in order to obtain the maximum buoyancy reserve for reducing the keel net, reflecting the waves flooding the deck and increasing the deck area at the ends of the ship.
Cruising feed: a- single-rotor vessel, b- twin-screw vessel

The shape of the fore and stern posts largely determines the general appearance of the vessel. However, the shape of the extremities is chosen not only from an aesthetic point of view, but also from the point of view of the resistance of the vessel (bulbous bow). The purpose of the vessel also plays a role; for icebreakers, for example, special icebreaker rods have been created, which allow the vessel with all the weight of the bow end to lie on the surface of the ice and break it. For this, the breaking of the stem waterline should be convex, and the entry angle should not be too large. so that the ice floes can freely retreat back. The fillets of the propeller shafts in twin-propeller ships are shaped so that the incoming flow hits the propeller against the direction of its rotation. Therefore, they are not installed vertically to the frames, but, starting at an angle of 90 °, towards the end they descend to the horizontal at an angle of approximately 25 °. Based on practical experience and model tests, several types of contour shapes have been created that meet the requirements for carrying capacity, speed, stability and seaworthiness. For large and series-built ships, model tests are usually carried out to match engine power to speed.

4.4.5 Shipping units

Due to the important role of the English-speaking countries in shipbuilding and shipping, which has survived to this day, in practice and in special literature, along with the international system of units, Anglo-Saxon basic units are also used so far.

Simultaneously with the nautical mile in navigation, the nautical mile is used to determine the position of the vessel at sea and to measure the speed: 1 nautical mile = 1/60 of the meridian degree = 1852.01 m.

This unit will be obtained if you take two straight lines going out from the center of the Earth with an opening angle of 1 minute = 1/60 degrees, and measure the distance between them along the perimeter of the Earth (a large circle). Since the circle contains 360 degrees = 21600 minutes, then, therefore, a nautical mile is equal to 1/21600 of the circumference of the Earth, which is approximately 40,000 km. From the unit of length 1 NM by correlating it with the unit of time 1 hour, the speed in knots (knots) is derived: 1 knot = 1 NM / h = 1.852 km / h.

The units of area and volume are derived from these units of length. 1 register ton is the basic unit used to measure the tonnage of a ship.

Units of mass play a significant role in determining the amount of cargo; in international commodity exchange, in addition to the generally accepted ones, the following English units of mass are also used:

1 long ton = 20 long quintals = 80 long quarters = 160 ston = 2240 pounds = 1,016.047,038 kg

1 lb (lb) - 0.454 kg

1 groan = 6.350 kg

1 long quarter = 12.701 kg

1 long centner = 50.802 kg

Along with the English units of mass, American units are used, which are the same as the English ones. However, when concluding freight contracts, a distinction is made between:

Metric ton (t) = 1000 kg - for sea transport between German, Scandinavian, Dutch, Belgian, French and other ports, i.e. between countries in which the metric system is adopted;

British ton - long ton = 1016 kg - for sea transport from Great Britain and Great Britain (however, metric tons are also used);

North American ton - short ton = 907 kg - if we are talking about the North American region.

Gross tonnage (deadweight) is obtained from the total displacement of the vessel minus the unladen weight of the vessel ready for operation. The carrying capacity of a ship is thus expressed by the mass of cargo that an empty, ready-to-operate ship up to the summer load line can take on board. The payload of the vessel is obtained by subtracting from the total carrying capacity (deadweight) the masses of such components as:

Crew and passengers with belongings or luggage;

Fuel and lubricant supplies;

Provisions and fresh water (water for powering boilers, washing and drinking water);

Boatswain stores, machinery stores and packing materials.

Thus, the payload is a value that depends on the mass of production materials (fuel and water), that is, on the cruising range of the vessel. For cargo ships, the payload is approximately 90% of the carrying capacity (deadweight).

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, which will be discussed in the next section.

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).

4.4.6 Measurement of ships

To determine the size, the vessel is measured. In 1854, after the introduction of the method of measurement by D. Moorsom in England, the size of the vessel began to be determined using the measure of internal space. Measure in 100 cubic meters. feet is called "ton" (barrel); hence, since the measurement results are entered in the ship register, a register ton has arisen: 1 reg. t = 100 cubic meters ft = 2.83 m3.

The ton as a measure of volume has been used since the days of the Hansa trade union, when the size of the vessel (cargo capacity) was determined by the number of barrels that fit in the holds. Carrying capacity or displacement were not considered suitable measures for determining the size of a vessel at the time.

Since then, the measurement method according to Mursov (sometimes with significant deviations) has been the basis for drawing up the Measurement Rules for many states and joint-stock companies operating the channels through which sea transportation is carried out, as well as for drawing up international Rules for the measurement of ships.

Measurement of a ship is an administrative act that is carried out by special state bodies and is formalized by drawing up an official document - a tonnage certificate, which indicates the gross tonnage (gross), net tonnage (net) and the dimensions of the vessel's identity.

The measurement results are for commercial and statistical purposes. In accordance with them, laws are established on the payment of port and pilotage duties, duties for the passage of canals and on the payment of other taxes, crews are recruited for ships and statistical accounting of the gross register tonnage of the merchant fleet of the respective country. In addition, the measurement data is important for the technical equipment of the ship with emergency equipment, steering and other devices, fire-fighting equipment, telegraph, radio and direction finding installations, etc. etc.

In a number of countries, the international Rules for the Measurement of Sea-Going Ships are applied in accordance with the Agreement on a Unified System for the Measurement of Ships, concluded on June 10, 1947 in Oslo. As a result of this measurement, an international tonnage certificate is drawn up, which is recognized by all countries - parties to the agreement without additional verification. Along with the international tonnage certificate, there are also national tonnage certificates and tonnage certificates for the passage through the Suez and Panama Canals. According to the international measurement system, gross tonnage is determined and, by means of certain deductions, net tonnage.

Gross tonnage(ВРТ) is the total capacity of all waterproof 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 measuring deck on ships with no more than two decks is the uppermost deck, and on ships with three or more decks, the second from the bottom.
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 in which there are 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.);

Premises for protecting people at the helm;

Rooms for galleys and bakeries;

Skylights, light shafts and shafts that supply light and air to the rooms below them;

Gates and vestibules that protect gangways, gangways or gangways leading to the premises below;

Bathrooms for the crew and passengers;

Ballast water tanks.

To limit the gross tonnage of double and multi-deck ships, all so-called open spaces are excluded from the gross tonnage. This may include the spaces between the upper deck and the shelter deck (“shelter deck”) and other superstructures if they are made open by measuring hatches in the upper deck or measuring holes in bulkheads. In order to be able to exclude from the measurement of the room below the upper continuous deck, it is necessary by means of the measurement hatch to create the so-called measurement space, from which the adjacent compartments can be made open using the measurement holes. Only loosely laid wooden beams can be used as closures for measuring hatches; U-shaped metal strips or sheets held by L-shaped bolts can be used as closures for measuring holes in bulkheads.

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 the measurement is that they do not serve to accommodate or serve the crew and passengers. If the upper decks of double or multi-deck ships and the bulkheads of superstructures are fitted with strong watertight closures, the interdeck space below the upper deck and the spaces of superstructures are included in the gross tonnage. Such vessels are called full-range vessels and have a maximum allowable draft.

Net tonnage(NRT) is the useful volume for accommodating passengers and cargo, i.e. the commercial volume. It is formed by subtracting the following components from the gross tonnage:

Premises for the crew and navigators;

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 calculated length (identical) is the length along the uppermost continuous deck from the trailing edge of the stem to the middle of the stock, and in ships with a hinged rudder

To the trailing edge of the sternpost.

Calculated width (width of identity) - the width of the vessel at its widest part. Design draft (identity draft) - the distance between the lower edge of the uppermost continuous deck and the upper edge of the deck of the second bottom or floras in the middle of the design length.

Economic considerations led to the creation of a shelter boat, as "open" spaces, as mentioned above, are not included in the gross tonnage. But since the prescribed by the rules for closing the measuring holes of the shelterdeck or other "open" spaces reduce the reliability of ships, such volumes under the Load Line Rules should not be taken into account when calculating the freeboard - the buoyancy margin of the ship. Until the introduction of an international uniform system for measuring ships in the Measuring Rules, which are currently in force on the recommendation of the Intergovernmental Maritime Consultative Organization (IMCO) dated October 18, 1963, by introducing a tonnage mark, the advantage of open spaces should be retained, despite the waterproof closures of the shelf and other spaces. The principle underlying the recommendations for the introduction of the tonnage mark is that certain spaces in a twindeck that are considered open and therefore not included in the gross tonnage may be closed for some time, and such spaces are considered isolated if the tonnage mark , located below the second deck on the sides of the vessel, when the vessel is loaded, it lies not below the waterline. Spaces that are suitable for allocation and are located in free-standing superstructures or wheelhouses on or above the upper continuous deck, despite strong watertight closures, should be excluded from the gross tonnage, regardless of whether the tonnage mark is loaded or not.
Load lines: 1 - tonnage line, 2 - load line

Tonnage (measurement) mark is applied on each side of the vessel aft of the freeboard mark. In no case should the tonnage mark be applied above the load line - the freeboard mark. The additional line for freshwater in tropical waters is generally given minus 1/48 of the draft above the topside of the keel to the sizing mark. In case the tonnage mark (the upper edge of the horizontal line) is not submerged, the gross and net tonnage of the premises located inside the upper twin deck and suitable for allocation are used for commercial purposes.

Hull

The hull of the ship is a box-shaped girder with thin walls and reinforcements, which at the ends at a more or less acute angle passes into the fore and stern post. The side siding and all continuous longitudinal bulkheads form the walls of this box girder.

The bottom flooring (including the zygomatic girdle), the flooring of the second bottom and all longitudinal ties passing through the double or single bottom form the lower belt of the box girder "ship", and the continuous deck flooring next to the hatches and continuous longitudinal ties of the main deck, as well as the shirstrek ( the uppermost belt of the side sheathing sheets) is the upper one. The upper and lower belts take up the normal tensile and compressive stresses from the buckling of the vessel.

Internal reinforcements are beams that are parallel and perpendicular to the center plane of the vessel (longitudinal and transverse sets). They serve for the perception and transmission of local loads (hydrostatic and hydrodynamic pressures, load pressure) and for stiffening the upper and lower belts, and also protect the outer skin from deformation.

The hull is divided by decks in height. The sides, bottom and decks of the ship converge at the extremities and end with fore and stern posts. Watertight bulkheads divide the hull into watertight compartments and reinforce it like a transverse set. On the uppermost continuous deck - the main deck - are the superstructures and deckhouses. Long superstructures in the middle section are included in the upper belt of the ship's hull.

Longitudinal, lateral and torsional loads on the hull are absorbed due to the appropriate positioning and execution of the ship floors. Overlapping steel vessels consist of sheets and profiles.

Usually, a ship's hull is distinguished by bottom, side and deck overlaps, pins and bulkheads. In addition, there are structural connections of superstructures, deckhouses and other parts of the ship's hull, such as foundations, propeller shaft tunnel, hatches, and shafts.
Structural elements and connections of the ship's hull: a - afterpeak bulkhead, b - box girder, c - superstructure, d - bow end, e - stern end, f - cargo hatch area, g - area between cargo hatches, h - engine room area, i - main deck in the area of ​​the cargo hatch corner 1 - afterpeak tank deck; 2 - stern tube; 3 - upper sheathing belt; 4 - wall; 5 - the lower belt of the sheathing; 6 - deck flooring; 7 - longitudinal coaming of the hatch; 8 - cross hatch coaming; 9 - shirstrek; 11 - zygomatic girdle; 12 - flooring of the second bottom; 13 - bottom plating; 14 - chain box; 15 - twin deck; 16 - collision bulkhead; 17 - yut; 18 - emergency exit; 19 - afterpeak; 20 - propeller shaft; 21 - stern tube; 22 - stern post; 23 - rudder feather; 24 - rudder stock; 25 - tank; 26 - forepeak; 27 - side stringer; 28 - twin frame; 29 - hold frame; 30 - upper (main) deck; 31 - propeller shaft tunnel; 32 - carlings; 33 - bottom stringers; 34 - vertical keel; 35 - machine shaft; 36 - upper skylight; 37 - navigation bridge; 38 - boat deck; 39 - middle superstructure deck; 40 - upper (main) deck; 41 - the foundation of the main engine; 42 - superstructure frame; 43 - extreme double bottom leaf; 44 - frame beams; 45 - frame frame; 46 — rhomboidal sheet-overlay; 47 - pillers; 48 - nasal breasts; 49 - longitudinal rib.

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5.1.1 Structural elements of the ship bottom

For bottom floors, two fundamentally different options are distinguished, namely single and double bottom.

As a rule, small vessels with a length of less than 60 m have a single bottom, and above all vessels with a strong rise of the cheekbones and a squared keel. Floras with frames, into which they pass, form a continuous transverse set. Longitudinal bonds in the area of ​​the bottom, the so-called keelsons, protect the flora from buckling. The most important longitudinal bond of a single bottom is the middle keelson, which, along with reinforcing the flora and strengthening the keel (which is important when docking), increases the longitudinal strength of the vessel.

There are three options for performing the middle keelson:

Average keelson standing on floras - for ships shorter than 30 m

Inter-bed keelson

Medium keelson in the form of a medium keel sheet

In small vessels, the flora in the diametrical plane is usually not cut. For longer vessels, a continuous bottom keelson is preferred for better longitudinal load absorption. Depending on the width of the vessel, one or two bottom stringers are installed on each side, the purpose of which is the same as for the middle keelson. The distance between the bottom stringers and the middle keelson and their distance from the sides of the vessel is no more than 2.25 m; in the bow end, due to the strong load on the bottom during pitching, they are installed at a smaller distance from each other. Floras consist of sheets reinforced with vertical stiffeners, running across the entire beam of the vessel and interrupting only on a continuous middle keelson. At the ends of the ship, in the fore and afterpeak, the floras are higher, in the afterpeak they reach a level above the stern tube. The single bottom between the ram and afterpeak bulkheads (with the exception of the engine room) is covered with a wooden deck. In the area of ​​the engine room, the simple bottom is covered with bottom sheets (fir trees), usually of corrugated sheets.

With a double bottom, there is also a second waterproof bottom above the longitudinal and transverse ties located on the bottom belts of the outer skin. The double bottom is designed to resemble a flat box girder. Cross-links at the double bottom also consist of floras. A double bottom has the following advantages over a single bottom.

1. Increases the strength of the vessel when grounding; with a leak in the double bottom area, buoyancy is retained, since water can penetrate only to the floor of the second bottom. For this reason, the requirements of the International Convention for the Safety of Life at Sea require small passenger ships to have a second bottom in the bow end from the engine room bulkhead to the collision bulkhead, and large passenger ships (over 76 m in length) - from the afterpeak bulkhead to the collision bulkhead.

2. By waterproof longitudinal and transverse ties, the double bottom is divided into tanks for storage of liquid fuel, fuel oil and lubricating oil, washing, feed and ballast water.

On the other hand, the double bottom increases the dead weight of the vessel and increases the construction cost. Therefore, on small ships, it is abandoned or installed only in the area of ​​the engine room for fuel and lubricating oil tanks. The vertical keel serves not only to increase the longitudinal strength of the vessel and as the main support during docking, but also to increase the rigidity of the bottom between two bulkheads, as well as to prevent deformation of the floras. The keel runs from stern to bow through the entire vessel. In the middle of the length of the vessel, it is made watertight in order to divide the double bottom in width and to reduce the free surface in double bottom tanks. At the extremities, where, due to the small width of the vessel, the tanks pass from side to side, the vertical keel is equipped with facilitating cutouts (manholes). Depending on the width of the vessel, one, two or more interbody bottom stringers are located on either side of the vertical keel, which perform the same tasks as the vertical keel.

To reduce the weight of the vessel and make the double bottom accessible, cutouts are provided in the bottom stringers, if they do not serve to separate the vessel from water and oil. The flooring of the second bottom together with the outer double bottom sheets forms the bottom overlap. The extreme double bottom leaf is either located obliquely to the flooring of the second bottom and approximately at right angles to the cheekbone, or lies in the plane of the second bottom. For access to the double bottom, a closing hatch is made in the deck at the end of each of its compartments. The transition from floras to side frames at the extreme double bottom sheets is carried out with the help of the cheekbones, and for the horizontal extreme double bottom sheets - with the help of the knits.

Floras are located in a double bottom at right angles to the center plane of the vessel. As a rule, they run from the vertical keel to the outer double bottom leaf. In this case, three types of flora should be distinguished. The watertight flora form the limitation of double bottom tanks, and their function can be compared to watertight transverse bulkheads. With a high double bottom height (over 0.9 m), they are reinforced with vertical stiffeners. Solid flora is similar to waterproof. Since they do not need to be watertight or oiltight, cutouts are provided in them to reduce their own weight and to make separate double bottom compartments accessible. Solid flora, depending on the length of the vessel, are placed in the bow at every third or fourth frame; on ships for the transport of heavy cargo, under engine rooms, as well as under transverse bulkheads, heavy and end pillars of middle diametrical bulkheads - on each frame. Open brace floras are placed on frames, which do not need waterproof or solid floras. They consist of rolled profiles, which are installed on the bottom skin (bottom corner of flora) and on the flooring of the second bottom (top corner of flora). Brackets are used to connect floras with a vertical keel, bottom stringers, and an extreme double bottom leaf.


Double bottom: a - split double bottom; b - double bottom with solid and brace floras; c - double bottom with a longitudinal set (with longitudinal stiffeners); d - double bottom with bottom stringers. 1 - ballast water (forepeak); 2 - ballast water (double bottom); 3 - fuel; 4 - lubricating oil; 5 - rubber dam; 6 - fresh water; 7 - shelf of the cheekbone; 8 - flooring of the second bottom; 9 - waterproof floor; 10 - open bracketed floor; 11 - flora top square; 12 - bottom square of flora; 13 - brackets; 14 - continuous flora; 15 - horizontal keel; 16 - vertical keel; 17 - side stringer; 18 - zygomatic stringer; 19 - cheekbone; 20 - hold frames; 21 - cheekbone; 22 - bottom longitudinal beams; 23 - longitudinal beams of the second bottom; 24 - extreme double bottom leaf; 25 - bottom stringers.

At present, instead of permeable ones, usually continuous flora with enlarged cutouts are installed. The production and assembly of solid floras is easier than bracket floras; at the same time, when in contact with the ground, solid floras reduce the deformations of the bottom structures; in addition, solid flora is only slightly heavier than bracketed ones. Zygomatic brackets, or knits, connect the hold frames with the extreme double bottom sheet or the second bottom, i.e., with the bottom cross-links, and reinforce the cheekbone. To reduce weight and for laying pipelines, the cheekbones are provided with cutouts. The free edge of the zygomatic brackets is folded over or supplied with a belt or horizontal knit. Horizontal knits serve to reinforce the transverse set interrupted by the extreme double bottom leaf and to create an effective transition from the zygomatic knit to the flooring of the second bottom and thus to the bottom floras or brackets.

Along with the traditional method of building a second bottom with bracketed or solid floras on each frame, in recent decades, the construction method with longitudinal stiffeners has been increasingly used, and for large ships (over 140 m in length) - with bottom stringers. The advantage of the longitudinal stacking system is that it significantly increases the longitudinal strength of the bottom. Bottom longitudinal stiffeners or stringers together with the skin perceive the bending stresses of the ship's hull (tension and compression), as well as local loads, arising in the bottom. A double bottom with longitudinal stiffeners or stringers with the same strength is lighter than a double bottom with floras on each frame. The disadvantage is that the process of making ships in this way is more laborious (especially when bending stiffeners for the extremities) and, therefore, more expensive.

With a longitudinal recruitment system, continuous floras are placed on every third or fourth frame, that is, at a distance of approximately 3.6 m from one another; only in the area of ​​the bow of the vessel and under the foundations of the main engines are these distances smaller. The distance of the bottom stringers from each other or from the vertical keel and the outer double bottom leaf is approximately 4.5 m; they are smaller in the area of ​​the bow and under the engine room. Brackets are placed between the floras at the extreme double bottom leaf, and at the bottom stringers - vertical stiffeners at a distance of spacing; at the vertical keel, depending on the distance between the floras, one or two brackets with flanges are additionally placed on both sides. The bottom stiffening ribs, which, depending on the size of the vessel, are set at a distance of 0.7-1 m, pass through the solid flora. With a longitudinal set system with stringers, elliptical or arched cuts are made in the latter.

5.1.2 Exterior casing and side kit

The outer shell is the shell of the ship's hull; it must perceive the pressure of water and at the same time, as part of the longitudinal set, together with other longitudinal ties, ensure the longitudinal strength of the ship's hull. The outer skin consists of individual sheets, which are welded to each other, with frames, decks and bottom braces. The length of the cladding sheets is usually considerably longer than the width. The vertical joint line (weld seam) of the sheets is called a joint, and a more or less horizontal joint line is called a groove. The grooves form harmonious curves along the length of the ship. The sheathing belts that run between these so-called curved curves are called singing. Each belt is named according to its position on the ship's hull. The appendages of sheets that adjoin directly to the keel are called keel, the rest are singing, and also chanting next to the horizontal keel in the flat part of the bottom - bottom. The belt of sheets, which covers the rounding of the cheekbones, is called the zygomatic girdle, the singing of the leaves from the flora above the zygomatic girdle is the side chanting, the uppermost one is the shirstrek. The number of joints and seams depends on the size of the sheets. Depending on the size of the vessel, the width of the sheets is from 1.2 to 2.8 m, and the length is from 5 to 10 m. Smaller sheets are installed at the ends of the vessel, since volumetric bending and installation of large sheets would be too laborious. The thickness of the outer skin depends on the length of the vessel, the height of the side to the upper continuous deck, as well as on the draft and the distance between the frames (spacing). This thickness is about 5 mm for vessels with a length of 20 m and about 25 mm for vessels with a length of 250 m. But even for the same ship, the thickness of the outer skin is not the same everywhere. So, during waves, the ship experiences the greatest bending stresses in the middle part, therefore the sheets are thicker there than in the extremities. As a rule, shirstrek and horizontal keel are also made thicker than other puffing sheets, because they are important longitudinal ties and are additionally subject to loads acting on the lateral ties. The horizontal keel experiences large compressive loads when docking, therefore the bottom ones are thicker than the side ones.

Outer sheathing:
1 - shirstrek, 2 - bulwark, 3 - leaf stem, 4 - seam, 5 - leaf belt, 6 - leaf joints, 7 - zygomatic belt, 8 - side belt, 9 - bottom singing, 10 - horizontal keel, 11 - area reinforcements, 12 - superstructure side plating

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The singing of the outer skin sheets in the area of ​​transition to the superstructure are also reinforced, since there is a particularly high concentration of stresses during bending of the vessel in waves. Due to pitching, in addition to the bottom set in the bow and stern ends, the outer skin is also reinforced. Ice-reinforced vessels have thickened side skin, especially if they are built in accordance with the Rules for a higher ice class and to operate in Arctic waters. Ice reinforcements have not only the outer skin, but also onboard communications - frames and stringers, as well as the head and stern post, steering gear and individual parts of the power plant, such as the propeller, shaft line and engine crankshaft.

Frames are the ribs of the ship's hull, which are located in vertical planes and give the ship its shape. They are a continuation of the transverse connections of the bottom of the ship and form a frame frame with the bottom floras, cheekbones or brackets, beams and beams, open in the area of ​​hatches and closed outside the hatches and shafts. Frames, together with other transverse ties, must provide local strength of the hull so that the vessel can absorb the loads acting on it from the pressure of water, ice and cargo. In conjunction with the transverse bulkheads, the frames also increase the longitudinal strength of the vessel, preventing deformation of the outer skin. Frames are distributed along the entire length of the vessel (excluding extremities) at equal distances from each other. This distance, depending on the length of the vessel, ranges from 0.5 to 0.9 m. As a rule, frames are numbered from the forward perpendicular to the stern, starting from "0"; frames behind the aft perpendicular are numbered negative. The load on the frames increases downward from the surface of the water in accordance with the increase in hydrostatic pressure. Therefore, their cross-sections are maximum in the area between the bottom and the lowest deck; they gradually decrease from deck to deck. The dimensions of the hold frames depend on the size of the vessel, on the draft and on the height of the bilge brackets. Typical end attachments of hold frames to beams are shown in the figure. In ships with a single bottom or with a horizontal flooring of the second bottom, the hold frames at the outer skin are connected with the floras in the back, so that the connection is sufficiently rigid for bending; sometimes they are attached with knits. The dimensions of the twin deck frames also depend on the size of the vessel, that is, from the side depth to the main deck, from the height of the twin deck, the number and position of the twin deck, from the draft and spacing. Typical end attachments for intermediate frames to decks and beams are shown in the figure. The dimensions of the superstructure frames and their end fixings are determined in the same way as for twin deck frames.

Frames and side kit:
a - the location of the frames (side view); b - connection of the side of the vessel with a single bottom; With - onboard set of a single-deck vessel in the area of ​​the cargo hatch; d - onboard set of a three-deck vessel; e - onboard set in the area of ​​the engine room; f - a set of cruising stern.
1 - twin-deck frames; 2 - knits; 3 - hold frames; 4 - shelf of the cheekbone; 5 - cheekbone; 6 - beams; 7 - transom sheet; 8 - aft frames; 9 - sternpost; 10 - longitudinal coaming; M - transverse coaming; 12 - frame beams; 13 - frame frame; 14 - side stringer; 15 - intermediate deck; 16 - bottom flora; 17 - medium keelson; 18 - connection of the frame with the floor.

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In those areas of the ship's hull where particularly high stresses arise or where the ship's hull must be especially rigid (for example, in the engine room area), reinforced frame profiles are installed in the area of ​​large hatches - the so-called frame frames. They consist of walls with welded shelves. At the ends of large cargo hatches, frame frames, together with hatch end beams and hatch transverse coaming, form a closed frame of great rigidity and strength.

In the stern (at cruising stern), the frames are located in planes that are not vertical to the diametrical plane, since otherwise the walls of the frames would stand too inclined to the outer skin and would significantly reduce its strength. Therefore, the aft frames are located in planes that are located at different angles to the center plane and almost vertical to the outer skin. Together with appropriately positioned beams, they form separate frames, which are attached to the so-called transom plate. A transom plate is a reinforced plate located at right angles to the longitudinal axis of the vessel. It connects to the sternpost and replaces the flora in this place.

To reinforce the frames, side stringers are installed in the bow and stern ends. The forepeak and afterpeak under the lowest deck are additionally reinforced with frame stringers. If the forepeak and afterpeak are designed as tanks, then additional stringers are installed between the frame stringers at half the distance. For ships with ice reinforcements, additional frames are installed; for ships with smaller ice reinforcements, they are limited to the bow; for vessels of a higher ice class, additional frames and stringers are installed along the entire length of the vessel. In the area of ​​ice reinforcements, the outer skin can withstand ice pressure up to 784.8 kPa.

Onboard bow tip kit:
1 - main deck, 2 - side stringer, 3 - stem, 4 - reinforced side stringer, 5 - flora, 6 - beams, 7 - collision bulkhead, 8 - double bottom, 9 - hold frames, 10 - tank bulkhead

Decks and below deck set

Decks are slabs in the ship's hull that run almost horizontally. The uppermost continuous deck - the main deck - covers the ship's hull from above and forms, alone or with the deck of a long superstructure, the upper hull shell. The decks below the main deck have the task of increasing the useful area of ​​the vessel to accommodate passengers and cargo. Decks above the main deck are called superstructure decks.

The vertical distance between the decks, on which the crew and passengers are accommodated, is from 2.2 to 2.8 m.The height between the cargo decks is from 2.5 to 3.5 m, and the height of the cargo spaces lying under the lowest deck is 6 m and more. The thickness of the main deck planking depends on the length of the vessel, from the depth to the main deck, the height of the twin deck, the draft, the set system (longitudinal or transverse) and the distance between the beams, as well as the width of the continuous deck between the cargo hatches and the outer skin. In this case, the thickness of the deck flooring varies depending on the magnitude of local loads acting on the ship's hull: in the middle of the ship they are greatest, and to the extremities they become smaller. In addition, the deck sheaths between hatches are generally considerably thinner than the sheaths between hatches and outer skin. The thickness of the sheets on the main deck ranges from 5 to 30 mm, depending on the length of the vessel. The corners of the hatches are sheathed with reinforced or doubled sheets to avoid rupture of the deck flooring due to stress concentration.

The planking of the lower decks has a slightly smaller thickness, which depends on the load and on the distance between the beams and is about 5 mm for small ships, and rarely exceeds 1 2 mm for large ships. Deck flooring, like the outer skin, is made of separate sucking sheets, and the chanting ones lying at the shirstrek are called deck stringers, and the chanting ones passing along the hatches are hatch stringers.

To the deck stringers, all singing sheets run parallel to the center line. Deck stringers taper at the ends of the vessel and end in sheets across the vessel. In the middle of the ship, the main deck deck stringers are sometimes riveted using a stringer square with the outer plating of the ship (with a shirstrek).

Beams passing across the vessel with the longitudinal set system carry the deck flooring and the load lying on the deck. They are reinforced with longitudinal under-deck beams and pillers in one or more places along the width of the ship. The longitudinal under-deck beams pass through and rest on the frame beams. The dimensions of the beams depend on the load on the deck, the span length and the distance between the beams; in addition, the beams of the main deck in the middle of the ship should have a minimum stiffness (moment of inertia), which depends on the thickness of the main deck, in order to protect the deck flooring from deformation under compressive stresses. Deck beams are connected with frames with knits. The beams, interrupted by access hatches or other cutouts, are reinforced by carlings (longitudinal beams) that are attached to reinforced deck beams.

The longitudinal underdecks are made of welded profiles. In places where the beams pass, they are provided with cutouts in accordance with the profile of the beams. The tee profiles are protected from deformations and displacements by brackets. The longitudinal underdeck beams are usually attached to the transverse bulkheads by means of knits. The dimensions of the longitudinal beams depend on the load on the deck and on the span and width of the slab to which the load is applied. The pillers run from the floras or flooring of the second bottom to the uppermost deck; on separate decks, they stand exactly one above the other, since otherwise the beams would receive additional bending load. Pillers are made from steel pipes (less often from squares) or other rolled sections. At the ends they have heel plates and top plates, and on both sides of the longitudinal beam wall there are vertical brackets, which serve to reliably transfer the deck pressure and beams to the pillers and prevent lateral displacement of the longitudinal beam. The cross-sections of the pillars are determined by the load and length.

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Decks: a - the names of the decks; b - deck with a transverse set system; With - deck with longitudinal set system.

1 - deck poop; 2 - main deck (bulkhead deck and freeboard deck); 3 - second deck; 4 - propeller shaft tunnel; 5 - navigation bridge; 6 - command bridge; 7 - boat deck; 8 - middle superstructure deck; 9 - bottom skin; 10 - tank deck; 11 - third deck; 12 - flooring of the second bottom; 13 - seams; 14 - cargo hatches; 15 - joint; 16 - hatch reinforcements; 17 - machine shaft; 18 - deck stringer; 19 - beams; 20 - carlings; 21 - diamond-shaped sheet; 22 - frame beams; 23 - hatch stringers; 24 - deck planking (deck and hatch stringers next to the side and hatches); 25 - flooring between hatches; 26 - longitudinal underdeck beams; 27 - frame beams; 28 - corrugated bulkhead.

Bulkheads and tanks

A bulkhead is understood to be a water- and dust-proof vertical wall installed in the ship's hull. Longitudinal and transverse bulkheads are distinguished according to the position relative to the ship's DP. Watertight bulkheads divide the ship into watertight compartments; in passenger ships, they are located so that when one or more adjacent compartments are flooded, the ship's buoyancy is preserved. Transverse bulkheads increase the transverse strength and, by preventing buckling of the sides and floors, the longitudinal strength of the vessel. Watertight and oiltight longitudinal bulkheads are only installed on ore carriers and tankers.

The number of watertight bulkheads depends on the length and type of ship. On each ship, an emergency collision bulkhead is provided behind the stem. In propeller driven ships, an afterpeak bulkhead is installed at the stern end, which usually limits the afterpeak. Steamships and motor ships have one transverse bulkhead at the ends of the engine and boiler rooms. The rest of the hull, in accordance with the length of the vessel, is divided by other transverse bulkheads, the distance between which does not exceed 30 m. The collision bulkhead in ships with a solid superstructure or a tank extends from the bottom to the deck of the superstructure or tank, while the afterpeak bulkhead usually only reaches the watertight deck above the summer load waterline.

Watertight transverse bulkheads:
a - location of bulkheads at a cargo ship (full-load vessel); b - transverse bulkhead; With - corrugated bulkhead; d - collision bulkhead.
1 - yut; 2 - afterpeak; 3 - afterpeak bulkhead; 4 - holds; 5 - middle superstructure; 6 - bulkhead deck; 7 - engine room; 8 - lower deck; 9 - tank; 10 - chain box; 11 - forepeak; 12 - collision bulkhead; 13 - double bottom; 14 - propeller shaft tunnel; 15 - knits; 16 - singing bulkhead skin.

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§ 6. Ratios of the main dimensions and coefficients characterizing the shape of the ship's hull

In addition to the previously given general information about the shape of the contours of the center line, the constructive waterline and the mid-frame, for a more complete characterization of the shape of the ship's hulls and an idea of ​​the seaworthiness and operational qualities of ships that depend on it, it is necessary to know the following numerical ratios of the main dimensions of the ship:

1) the L / B ratio, which affects the running of the vessel;

2) the ratio V / H, which affects the stability of the vessel, its speed and pitch. Increasing the relative width improves the stability of the vessel, but the roll becomes sharper and the resistance of the water to the movement of the vessel increases;

3) the ratio Н / Т, which affects the unsinkability of the vessel. Increasing the relative depth improves the unsinkability of the vessel;

4) the ratio L / T, which affects the turnability of the vessel. An increase in the relative length of the vessel impairs its turnability;

5) the L / H ratio associated with the characteristic of the general longitudinal strength of the vessel (according to the Rules of the USSR Register, L / H should be in the range from 9 to 14).

Finally, the dimensionless completeness coefficients obtained by comparing the main areas and volumes of the hull with the corresponding areas and volumes of the simplest geometric figures and bodies built on its main dimensions allow us to judge the shape of the underwater part of the ship's hull.

These main factors of completeness of the underwater part of the ship's hull are:

A) the coefficient of completeness of the structural (cargo) waterline a - the ratio of the area of ​​the waterline 5 to the area of ​​the circumscribed rectangle, built according to the calculated length L and the width of the hull B (Fig. 8, a)


b) the coefficient of completeness of the mid-frame c is the ratio of the area of ​​the immersed part of the mid-frame w to the area of ​​the circumscribed rectangle built according to the calculated width B and the draft of the hull T (Fig. 8, b)



Rice. 8. Coefficients of completeness of the underwater part of the ship's hull: a - waterline; b - midship frame; в - displacement.


c) coefficient of displacement completeness B - the ratio of the volume of the underwater part of the hull V to the volume of the described parallelepiped, built on the calculated length L, width B and draft of the hull T (Fig. 8, c)


In addition to the three given basic and independent coefficients a, B and b, two coefficients (f and y) are used, which are derivatives of the first and associated with them by the following ratios:

D) the coefficient of longitudinal completeness f - the ratio of the volume of the underwater part of the vessel V to the volume of the prism with the base equal to the area of ​​the submerged part of the midsection w, and the height equal to the length of the hull L,


Substituting instead of o and V their values, after simplification, we obtain the dependence of this coefficient of the overall completeness and the completeness of the mid-frame


The coefficient f expresses the distribution along the length of the hull of the volume of its submerged part, which affects the resistance of water to the movement of the vessel;

D) the coefficient of vertical completeness y - the ratio of the volume of the underwater part of the hull V to the volume of the prism, the base of which is equal to the area of ​​the structural (cargo) waterline of the vessel S, and the height is the draft of the hull T

 

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