Determination of the cross-section of the pillars for a double-decker vessel. Design of a ship set, concept of a ship, classification of ships, transport ships, service and auxiliary ships, technical fleet ships and special ships, hydrofoil ships What is a saw?

Goal of the work. For a double-deck dry cargo ship, the upper and lower decks of which are loaded with a uniform load, select the cross-sectional dimensions of the pillars based on the conditions of strength and stability.

8.1. Theoretical section

To reduce the load on the main connections of the deck floors of dry cargo ships, pillars are installed in the holds and engine room, which reduce the span of beams and carlings, which makes it possible to reduce their size.

Pillers are installed at the intersection of beams and carlings and are made of pipes with different ends secured. The cross-sectional dimensions of the pillars must satisfy the conditions of strength and stability. The load on each pillar is determined from the condition uniform distribution the total load on the deck floor between all pillars and the supporting contour (sides, transverse bulkheads).

The geometric characteristics of the pillar section are determined by the formulas:

- cross-sectional area ,

– moment of inertia of the section,

where d is the outer diameter of the pipe (pillar),

t – wall thickness.

The distribution diagram of the load on the deck floor between the pillars is shown in Figure 8.1.

Take the safety factor for the pillars as k=0.8. Then the permissible stresses will be equal to

where is the yield strength of the piller material.

The selection of the cross section of the pillar from the stability condition is carried out taking into account deviations from Hooke’s law in the following order:

1) Set the values of the critical stress in fractions of the yield strength, up to which it is necessary to ensure the stability of the pillar.

2) On the graph (Figure 7.1) according to accepted value critical stress determine the corresponding Euler stress.

3) Determine the coefficient characterizing the deviation from Hooke’s law.

4) Calculate the calculated moment of inertia of the pillar cross section using the formula ,

where is the coefficient characterizing the estimated length of the pillar depending on the type of fastening of its ends:

– for free support, both ends,

– for rigid pinching of both ends,

– one end is freely supported, the other is rigidly clamped.

Due to the fact that the cross-sectional area of the pillar F is unknown, the problem is solved by selecting the ratio , as a result of which the cross-sectional area and moment of inertia of the pillar section are finally determined in accordance with current standards. At the same time, the requirements of strength and stability must be met,

where is the compressive stress from the compressive load acting on the pillar.

a) view of the deck; b) section along the bilge frame

Figure 8.1 – Layout of pillars in the hold of a dry cargo ship

8.2. Individual calculation task

When calculating the strength of the pillars of the upper and lower decks, the load on the deck floors is considered uniform, while the density of the cargo on the lower deck is 2 times higher than the density of the cargo on the upper deck.

When calculating the stability, pillars are considered as centrally compressed rods under various conditions for securing the ends. To account for deviations from Hooke's law, use diagram or figure 7.1 of these methodological instructions. The arrangement of pillars and structures in the area of the cargo compartments of a dry cargo ship is shown in Figure 9.1.

The initial data for the calculation should be taken from Table 9.1.

The report must contain a diagram of the location of the pillars in the area of the cargo hold compartment of a dry cargo 2-deck vessel, the distribution of loads on the pillars. Using the initial data, select the dimensions of the pillar sections based on the strength and stability under the action of a compressive load and make a conclusion about their stability.

Table 8.1 – Initial data for calculating pillers

№	Vessel width L, m	Floor length Lп, m	Upper pillars lв, m	Lower pillars lн, m	Steel yield strength, MPa
IN	N
Stanchion
	15,0	11,2	3,0	5,2
	18,0	11,2	3,2	5,4
	21,0	11,2	3,4	5,6
	15,0	12,8	3,0	5,2
	18,0	12,8	3,2	5,4
	21,0	12,8	3,4	5,6
	15,0	14,0	3,0	5,2
	18,0	14,0	3,2	5,4
	21,0	14,0	3,4	5,6
	15,0	9,6	2,8	4,8

8.4. Control questions

1) Define stability, Euler and critical stresses.

2) Determine the main provisions of the Euler method.

3) In what cases are deviations from Hooke’s law taken into account when checking the stability of rods?

4) Indicate practical methods for taking into account deviations from Hooke’s law when calculating the stability of rods.

5) Write the procedure for determining the cross-sectional dimensions of the rods from the stability condition, taking into account deviations from Hooke’s law.

PRACTICAL WORK No. 9

CALCULATION OF PLATES OF THE BOTTOM SKIN OF THE SHIP HULL

Purpose of the work: For the bottom plating of a ship's hull with a transverse framing system, calculate the maximum deflection, as well as bending and total stresses in the plate (in the center and on the long side of the support contour).

9.1. Calculation of plates bending along a cylindrical surface

9.1.1. Theoretical section

Given the aspect ratio of the supporting contour, the bending of a rigid plate under the action of a uniformly distributed load (pressure on the bottom) can be considered cylindrical, and the calculation of such a plate can lead to the calculation of a single beam-strip. To calculate a strip beam, we apply the formulas of the beam theory of bending with the replacement of the normal elastic modulus E by the reduced modulus. Since the plates are subject to longitudinal forces from the general bending of the ship’s hull, the stresses in the beam-strip can be determined using the compound bending formula

where h is the thickness of the plate,

– stresses from the general bending of the body (tensile),

– bending moment in the strip beam (at the support or in the middle),

– Bubnov function, which takes into account the influence of longitudinal forces on the bending moment of the beam-strip and depends on the argument u, equal , (9.1)

a – short side of the plate (length of the beam-plate),

– cylindrical rigidity,

- Poisson's ratio.

The plate is considered to be rigidly clamped on the supporting contour. The moments in the strip beam are equal at the support , in the middle of the flight

, (9.2)

Where R– pressure on the hull of the ship’s bottom during draft d (see table 9.1).

Accept functions according to Table 6.3 of the Directory

9.1.2. Individual calculation task

Take the initial data according to table 9.1.

Table 9.1 – Initial data

Var. No.	, m	, m	, m	, m	, MPa
	0,70	2,00	0,011	7,5
	0,70	1,90	0,011	8,0
	0,80	2,40	0,012	7,5
	0,80	2,20	0,012	8,0
	0,80	2,00	0,012	8,5

9.2. Checking plate strength using reference data

9.2.1. Theoretical section

Rigid plates include plates with an aspect ratio b\h£60, where b is the smaller dimension of the plate contour, h is the thickness of the plate.

The solutions of rigid plates obtained by M. Levy's method are given in tabular form.

The deflection arrow, m, at the center of the plate is determined by the formula

. (9.3)

Linear bending moments are determined at the center of the plate and on the supporting contour according to the formulas

. (9.4)

where , – long and short sides of the supporting contour of the plates, m.;

– coefficients are determined from the table depending on the fixation of the plate on the support contour and the ratio of the sides of the support contour;

– pressure on the plate (in the center), MPa;

– modulus of elasticity, MPa.

Bending stresses in the plate are determined by the formula

9.2.2. Individual calculation task

1) Determine the type of plate.

2) Using the above method, calculate bending moments and stresses, as well as the maximum deflection in the center of the bottom plate at vessel draft d.

The report must contain a calculation of the strength of plates using the method of calculating plates of finite stiffness; with determination of bending moments and shearing forces, as well as the highest values of the deflection arrow and stresses.

9.3. Control questions

1) Define plates, explain the classification of plates according to rigidity and the ratio of the sides of the supporting contour.

2) What is the essence of calculating platinums of final rigidity.

3) Name the classification of plates based on rigidity.

4) Name the classification of plates in relation to the sides of the supporting contour.

5) Describe a method for solving rigid plates.

PRACTICAL WORK No. 10

CALCULATION OF BENDING MOMENTS AND SHEARING FORCES DURING GENERAL BENDING OF THE VESSEL.

DISTRIBUTION OF VESSEL MASSES ACROSS THEORETICAL COMPARTMENTS.

Goal of the work

Distribute the masses of the vessel into theoretical compartments to determine the intensity of the load during the general bending of the vessel.

10.1. Theoretical section

The ship's hull is a box-shaped cross-section beam subject to mass and supporting forces.

To determine the magnitude of bending moments and shear forces, it is necessary to construct a load diagram, which is obtained by algebraically summing the masses and forces supporting water in each section of the ship’s hull. Research has shown that it is advisable and sufficient to divide the length of the vessel into 20 equal sections (theoretical spaces), within each of which the masses are distributed evenly. The rules for mass distribution among compartments are given in.

Based on the calculation results, a step curve of the masses that make up the displacement should be constructed along the length of the vessel.

10.2. Individual calculation task

For the architectural and structural type (AKT) of a vessel developed in a course project in the discipline "Ship Design and floating structures":

a) divide the ship’s hull into compartments in accordance with the requirements of the Register Rules, as well as into 20 equal-sized compartments;

b) distribute the masses of the metal body in the form of a trapezoid;

c) distribute the main load items among theoretical compartments, taking into account the areas of their location along the length of the vessel;

d) summarize in tabular form all load items for theoretical compartments and determine the position along the length of their center of gravity;

e) using the total data, construct a stepwise mass curve.

The report must contain source data, short description mass distribution method, a breakdown of masses into theoretical compartments in tabular form, as well as a diagram of the ship’s compartments and a stepped mass curve in A-4 format.

10.4. Control questions

1) Name the main elements of the ship’s mass load and describe the nature of their distribution along the length.

3) Describe the method of dividing the masses of the body according to the trapezoidal rule.

4) Describe the rules for dividing mass load items along the length of the vessel.

PRACTICAL WORK No. 11

The bottom design without a double bottom is used on small transport vessels, as well as on auxiliary and fishing fleet vessels. The cross braces in this case are floras - steel sheets, the lower edge of which is welded to the bottom plating, and a steel strip is welded to the upper edge. The floras go from side to side, where they are connected to the frames by the zygomatic brackets.

The longitudinal connections of the bottom frame on ships without a double bottom are bar and vertical keels, as well as bottom stringers.

The bar keel is a steel beam of rectangular cross-section, which is connected by welding to the vertical keel, and to the bottom plating - either by welding or rivets. Another type of timber keel is three steel strips, one of which (the middle one) has a significantly larger width and is a vertical keel.

The vertical keel is made of a steel sheet placed on edge and running continuously along the entire length of the vessel. The lower edge of the vertical keel is connected to the timber keel, and a strip is welded along its upper edge.

Bottom stringers are also made from steel sheets, but unlike the vertical keel, these sheets are cut at each floor. The bottom edge of the sheets of bottom stringers is connected to the bottom plating, and a steel strip is welded along their top edge.

Bottom set on ships with a double bottom (Fig. 2). All dry cargo ships with a length of more than 61 m have a double bottom, which is formed between the bottom plating and the steel flooring of the second bottom, which is laid on top of the bottom frame. The height of the double bottom is at least 0.7 m, and on large ships 1 -1.2 m. This height allows work to be carried out on the double bottom during the construction of the vessel, as well as when cleaning and painting the double bottom compartments during operation.

The transverse connections of the bottom frame on ships with a double bottom are floras, which are of three types:

Solid;
Waterproof;
Open (lightweight brackets).

A solid floor consists of a steel sheet placed on an edge. The lower edge of the floors is connected to the bottom lining, and the upper edge is connected to the second bottom flooring. In the continuous flora there are large oval cutouts - manholes, which provide communication between the individual cells of the double bottom. In addition to large cutouts, several small cutouts are made in the sheet of solid flora near the bottom lining and at the flooring of the second bottom - dovetails for the passage of water and air.

Waterproof flor is structurally no different from solid flor, but it does not have any cutouts.

The bracket (open) floor does not have a solid sheet, but consists of two profile steel beams, the lower one, which runs along the bottom lining, and the upper one, which goes under the second bottom flooring. The upper and lower beams are connected to each other by rectangular pieces of sheet steel - brackets.

Rice. 1 Bottom set on ships without a double bottom: 1 - timber keel; 2 - vertical keel; 3 - horizontal strip of vertical keel; 4 - flor; 5 - upper flora stripe; 6 — bottom stringer sheet; 7 — bottom stringer strip; 8 - knitsa; 9 — frame

The longitudinal connections of the bottom frame on ships with a double bottom are the vertical keel, outer double-bottom plates and bottom stringers.
A vertical keel is a sheet placed on an edge and running in the center plane continuously along the entire length of the vessel. It is waterproof and divides the double bottom into sections on the left and right sides. Instead of a vertical keel, a tunnel keel can be installed, which consists of two sheets running parallel to the center plane at a distance of 1 - 1.5 m from each other.
On the sides, the double-bottom space is limited by double-bottom sheets (chine stringers), running continuously along the entire length of the double bottom and without any cutouts. The bottom edge of the double-bottom sheet is connected to the outer skin, and the top edge is connected to the second bottom flooring. The outermost double-bottom sheets are usually installed obliquely, as a result of which bilges are formed in the hold along the sides, in which bilge water collects.
Bottom stringers are vertical sheets installed on either side of the vertical keel. They are cut on each solid floor, and for the passage of the lower and upper beams of the bracket floor, cutouts of appropriate sizes are made in the stringer sheet.
Rice. 2 Bottom set on ships with a double bottom: 1 - second bottom flooring; 2 - waterproof floor; 3 — bracket (open) floor; 4 - solid flor; 5 - vertical keel; 6 — bottom stringer; 7 - outermost muzzle leaf (zygomatic stringer)
The cross braces of the side set are frames. There are ordinary and frame frames. Ordinary frames are made of profile steel (unequal flange angle, angle bulb, channel and strip bulb). The frame frame is a narrow steel sheet. This sheet welded seam is connected to the side plating, and a steel strip is welded along its free edge.
Frame frames have increased strength and therefore they are installed, alternating with ordinary ones, on ice-going vessels. But installing frame frames is not always advisable, as they clutter the room. Therefore, on ships that do not have ice reinforcements, frame frames are installed only in the engine room, and in the bow hold, where increased strength is required, ordinary frames with an increased profile are installed - reinforced or intermediate frames.
Rice. 3 Side set: 1 - frame frame; 2 - ordinary frames; 3 — side stringer; 4 - outer skin; 5 — diamond-shaped overlay
The lower end of the frame is attached to the outermost double-bottom sheet with a zygomatic bracket, which is welded with one edge to the outer skin, and the other to the double-bottom sheet. The flange is bent along the free edge of the zygomatic book.
The longitudinal connections of the side set are the side stringers. They consist of a steel sheet, along the free edge of which a steel strip is welded. The other edge of the side stringer sheet is attached to the side skin. To allow the passage of the frames, cutouts are made in the stringer sheet. On frame frames and transverse bulkheads, the side stringers are cut.
The cross braces of the under-deck set are beams, which run continuously from one side to the other, where they are connected to the frames by beam brackets. In those places where there are large cutouts in the deck (cargo hatches, machine-boiler shafts, etc.), the beams are cut and they go from the side to the cutout. Cut beams are called half beams. The half-beams at the side are connected to the frames, and at the cutout - to the longitudinal coaming of the hatch or shaft.
Beams and half-beams are made of profile steel (unequal angles, channels, angle bulbs, strip bulbs). At the ends of cargo hatches, as well as at the locations of deck mechanisms, frame beams are sometimes installed, which are a T-beam consisting of a steel sheet, along the free edge of which a steel strip is welded.
Rice. 4 Below deck set: 1 - deck flooring; 2 - beams; 3 - carlings; 4 - pillers; 5 - beam knives; 6 — frames; 7 — side trim
To reduce the span of the beams, longitudinal under-deck beams are installed - carlings, which create additional supports for the beams. The number of carlings depends on the width of the vessel and usually does not exceed three. Carlings have the same design as the side stringer. It also consists of a steel sheet, which is welded at one edge to the deck deck, and a steel strip is welded to its free edge. To allow the beams to pass through, cutouts are made in the frame sheet.
Intermediate supports for carlings are pillars - vertical tubular posts. The upper end of the pillar is connected to the carlings, and the lower end rests on the flooring of the lower deck or second bottom. To ensure that the pillers clutter up the hold less, they are installed only in the corners of the cargo hatch. On new ships, pillars are usually not installed, and the rigidity of the deck is ensured by the increased strength of the pillars.

Longitudinal dialing system
It is characterized by the presence of a large number of longitudinal beams running along the bottom, sides and under the deck. These beams are made of profile steel and are installed at a distance of 750-900 mm from each other. With such a number of beams, it is easy to ensure the overall longitudinal strength of the ship, since, on the one hand, the beams participate in the overall bending of the ship, and on the other hand, they increase the stability of thin sheets of plating and deck flooring.
Transverse strength with such a framing system is ensured by widely spaced frame frames and often placed transverse bulkheads.

Frames running along the sides, bottom (bottom frame frame or floor) and below the deck (frame beams) are installed every 3-4 m. The frame frame is made of steel sheet 500-1000 mm wide. One of its edges is welded to the outer skin, and a steel strip is welded along the other. For the passage of longitudinal beams
Cutouts are made in the frame sheet.

Rice. 5 Typesetting systems: a - longitudinal; b - combined, 1 - frame frame; 2 - booklets; 3 — transverse bulkhead; 4 — bulkhead pillars; 5 - outer skin; 6 — longitudinal beams; 7 — frames; 8 - zygomatic ridges; 9 — bottom frame frame (flor); 10—bottom flora; 11 — transverse bulkhead
Transverse bulkheads on ships with a longitudinal system must be installed more often than with a transverse system, since widely spaced frame frames do not provide sufficient transverse strength of the vessel. Typically, bulkheads are installed at a distance of 10 - 15 m from each other.
On transverse bulkheads, the longitudinal beams are cut and their ends are attached to the bulkheads with large brackets. Sometimes longitudinal beams are passed through bulkheads, and to ensure the tightness of the passage, they are scalded.
The longitudinal bracing system is used only in the middle part of the vessel's length, where the greatest forces arise during general bending. The ends on ships of the longitudinal system are made according to the transverse system, since additional lateral loads may apply here
The longitudinal dialing system has the following advantages:
Easier overall strength compared to the transverse system, which is very important for large vessels with a long length and relatively low side height;
Reducing the body weight by 5-7% with the same strength as the transverse system;
A simpler construction technology, since the longitudinal beams are mostly rectilinear in shape and do not require pre-processing.

However, this system has a number of disadvantages:
Cluttering the ship's premises with a frame set and a large number of brackets;
Limiting the length of holds by frequently installing transverse bulkheads, which complicates cargo operations.

For these reasons, the longitudinal system of recruitment is almost never used on dry cargo ships. But it is widely used on oil tankers, where these disadvantages are not significant. Oil tankers assembled using a longitudinal system have one or two longitudinal bulkheads in the area of cargo tanks, which are also constructed using a longitudinal system.

Combined dialing system
When the ship bends, the longitudinal connections of the deck and bottom will be most stressed. The longitudinal connections of the sides are less stressed. Therefore, it is irrational to install longitudinal beams along the sides, since they have an insignificant effect on the overall strength of the vessel. It is more expedient to have transverse beams along the sides and thus ensure lateral strength.
Based on this academician. Yu. A. Shimansky in 1908 proposed a combined framing system, in which the bottom and deck are made according to the longitudinal system, and the sides are made according to the transverse system. This combination allows the most rational use of the material and relatively easily ensures both longitudinal and transverse strength. The presence of longitudinal beams along the deck and bottom makes it possible to maintain the advantages of the longitudinal system, and the presence of transverse beams of the side eliminates its disadvantages, since in this case the frame set and frequent installation of transverse bulkheads are unnecessary.
Rice. 6 Midship frame of the vessel of the transverse system: 1 - floor; 2 - vertical keel; 3 — bottom stringer; 4 - pillers; 5 — double-bottom sheet (zygomatic stringer); 6 - zygomatic book; 7 — bilge frame; c — side stringer; 9 — beam book; 10 — beam of the lower deck; 11 — tweendeck frame; 12 — upper deck beam; 13 — bulwark stand; 14 — gunwale; 15 - about the longitudinal hatch coaming
The combined recruitment system is used on both dry cargo and oil tankers. In this case, dry cargo ships are made with a double bottom, assembled according to a longitudinal system. In this case, instead of longitudinal beams made of profile steel along the bottom and under the second bottom flooring, it is allowed to install additional bottom stringers with large cutouts.

Image of a ship's set on ship's drawings
One of the main ship drawings is the midship frame (Fig. 6) - the cross section of the ship. Due to the fact that the design of the set on the same ship may be different in different places, usually not one section is drawn, but several, which makes it possible to give a complete picture of the design of the ship's set.

Rice. 7 Constructive longitudinal section of the body along the center plane
Another design drawing of a ship set is a structural longitudinal section of the hull along the center plane. This drawing usually shows in the form of a diagram all changes in the design of the set along the length of the vessel (Fig. 7).
In addition to these basic drawings of the ship kit, many drawings of individual structural units, etc. are drawn.

The decks of seagoing vessels have predominantly a continuous steel deck made of sheets laid along the ship and forming, as always, a series of belts. Thus, the grooves, which are the connection of the belts with each other, all run parallel to the center plane of the vessel. However, here it is necessary to note one belt with its groove, which is an exception from the rest. This is a belt adjacent to the side of the ship, which, as can be seen from Fig. 89, runs parallel to the side of the ship, and not parallel to the centerline of the ship. This belt, which plays a large role in the flooring of the deck, and at the same time in the longitudinal strength of the ship, is called a deck stringer. It is mandatory for any deck - regardless of what the rest of its flooring is, steel or wood.

Sheets deck stringer have a thickness significantly greater than the thickness of other deck sheets. With the side of the ship, as we saw in the previous paragraph, the sheets of the deck stringer are connected by running along the deck along the side deck stringer angle. For the open upper deck, where this angle is always continuous, its dimensions are taken to be quite substantial, given its role in the longitudinal strength of the ship.

The thickness of the sheets of all the ship's chords, including the deck stringer, becomes thinner as it approaches from the middle of the ship to the ends, up to a certain minimum thickness. Where the deck begins to narrow at the ends, the sheets adjacent to the deck stringer are cut along the line of the stringer groove (see Fig. 89).

The connection of sheets to each other near decks is usually done in a covering with one-sided flanking. However, lap joints can also be recommended for open steel decks, as shown in Fig. 79. 2 At joints, the connection is sometimes also made on planks. The joints, in terms of the number of rows of rivets and their spacing, are made much stronger than the grooves. The joints of the deck stringer are especially strong. The joints of the sheets of the deck stringer of the upper deck should not at all be opposite the joints of the adjacent shearstrake; the spacing of these joints should be no less than spacing. The grooves and joints are mated to each other in the same way as was the case with the outer cladding and the second bottom flooring.

For access to the interior and individual compartments of the ship, cutouts called hatches are installed in the deck, many of which reach a significant size. The latter include primarily: cargo hatches, leading to. cargo holds of the ship, and engine light hatch, located on the deck directly above the main engine installed in the engine room of the ship, as well as boiler hatch- above the boiler room. Small hatches include similar hatches to residential and service spaces below deck. The cutouts on the deck also include the necks of the bunkers (less commonly, coal hatches - instead of necks) and openings for bringing ventilation pipes onto the deck. As you can easily imagine, when cutting a hatch or other hole in the deck, we, depending on the size of this cut, weaken the strength of the deck to a greater or lesser extent. Only those belts of the deck flooring that run continuously outside the line of large hatch cutouts in the deck participate in the longitudinal strength of the ship. It is clear, therefore, that from the point of view of the longitudinal strength of the vessel, only at these belts is it of interest to have a fairly solid thickness of sheets; As for the sections of the deck flooring located between the hatch cutouts, there is no need to take large thicknesses of sheets from them, as they do not participate in the longitudinal strength. It is only important that the thickness of these sheets be sufficient to withstand the local deck load that falls on them. Thus, the belts of the deck flooring inside the line of cutouts for cargo hatches are not counted at all towards the longitudinal strength of the vessel. The weakening of the sheets of the remaining belts with small cutouts must be compensated for. This compensation is usually done by doubling the weakened sheet.

Cracks often appear in the corners of large hatch openings due to a sharp change in the deck cross-section.

Rounding the corners and installing overlay sheets at the corners prevents the appearance of cracks, and therefore is always done on the upper, most stressed decks (Fig. 89).

The upper continuous deck must have such a flooring that the cross-sectional area of the continuously running chords (including the deck stringer and its corner) is sufficient to withstand the stresses arising in the deck flooring when the ship bends on a wave.

It is assumed that these stresses, and with them the indicated cross-section, depend on the length of the vessel, the height of the side to the upper continuous deck and the cargo draft of the vessel.

The flooring of the lower decks depends mainly on the load on them. The flooring of these decks has thicknesses that are less than the thickness of the sheets of the upper continuous deck.

In the case of a long middle superstructure, the deck will experience the greatest stress, and the upper deck under the superstructure will be less stressed. At the ends of the superstructure, the upper deck will experience additional local stresses in the same way as was indicated when describing the design of the shearstrak at the ends of the superstructure. In this regard, under the superstructure, the decking of the upper deck (including the deck stringer and its corner) may have dimensions corresponding to the lower deck, i.e., weakened, but on the deck of the superstructure itself, the decking and, especially, the stringer should be taken from the calculation of providing them with the proper longitudinal fortresses in this part of the ship. However, in this case, the upper deck flooring must, without reducing its thickness, extend inside the superstructure over an extent of at least 1/3 of the width of the vessel from the ends of the superstructure and, in addition, at the ends of the long middle superstructure, the upper deck stringer must be increased in thickness by 50 % versus its thickness along the upper deck outside | superstructure, and it must have this increased thickness by at least 3 spacing forward and aft from each end of the superstructure.

In the case of a ship with an elevated deck (quarterdeck), in the place where the deck ledges, a certain weakening of the strength of the ship naturally results, since the deck loses its continuity in this place. To compensate for this weakening, the following local reinforcements are made in this place: 1) the flooring of the upper deck (together with the stringer and its square) is extended into the quarterdeck for at least 4 spacing; 2) in turn, the stringer of the elevated deck extends beyond the ledge of the lube along the raised side at the place of the ledge for at least 3 spacing, gradually disappearing; 3) between two decks extended for at least 4 spacing above each other (as was just said in paragraph 1, inside the ledge, diaphragms in the form of brackets are placed from side to side at a distance of no more than 1.5 m from each other, consisting of rectangular sheets connected to the decks by short double angles. In small ships, these brackets are sometimes replaced by external brackets that reinforce the ledge.

The cutouts for hatches in the decks have a steel sheet fencing on all four sides with a height of 450 mm and higher, counting from the deck, forming the so-called hatch coaming. For cutouts in the deck located inside superstructures or deckhouses, as well as at necks and bunkers, the height of the hatch coaming is taken to be lower; the height of round coamings of ventilation outlets to the deck is taken from 750 to 900 mm. The thickness of the coaming sheets is taken depending on the size of the hatch and the size of the vessel.

The commings is connected to the deck by means of a lining square running around it. If the coaming has a significant length and height, then to give it rigidity, a reinforcing horizontal rib made of profile steel is placed along it at a certain height from the deck (see Fig. 90). With a greater height and length of the coaming, this rib is also supported by vertical posts (not shown in the figure. See Appendix).

Rice. 90. Reinforced commings.

Deck decking is not always made from steel sheets; Often, for decks of short superstructures and deckhouses, and sometimes for other decks, the use of steel sheets is abandoned, and the deck is covered with pine (or teak) boards, with a thickness of 50 to 85 mm. To replace the missing solid steel decking, it is recommended to install a series of steel sheets under the wooden decking. messengers belts laid over the beams. Typical connected belts are shown in Fig. 91 They provide the necessary ligation of the beams on which the wooden flooring is placed.

In addition, as stated above, if there is a wooden deck, a deck stringer is still required. The ends of the tie belts must, of course, overlap each other and onto the deck stringer and be riveted to them with a double seam.

Rice. 91. Location of tie belts under wooden flooring.

Wood flooring boards are laid along the vessel, attached to the beams with galvanized steel bolts. To obtain a smooth deck, the bolt heads must be recessed into the body of the board, and to maintain watertightness, they must be so deep that the cutout for the bolt head on top can be closed with a plug. The grooves and joints of the wooden flooring are caulked and filled with resin to make them waterproof.

The wooden flooring does not fit close to the side, but a so-called waterways, i.e. the gutter shown in Fig. 92.

Rice. 92. Waterways.

The waterway is either left open or cemented. To form a waterway, as can be seen, angles are used, running along the deck stringer, and the internal angle is called waterway. One more feature should be noted in the installation of wooden flooring, namely, the flooring is placed in such a way that it does not have the ends of the boards directly touching the metal surfaces. This is achieved by appropriately placing the boards in such places, as is particularly shown in the placement of the waterboard in Fig. 93.

Rice. 93. Butting the ends of deck boards.

As this is particularly shown in the arrangement of the waterway beam in Fig. 93.

Often wood decking is placed on top of solid steel decking. This must be done in relation to open decks under which there are living spaces. Lower decks in living areas should also be covered with wood. In addition, such flooring on open decks is made on passenger ships to make it easier to walk on deck, especially in wet weather and heat. If there is a wooden deck, the steel deck underneath can be somewhat lightened. The boards are bolted to the steel flooring in the same way as mentioned above.

Now let's move on to consider those connections on which the deck flooring we examined essentially rests on.

The deck flooring is placed on transverse deck braces - beams, running from side to side, with the exception of those places where there is a hatch cutout in the deck. In the last places the beam goes only from the side to the hatch comming and gets the name half beam. Beams are not always placed on every frame; It is used, especially on wooden decks and superstructure decks, to install beams through the frame, but of course with a corresponding increase in their strength. In any case, installation of beams on each frame is necessary on all steel waterproof decks and platforms and on the upper decks, which are a continuous strong connection of the ship’s hull. At the side, beams and half-beams are attached to the frames with brackets, as discussed above.

It should be noted that nowadays it is becoming less and less common to pass the end of the beam onto the frame, turning their flanges in different directions and passing the bracket between the frame and the beam. The work is much simpler with the connection method we currently use, when the beam is only butted to the frame with the flanges facing one way and with the bracket placed on the reverse side, as shown in Fig. 94.

Rice. 94. Connection of the frame with the beam.

The half-beams are attached to the hatch coamings with short connecting angles, which are taken double if the half-beams are installed through the frame; the number of rivets on each flange of this square should be at least two, and with significant dimensions of the half-beam profile - more.

In places where it is required to have local reinforcement of the deck, due to the presence of large loads in this place, reinforced or widened (frame) beams are used, which are similar in design to the same frames mentioned earlier (p. 56). Sometimes these beams are placed in combination with frame frames to form a rigid frame within the ship's hull. The use of widened frame beams at the ends of long hatches is especially common, which we will return to below.

Beams always carry steel or wood flooring; however, in previous designs, so-called idle beams were also used, which were placed without flooring in the holds of the ship, their purpose being to additionally tie the sides of the ship together. At present, the use of idle beams has been preserved only in peaks, where their installation is mandatory (as shown in Fig. 55) in each row of side stringers; these beams are placed through the frame.

Beams and half-beams carry the deck load and the greater the span from side to side or from side to coaming, the greater, of course, the strength the beam has to be given. To facilitate the work of the beam, already on wooden ships, as we have seen, pillars were used to support the beam in its span from side to side. Such beam supports are even more widely used in modern ships. By supporting the beam in its flight by means of pillars, the profile of the beam can be made much lighter. With a large vessel width, it is not necessary to limit oneself to one row of pillars placed in the center plane, but it is necessary to install two or three rows of pillars at equal, if possible, distances between each row. If, according to local conditions, the width of the vessel, i.e., the length of the beam, is divided by rows of pillars into an unequal number of parts, then of course in this case the profile of the beam will be determined by the size of the largest of the unequal spans. In addition to the distance between the rows of pillars, to determine the size of the beams, the distance between the beams and the nature of the load that the deck has to bear are also important.

Carlings running on top of the pillars under the beams make it possible to place pillars not under every beam. Taking a more solid pillar, you can use a carling to support several beams at once, located in the span from one to another adjacent pillar. Currently, this design of solid, widely spaced pillars, carrying a large strength carling, supporting up to a dozen beams at once, is finding very wide application. The advantages provided by such a design, which minimizes the clutter of the hold with pillers, are quite clear. Therefore, if light, frequently spaced pillers, the design of which is shown in Fig. 95, and are found on modern ships, sometimes relatively rarely, and then on small ships. Such a pillar consists of a round or tubular section, with its lower end, a shoe, resting on the flooring of the second bottom or the flooring of one of the decks (if this pillar is between decks), and the upper end of the pillar is attached to this beam or to a light carling made of a double square ( if the pillars are installed through the frame, and the beams are on each frame.

Rice. 95. Light pillers.

Of course, the design of widely spaced pillars carrying a solid carling is more complex. The number of such carlings in modern ships is usually taken to be two or three, and the carlings are carried, if possible, along the ship along the same line, sometimes getting somewhat closer to each other as they approach the collision and stern bulkheads, where the width of the ship becomes smaller.

Carlings (shown in section in Fig. 96) is a solid riveted beam made of a vertical sheet, which has cutouts in its upper part for passing beams through it, which are never cut on the Carlings. At the bottom, continuously running profile beams are riveted to the sheet (in the figure - corner bulbs); along the upper edge there are intercostal angles between the beams, connecting the carlings with the deck flooring (or with a longitudinal connected belt in the absence of a continuous steel flooring near the deck). In addition, in places where the beam passes through the carlings, the latter is connected to the carlings sheet with a short vertical square, as can be seen in Fig. 97. This short square, as shown in the same figure, extends downwards through one beam to the full height of the carling. From below, the carlings, at a distance of several meters from each other, are supported by pillars, which are taken either from large-diameter thick-walled pipes or are riveted from several profiles, usually channels. In the place where the pillars rest on the carlings, to give the latter greater rigidity, large brackets are placed, visible in Fig. 96: in this place a rigid knot is formed, into which the piller rests. The connection of the pillar with the carling is carried out with tubular pillars using a collar made of a square placed at the end of the pillar and a hexagonal horizontal sheet riveted on top of this collar.

Rice. 96. Carlings.

The sheet and horizontal rod of the collar are riveted with the flanges of the lower profiles of the carlings and with short horizontal double angles placed on each knit.

Rice. 97. Longitudinal view of the carlings.

The dimensions of the carlings and pillars depend on the magnitude of the load they carry, i.e., on the nature of the deck cargo (on the purpose of the deck), on the size of the span between the pillars and on the size of the distance between the rows of pillars. Moreover, if the ship has several decks and if each of the decks has its own row of carlings, then they try to place the pillars one above the other, so that the pillar directly bears the load from the pillars standing above it (pillars are made of a strength appropriate for this purpose). If this cannot be accomplished, then the load naturally increases on those carlings or beams on which the heel of the pillar above rests, which requires strengthening the profile of the corresponding carlings or beams (the beams in this case have to be made frame). In any case, they strive to ensure that this heel rests at the place where the carlings intersect with the beam. In a similar way, they strive to ensure that the heel of the bilge pillar, resting on the double bottom, falls at the intersection of the floor with the bottom stringer. If the latter is absent in this place, then instead of a stringer, short “suspended” half-stringer-brackets are installed between the floras by one space in each side of the flor, with a height of half the height of the double bottom and riveted to the inner bottom and floras.

A solid carling, carrying a whole series of beams with the entire deck load falling on them, at the same time is an essential longitudinal connection of the ship, especially, of course, near the upper continuous deck of the ship.

We considered the case of a carling going below the deck, regardless of the presence of cargo hatch cutouts in this deck. The latter should in this case naturally fall in the middle between two rows of carlings. The width of the hatches should be less than the distance between the rows of these carlings. But other cases may also occur. Firstly, there may be a case, although quite rarely, of the installation of one Carling in the center plane of the vessel. In this case, the carling will break off at the hatch along its path; here he will have to contact the beam limiting this hatch, and this extreme hatch end beam in this case must be framed and especially solid, since the ends will be attached to it simultaneously with the carlings longitudinal hatch commings, which in turn bear the load from all the half-beams attached to them.

In this case, lightening the hatch end beam can be achieved by placing pillars under it (usually either in the center plane or at the corners of the hatch, if the hatch is long).

Finally, the second case is more common, in which it is possible to maintain the continuity of the longitudinal connection in the ship’s hull that is carried out by the carlings. In this case, you only have to set certain dimensions (or rather, width) of all cargo (and often engine and boiler) hatches of the ship. This width is taken to be close to one third of the ship's width. Then, as is easy to see, the carlings can be launched along the ship in such a way that they will coincide with the line of the longitudinal commings of the hatches and therefore it will be possible to obtain the most advantageous design, namely: insert the carlings from the corner of one hatch to the corner of the next; In the area of the hatch, a separate carling is no longer installed. And in this case, the comming, running along the same line with the carlings, is correspondingly strengthened and, together with the carlings, which are its continuation, forms one continuous longitudinal connection of the vessel. It is necessary, of course, that the place at the corner of the hatch, where the carlings mate with the coaming, be so solidly tied that the fortress in this place can be considered preserved. This is usually achieved by placing large horizontal brackets under this place, tying the carlings and the hatch end beam into one whole. and hatch commings. Pillers are usually placed in the same place. To such a reinforced coaming, the half-beams are attached alternately either by angles running the full height of the under-deck part of the coaming, or by means of a special bracket shown in Fig. 90.

Finally, the exceptionally solid construction of the carling is shown in the cross section of the vessel (Appendix 1), where it, in combination with the hatch coaming, forms a riveted beam of tubular cross-section.

As for the platforms in the hull of the ship, they, being nothing more than decks placed on short sections of the length of the ship, retain all those features of the set that are characteristic of the decks themselves. They differ only in that while the decks almost always, including the lower ones, retain the characteristic sheerness and sheerness of the platform, only in rare cases (when they have a significant extent) do they receive this curvature, usually they are completely horizontal surface. A set of platforms, in cases where these platforms are the top of a water or fuel compartment in a ship's hull, receive a particularly reinforced set (flooring, beams, carlings, pillars), as well as reinforced riveting, designed to withstand the internal pressure of the liquid inside the compartment.

6. Impermeable and permeable bulkheads, baffles and propeller shaft tunnel.

The presence of transverse watertight bulkheads is mandatory, as we know, for any sea vessel. The design of such a bulkhead, like any bulkhead and enclosure, consists of three main parts: a casing made of steel sheets, reinforcing ribs (racks) made of profile steel and a connecting lining angle, which serves to connect the bulkhead to the sides, the second bottom flooring and to the deck. At the point where the bulkhead is attached to the side of the ship and to the deck, as we know, the installation of frames and beams is not required, since the bulkhead itself creates a transverse strength for the ship at the place where it is installed. If, as is usually the case, the bulkhead, reaching the upper deck, must intersect one or more lower decks on its way, then the bulkhead is cut at the intersection, but not these decks.

The bulkhead sheathing is made up of sheets placed at the waist. The thickness of the sheets depends on the pressure that they need to experience in the case when on one side of the bulkhead there is a pressure of water filling the corresponding compartment. It is assumed that water can fill the entire compartment and the entire bulkhead will be under pressure.

The lower this or that section of the bulkhead plating lies from the top, the greater the pressure on it from the water and, therefore, the greater its thickness should be.

Since the hull height of a marine vessel is visual, the difference in the thickness of individual sections of the bulkhead plating along its height will also be significant. This leads to the currently accepted main method of design and arrangement of the skin of a watertight bulkhead, namely: the belts of this skin, having different thicknesses, are almost always located horizontally. The lower belt has the greatest thickness, while the belts above it have an increasingly decreasing thickness as they are located higher: the upper, thinnest belt must, however, have a thickness of at least 6 mm.

Based on the above, the vertical arrangement of the bulkhead sheet flanges can make sense only if the bulkhead height is small, about 2-2 1/2 m, which is often the case with inter-deck bulkheads. The riveting along the grooves and joints is the same and is single-row (only if the bulkhead height is more than 10 1/2 m, the joints should be double-row).

The connection of the grooves is always done face to face with flanking. At the point of passage through the afterpeak bulkhead of the propeller shaft, i.e. in the area where the stern tube is attached, the bulkhead sheet is doubled. It is not allowed to make holes in the bulkhead sheets (for example, to transfer water from one compartment to another), since such a hole, even if it was equipped with a closing valve, may accidentally become open. The passage through the bulkhead must be made watertight using bulkheads or flanges.

If in order to communicate between individual compartments it is necessary to install a door in the bulkhead (doors are not allowed in the collision bulkhead), then this door must not only be watertight, but must also have a device that allows it to be closed from the upper deck, as well as would always give an indication whether the this moment door or closed.

To give rigidity to the bulkhead, its skin is reinforced with racks running vertically the entire height of the bulkhead. The racks are located from each other, as a rule, at a distance of 750 mm, and at the collision bulkhead - at a distance of 610 mm. The distance of 750 mm can be increased to 900 mm; however, in this case, both the dimensions of the rack and the thickness of the bulkhead sheets must be taken larger. The racks are made of angles, corner bulbs or channels, riveted with their narrow flange with a single-row seam to the sheathing sheets.

When riveting the strut to the bulkhead skin, it is naturally riveted on the smooth side of the bulkhead (on which there are no flanged protrusions at the skin).

A bulkhead post with water pressure on the bulkhead is a bendable beam consisting of a profile and a belt riveted to it, formed, as we know, by a strip of sheathing adjacent to the profile. The strength of this beam must be sufficient so that it can withstand the load on it without causing significant deflection. Any beam will resist bending better the more strongly its ends are sealed.

We have already become acquainted with one of the most reliable methods in this regard for sealing the ends of any beam in the hull of a ship: this method of sealing consists of placing a bracket at the end of the beam. The same method is used to seal the ends of bulkhead posts; at the end of the rack there is a bracket, one end attached to the rack, the other to the flooring of the second bottom (if this is the lower end of the bilge bulkhead rack) or to the deck (see Fig. 98); The dimensions of the bracket are taken equal to no less than 2 1/2 the height of the rack profile.

In some cases, a bracket protruding along the deck or flooring of the second bottom can be inconvenient; in such cases, they resort to less solid sealing of the ends of the rack, using short squares, as can be seen in Fig. 99; It is clear that due to the lower strength of the seal at the end of the post, the latter has to be taken with a more solid profile to obtain the required strength. The number of rivets on a short square must be at least two.

Rice. 98. Seal the ends of the bulkhead post with a bracket.

In some cases, namely in lightly loaded bulkheads, such as bulkheads in the upper inter-deck space, the ends of the racks of such bulkheads are connected with only one rivet to the lining angle and for them the fastenings indicated above are not required. When fastening the ends of the rack with short squares, as well as in the just mentioned absence of fastening the ends of the rack, it is necessary to increase the riveting along these ends over an area equal to 15% of the length of the rack, by means of which the rack is attached to the bulkhead, namely, the pitch of the rivets should be no more than 4d. It should be noted here that, generally speaking, riveting on bulkhead pillars has a pitch equal to 7d, but for the collision bulkhead, as well as for bulkheads delimiting the water and oil compartments inside the ship’s hull, the pitch is made more often and is equal to 6d.

Rice. 99. Seal the ends of the post with a short square.

The racks of these last bulkheads also have increased strength, which is achieved by bringing them closer to each other at a distance of up to 650 mm and the obligatory placement of the brackets at the end. we are resistant.

Generally speaking, the pillars and plating of the bulkheads delimiting the water and oil compartments inside the ship's hull, as well as the platforms on top of these compartments, must have a strength that is fully consistent with the liquid pressure from inside the compartment.

If, with a large length of the strut of a watertight bulkhead, as well as with a large pressure of liquid inside the water or oil compartment, they want to obtain a strut of moderate size, then they resort to installing additional horizontal reinforcing ribs along the bulkhead, running the entire width of the bulkhead. These ribs are a wide shelf (shelf), running horizontally along the bulkhead and consisting of a sheet riveted to the bulkhead using a square; Along its free edge, the sheet has a profile riveted along it. We will have to look at the design of these horizontal ribs in more detail later when considering special designs of tankers.

Turning now to the consideration of the bulkhead lining square, first of all, we note that at present dry cargo ships have this square installed only on one side of the bulkhead. In this case, with a bulkhead height of more than 10 1/2 m, as well as with oil-tight bulkheads, the square is taken in such a way that it is possible to place a double-row riveting (checkerboard) on it. Connecting the bulkhead with the second bottom flooring by the side outer skin and deck, the lining angle, running along them continuously, simultaneously ensures the impermeability of this lining. The riveting step of the lining square, generally speaking, is quite frequent (5d); it is done along the flange adjacent to the outer skin, somewhat less frequently (1/2d) than along the flange adjacent to the bulkhead. This is done for reasons so as not to greatly weaken the ship’s hull in one annular section with rivet holes.

It should be noted that if the finishing square is placed on the same side of the bulkhead where its uprights are located, this will make it difficult to seal the ends of the bulkhead uprights. When installing the facing square on the other side of the bulkhead (as in Fig. 99), the flange adjacent to the bulkhead will have to intersect the overlap of the bulkhead sheets, which in turn will also complicate the work, requiring either the landing of the square flange in these places or the use of wedge-shaped spacers. The same thing, however, occurs with the other flange of the facing square when passing through the flanking of the grooves at the inner bottom flooring, but here this can be partially avoided by the previously mentioned (p. 83) transverse placement of the second bottom flooring sheets under the bulkhead. The same must be taken into account in relation to the shelf of the lining square running along the deck. Still, it is preferable to place the facing square on the side of the bulkhead opposite from the racks, on the so-called clean side, from which all the embossing of grooves, joints and facing squares is carried out.

If ships have an inter-deck watertight transverse bulkhead that is not in the same plane as the bulkheads lying below or above, then the section of the deck between it and these bulkheads must be completely watertight. If a transverse watertight bulkhead has a ledge in height, then the platform forming this ledge must have a strength equal to the strength of the bulkhead in that place in its height that corresponds to the location of the ledge. The impermeability of bulkheads, as well as the impermeability of decks and platforms, is tested by watering their seams from the unchained side with a stream of water from a hose. The bulkheads separating the water and oil compartments, including the collision and afterpeak bulkheads, as well as the corresponding platforms of these compartments, are tested for their impermeability by filling the compartment with water under pressure, depending on the purpose and location of a particular compartment.

We still have to consider the design of the intersection of longitudinal braces (keels, side stringers and carlings) running along the length of the vessel with transverse watertight bulkheads.

Previously, when it was considered necessary to carry out any connection in the hull of a ship without cutting it, the same was done with the indicated longitudinal connections: they were carried out continuously and passed through the transverse bulkheads encountered along their way, giving an impenetrable lining at the point of passage, similar to that shown in Fig. 39. However, at present, cutting them is quite permissible, provided that the cut place is properly secured with knits. Therefore, carlings, side stringers, bottom stringers and keelsons are cut on transverse bulkheads, with their ends secured to these bulkheads by means of solid brackets (2-3 spacing in size), placed opposite each other on both sides of the bulkhead. Accordingly, if any longitudinal connection generally ends on the bulkhead and is fixed on it by means of a bracket and at the same time it is not required to be carried further, then for greater rigidity of the embedding, the same additional second bracket is placed on the opposite side of the bulkhead opposite the first. The brackets securing the longitudinal braces to the bulkheads are equipped with bent flanges. Recently, sometimes, to reduce the clutter of the hold with brackets near vertical longitudinal connections, such as keelsons and carlings, horizontal brackets are used instead of the usual vertical ones.

It is necessary to focus on one more watertight part of the ship's hull - this is the tunnel (or corridor) of the propeller shaft. It goes, as we know, from the rear engine transverse watertight bulkhead aft through the aft holds to the afterpeak. The height of the tunnel is taken to be human height, i.e. about 180-190 cm in light. The shape of its section is visible in Fig. 100.

Rice. 100. Propeller shaft tunnel.

In a single-screw and three-screw vessel with a shaft running in the center plane, the tunnel is shifted slightly to the side (usually to the left) to form a passage on one side of the shaft. The same applies to side shaft tunnels. The tunnel has two walls with a vault. The sheets forming these walls and the vault are placed in longitudinal belts. The sheets near the vault are somewhat thinner than the walls. However, in the clearance of the cargo hatch, these sheets, on the contrary, thicken if protective wooden lining is not installed on the tunnel in this place. The joining of sheets and riveting are carried out in the same way as for the watertight bulkheads of a ship. From the inside, the tunnel lining is reinforced with transverse posts curved to the shape of the tunnel, placed from each other at a distance of no more than 900 mm. The ends of the racks must reach the flooring of the second bottom and, if the profile height is high, the racks must be attached to it with short angles. Along the tunnel along the second bottom flooring there is a lining angle connecting the tunnel wall to this flooring.

A watertight door leads into the tunnel from the engine room side, meeting the previously stated requirements for doors installed in watertight bulkheads. At the opposite end of the tunnel at the afterpeak bulkhead, the tunnel ends at the so-called recession, i.e., a waterproof enclosure more spacious than the tunnel itself, allowing more convenient work at the end of the tunnel at the gland of the stern tube starting here.

The recess consists of a low (slightly higher than the tunnel) transverse watertight bulkhead, standing several spacing in front of the afterpeak bulkhead and a watertight platform running from the top of the first bulkhead also to the afterpeak bulkhead. This platform is sometimes also given a vaulted shape. From the recess, modern large ships have a special exit to the upper deck, going vertically upward through a shaft constructed for this purpose. We will now get acquainted with the design of the mines by examining the enclosures inside the ship.

We will not have to dwell particularly on the design of permeable bulkheads, since it is not much different from impenetrable bulkheads. The only difference is that they are made lighter and less riveting and holes are allowed in them. Permeable bulkheads are very often found running along a vessel for a greater or lesser extent. Beams pass in such bulkheads through cutouts in the upper chord of the bulkhead. It should be noted that such a longitudinal bulkhead can be used as a support for the deck lying above, i.e., it can replace a number of pillars and carlings. This is how it is often done, and the bulkhead posts are treated as pillars, and they are placed under the beams no further than two spacing from each other.

The strength of the racks is the same as what would be required for pillars installed through the frame. The upper belt of the bulkhead, which replaces the carvings, is often made somewhat thicker than the underlying belt. In this case, the beams located between the racks are connected to the upper chord of the bulkhead by means of short angles.

Any other permeable bulkheads on the ship are usually located in small areas at an angle to each other and are often called partition. Particular attention should be paid to the bulkheads separating the coal pits in the ship. These bulkheads are not required to be watertight, but the density of the riveting should ensure that they are dusttight. These bulkheads must have sufficient strength of their sheets and posts; the latter should be placed I at a distance of no more than 2 spacing from each other, but not more than at a distance of one and a half meters. The ends of the posts are secured with short squares.

Among the enclosures, special mention should be made of the so-called mines. Shafts are installed on ships that have several decks in cases where these decks have hatches located one above the other and when they want to separate the gap between these hatches from the space between decks in order to thus isolate the latter from the hatches. Such shafts are always located near engine and boiler hatches ( machine and boiler shafts- superstructures facing the deck), and also often on cargo and passenger ships near the cargo hatches ( cargo hatch shafts). It should be noted that if there is no superstructure above the boiler room or engine room, then their shafts rise upward above the upper deck to a certain height (depending on the size and type of the vessel) and only then end at the top with reliable light hinged covers.

Each shaft consists of walls (sheets of which have a thickness of 5-8 mm) and vertical posts placed at a distance of no more than 900 mm from each other. Sheets of shaft walls are often located vertically - from the coaming of one hatch to the coaming of the next hatch. The walls of the shafts are connected to each other at the corners by means of an internal connecting angle or directly passing into one another, with a slight rounding corresponding to the rounding of the corners of the hatch coamings.

In conclusion, without dwelling specifically on the design of the superstructures and deckhouses of the vessel, since they are sufficiently covered in relation to their side set (for superstructures) and the set of decks where the set of the side and decks of the ship was considered in general, we will dwell only on the design of the end watertight bulkheads ship superstructures.

The aft bulkheads of these superstructures, as well as all external bulkheads of the deckhouses, are constructed from 5-8 mm sheets and racks made of angles, without securing their ends. The forward bulkheads of the middle superstructure and poop, not protected from the impacts of oncoming waves hitting the deck, require significantly greater strength. This is achieved by greater thickness of the sheets, arrangement of the racks no further than 750 mm from each other and their large profile, as well as by securing the ends of the racks, if not with brackets, then at least with short squares. To connect these bulkheads with the side at the level of the bulwark, horizontal brackets are installed - both on the inside of the superstructure along the side plating, and on the outside - along the bulwark, with each bracket extending for 2-3 spacing.

For access to the internal compartments of the vessel, watertight doors are installed in the bulkheads of superstructures and deckhouses. It should be noted here that in order to protect against accidental flooding of water inside the superstructure or deckhouse, it is imperative to install commings threshold, the height of which for some types of vessels and in some cases is required to be up to 450 mm.

(1) On ships over 125 m in length, at least one deck along the entire length must be covered with continuous steel; on ships of shorter length, steel decking must be present over a certain length of the upper deck, in the middle part of the ship - in any case.

(3) Such a connection prevents water from lingering on the deck at the edges of the grooves; flanking, if used, should be done in the same direction.

(5) Shown in Fig. 91 diagonal stripes are required only on sailing ships. For power-driven vessels, only longitudinal tie strips along the cargo hatches are required. Editor.

(6) The system of idle bilge beams is always installed with solid side stringers running along these beams. This system has as its main purpose to create additional support for the bilge frames. Editor.

(7) In this case, the carling is more often called a longitudinal underdeck beam. Editor.

(8) For small ships it is sufficient to have support for the beams only in the center plane, that is, to have only one row of pillars. In this case, there is no cluttering of the hold with frequently installed pillers. Editor.

(10) With tubular pillers, heel support is achieved in the previously indicated way - by means of a collar at the end of the piller.

(11) Floor pillers should rest against the floor in any case.

(12) For the collision bulkhead, increasing the distance between the posts is not permitted.

(14) The latter is also required for the collision bulkhead.

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Ship set design

Bottom set on ships without a double bottom (Fig. 49). The bottom design without a double bottom is used on small transport vessels, as well as on auxiliary and fishing fleet vessels. The cross braces in this case are floras - steel sheets, the lower edge of which is welded to the bottom plating, and a steel strip is welded to the upper edge. The floras go from side to side, where they are connected to the frames by the zygomatic brackets.

The longitudinal connections of the bottom frame on ships without a double bottom are bar and vertical keels, as well as bottom stringers.

Bottom set on ships with a double bottom (Fig. 50). All dry cargo ships with a length of more than 61 m have a double bottom, which is formed between the bottom plating and the steel flooring of the second bottom, which is placed on top of the bottom frame. The height of the double bottom is at least 0.7 m, and on large ships 1 -1.2 m. This height allows for work to be carried out on the double bottom during the construction of the vessel, as well as when cleaning and painting the double bottom compartments during operation.

The cross braces of the bottom frame on ships with a double bottom are floras, which come in three types: solid, waterproof and open (lightweight braces).

A solid floor consists of a steel sheet placed on an edge. The lower edge of the floor is connected to the bottom lining, and the upper edge is connected to the second bottom flooring. In the solid flora there are large oval openings - manholes, which provide communication between the individual cells of the double bottom. In addition to large cutouts, several small cutouts are made in the sheet of solid flora near the bottom lining and at the flooring of the second bottom - dovetails for the passage of water and air.

Waterproof flor is structurally no different from solid flor, but it does not have any cutouts.

The bracket (open) fleet has a solid sheet, and consists of two beams of profile steel, the lower one, which runs along the bottom plating, and the upper one, which goes under the flooring of the second bottom. The upper and lower beams are connected to each other by rectangular pieces of sheet steel - brackets.

Rice. 49. Bottom set on ships without a double bottom: 1- timber keel; 2- vertical keel; 3- horizontal strip of vertical keel;

4- flor; 5- top stripe flora; 6- sheet of bottom stringer; 7- strip of bottom stringer; 8- knitsa; 9- frame

The longitudinal connections of the bottom frame on ships with a double bottom are the vertical keel, outer double-bottom plates and bottom stringers.

On the sides, the double-bottom space is limited by double-bottom sheets (chine stringers), running continuously along the entire length of the double bottom and without any cutouts. The bottom edge of the double-bottom sheet is connected to the outer skin, and the top edge is connected to the second bottom flooring. The outermost double-bottom sheets are usually installed obliquely, as a result of which bilges are formed in the hold along the sides, in which bilge water collects.

Bottom stringers are vertical sheets installed on either side of the vertical keel. They are cut on each solid floor, and for the passage of the lower and upper beams of the bracket floor, cutouts of appropriate sizes are made in the stringer sheet.

Rice. 50. Bottom set on ships with a double bottom: 1- second bottom flooring; 2- waterproof floor, 3- bracket (open) floor; 4- solid flor; 5-vertical keel; 6-bottom stringer; 7- outermost muzzle leaf (zygomatic stringer)

On-board set (Fig. 51). The cross braces of the side set are frames. There are ordinary and frame frames.

Ordinary frames are made of profile steel (unequal flange angle, angle bulb, channel and strip bulb). The frame frame is a narrow steel sheet. This sheet is welded to the side skin, and a steel strip is welded along its free edge.

Frame frames have increased strength and therefore they are installed, alternating with ordinary ones, on ice-going vessels. But installing frame frames is not always advisable, as they clutter the room.
Therefore, on ships that do not have ice reinforcements, frame frames are installed only in the engine room, and in the bow hold, where increased strength is required, ordinary frames with an increased profile are installed - reinforced or intermediate frames.
Below-deck set (Fig. 52). The cross braces of the under-deck set are beams, which run continuously from one side to the other, where they are connected to the frames by beam brackets. In those places where there are large cutouts in the deck (cargo hatches, machine-boiler shafts, etc.), the beams are cut and they go from the side to the cutout. Cut beams are called half beams. The half-beams at the side are connected to the frames, and at the cutout - to the longitudinal coaming of the hatch or shaft.

Rice. 51. Side set: 1-frame frame;

2-ordinary frames, 3-side stringer; 4- outer skin; 5-diamond overlay
Beams and half-beams are made of profile steel (unequal angles, channels, angle bulbs, strip bulbs). At the ends of cargo hatches, as well as at the locations of deck mechanisms, frame beams are sometimes installed, which are a T-beam consisting of a steel sheet, along the free edge of which a steel strip is welded.
To reduce the span of the beams, longitudinal under-deck beams are installed - carlings, which create additional supports for the beams. The number of carlings depends on the width of the vessel and usually does not exceed three.
Carlings have the same design as the side stringer. It also consists of a steel sheet, which is welded at one edge to the deck deck, and a steel strip is welded to its free edge.

To allow the beams to pass through, cutouts are made in the frame sheet.

Intermediate supports for carlings are pillars - vertical tubular posts. The upper end of the pillar is connected to the carlings, and the lower end rests on the flooring of the lower deck or second bottom. To ensure that the pillers clutter up the hold less, they are installed only in the corners of the cargo hatch. On new hulls, pillars are usually not installed; the rigidity of the deck is ensured by the increased strength of the planks.

The longitudinal framing system (Fig. 53, a) is characterized by the presence of a large number of longitudinal beams running along the bottom, sides and under the deck.
These beams are made of profile steel and are installed at a distance of 750-900 mm from each other. With such a number of beams, it is easy to ensure the overall longitudinal strength of the ship, since, on the one hand, the beams participate in the overall bending of the ship, and on the other hand, they increase the stability of thin sheets of plating and deck flooring.
Transverse strength with such a framing system is ensured by widely spaced frame frames and often placed transverse bulkheads.
Frames running along the sides, bottom (bottom frame frame or floor) and below the deck (frame beams) are installed every 3-4 m. The frame frame is made of steel sheet 500-1000 mm wide. One of its edges is welded to the outer skin, and a steel strip is welded along the other. For the passage of longitudinal beams

cutouts are made in the frame sheet

Transverse bulkheads on ships with a longitudinal system must be installed more often than with a transverse system, since widely spaced frames do not provide sufficient transverse strength of the vessel. Typically, bulkheads are installed at a distance of 10-15 m from each other.

On transverse bulkheads, the longitudinal beams are cut and their ends are attached to the bulkheads with large brackets. Sometimes the longitudinal beams are passed through the bulkheads, and to ensure the tightness of the passage, they are scalded.

The longitudinal bracing system is used only in the middle part of the vessel's length, where the greatest forces arise during general bending. The ends on ships of the longitudinal system are made according to the transverse system, since additional lateral loads may apply here
The longitudinal framing system has the following advantages: it is easier to ensure overall strength compared to the transverse system, which is very important for large ships with a large length and a relatively low side height;
reduction in body weight by 5-7% with the same strength as the transverse system;

However, this system has a number of disadvantages:
a simpler construction technology, since the beams of the longitudinal set are mainly rectilinear in shape and do not require pre-processing.
cluttering the ship's premises with a frame set and a large number of brackets;

For these reasons, the longitudinal system of recruitment is almost never used on dry cargo ships. But it is widely used on oil tankers, where these shortcomings are not significant. Oil tankers assembled using a longitudinal system have one or two longitudinal bulkheads in the area of cargo tanks, which are also constructed using a longitudinal system.

Combined dialing system (Fig. 53, b). When the ship bends, the longitudinal connections of the deck and bottom will be most stressed. The longitudinal connections of the sides are less stressed. Therefore, it is irrational to install longitudinal beams along the sides, since they have an insignificant effect on the overall strength of the vessel. It is more expedient to have transverse beams along the sides and thus ensure lateral strength.

Based on this academician. Yu. A. Shimansky in 1908 proposed a combined system of framing, in which the bottom and deck are made according to the longitudinal system, and the sides - according to the transverse system. This combination allows the most rational use of the material and relatively easily ensures both longitudinal and transverse strength. The presence of longitudinal beams along the deck and bottom makes it possible to maintain the advantages of the longitudinal system, and the presence of transverse beams of the side eliminates its disadvantages, since in this case the frame set and frequent installation of transverse bulkheads are unnecessary.

Fig. 54 Midship frame of a transverse system vessel 1- floor, 2- vertical keel, 3- bottom stringer, 4- pillars, 5- double-bottom sheet (bilge stringer), b-chine frame, 7- bilge frame, c-side stringer, 9 - beam bracket, 10 - lower deck beams, 11 - tween deck frame, 12 - upper deck beams, 13 - bulwark post, 14 - gunwale, 15 - side hatch coaming

The combined recruitment system is used on both dry cargo and oil tankers. In this case, dry cargo ships are made with a double bottom, assembled according to a longitudinal system. In this case, instead of longitudinal beams made of profile steel along the bottom and under the second bottom flooring, it is allowed to install additional bottom stringers with large cutouts.

Image of a ship's set on ship's drawings. One of the main ship drawings is the midship frame (Fig. 54) - the cross section of the ship. Due to the fact that the design of the set on the same ship may be different in different places, usually not one section is drawn, but several, which makes it possible to give a complete picture of the design of the ship's set.

Rice. 55. Constructive longitudinal section of the body along the center plane

Another design drawing of a ship set is a structural longitudinal section of the hull along the center plane. This drawing usually shows in the form of a diagram all changes in the design of the set along the length of the vessel (Fig. 55).

In addition to these basic drawings of the ship kit, many drawings of individual structural units, etc. are drawn.

Material from Wikipedia - the free encyclopedia
Stability is the ability of a floating craft to withstand external forces that cause it to roll or trim and return to a state of equilibrium after the end of the disturbance. Also - a branch of ship theory that studies stability.
Equilibrium is considered to be a position with acceptable values of roll and trim angles (in a particular case, close to zero). A craft deviated from it tends to return to equilibrium. That is, stability manifests itself only when there is a disequilibrium.
Stability is one of the most important seaworthiness qualities of a floating craft. In relation to ships, the clarifying characteristic of the stability of the vessel is used. The stability margin is the degree of protection of a floating craft from capsizing. External impact can be caused by a wave blow, a gust of wind, a change in course, etc.
Stability is the ability of a ship, removed from a position of normal equilibrium by any external forces, to return to its original position after the cessation of the action of these forces. External forces that can displace a ship from a position of normal equilibrium include wind, waves, the movement of cargo and people, as well as centrifugal forces and moments that arise when the ship turns. The navigator is obliged to know the characteristics of his vessel and correctly assess the factors affecting its stability. A distinction is made between transverse and longitudinal stability.
Stability is the ability of a ship, deviated from an equilibrium position, to return to it after the cessation of the forces that caused the deviation.
The tilting of the vessel can occur due to the action of oncoming waves, due to asymmetrical flooding of compartments during a hole, from the movement of cargo, wind pressure, due to the receipt or consumption of cargo.
The inclination of the vessel in the transverse plane is called roll, and in the longitudinal plane - trim. The angles formed in this case are denoted by θ and ψ, respectively.
The stability that a ship has during longitudinal inclinations is called longitudinal. It is usually quite large, and there is never any danger of the vessel capsizing through the bow or stern.
The stability of a ship during transverse inclinations is called transverse. It is the most important characteristic of a vessel, determining its seaworthiness.
A distinction is made between initial lateral stability at small roll angles (up to 10-15°) and stability at large inclinations, since the righting moment at small and large roll angles is determined in different ways.