home Trips a brief dictionary of ship terms in pictures. Basic shipbuilding and maritime terms What is a piller on a ship

a brief dictionary of ship terms in pictures. Basic shipbuilding and maritime terms What is a piller on a ship

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 of uniform distribution of 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), using the accepted value of the critical voltage, determine the corresponding Euler voltage.

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 take into account deviations from Hooke's law, you should use diagram or figure 7.1 of these guidelines. 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 complex 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 "Design of ships 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 initial data, a brief description of the method of mass distribution, 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 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.
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 (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 transverse 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 beams of the longitudinal set are mainly 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 under-deck set consists of longitudinal and transverse beams, rigidly connected to a set of sides. The longitudinal beams are called below-deck stringers, and the transverse beams are called beams.

The beams are connected to the upper branches of the frames. Vertical posts are installed under the beams - pillers. The pillars support the decks and distribute the weight evenly across other connections.

The beams are cut in places where the decks are cut out. The ends of the beams are reinforced with short longitudinal beams - Carlings, which at their ends are connected to whole beams.

In deck sets above engine and boiler rooms in large areas, beams are not installed. To maintain strength, the outer beams of such sections are made reinforced, i.e. are made up of several beams and connected to frame frames.

= Sailor II class (p. 41) =

With a transverse deck building system, the beams of the main direction are beams and half-beams, and the longitudinal cross braces are carlings. Beams are installed from side to side on each frame and secured to the side frame using brackets. Intermediate supports for the beams are carlings and diametrical semi-bulkheads in the holds. Half beams are also located on each frame in the areas of large cutouts in the decks and rest on the sides and carlings installed along the cutouts. According to the Rules, beams can be continuous, i.e. pass without interruption through cutouts in the carlings, or split on the carlings. In the 1st case, the beams are welded to the edges of the cutouts in the carlings, which are reinforced with vertical stiffeners; in the 2nd case, at the junction of the beams with the carlings, brackets are installed on both sides of its wall. Half beams are also attached to the carlings using knits.

Carlings are welded to the transverse bulkheads and secured with brackets to reinforced racks, usually installed on bulkheads.

If the cargo hold is long, the carlings in the span are supported by pillars - vertical posts of tubular cross-section, which are installed in the corners of large cutouts. However, the pillars create interference when stowing cargo in the holds, so the pillars rest on frame beams located at the ends of the hatches and rest, in turn, on the diametrical semi-bulks located from the transverse bulkheads to the cutouts in the deck.

With a longitudinal system of deck slabs, the main direction beams are longitudinal under-deck stiffeners, the distance between which is taken to be equal to the distance between the bottom ribs. This arrangement of the longitudinal ribs of the decks and bottom with the vertical posts of the transverse bulkheads provides each rib with support on the bulkhead post. Intermediate supports for the under-deck stiffening ribs are frame beams, and in areas of large cutouts - frame half-beams. Longitudinal under-deck beams passing through the cutouts in the frame beams are welded to the edges of the cutouts, and vertical stiffeners are installed in the places where the beams pass along the walls of the frame beams. If below-deck beams are cut at transverse bulkheads, then the ends of the beams are connected to the bulkheads with brackets. The rules recommend installing one continuous bracket on each beam and welding it into the corresponding slot in the bulkhead sheet.

Sheets of deck coverings are placed along the vessel, which makes it possible to rationally distribute them across the width of the vessel, taking into account their thickness. The thickest sheets of deck flooring are those located at the sides of the ship - deck stringers, which are usually welded end-to-end to the shearstrake, or attached with rivets using a stringer angle. In this case, the riveted connection serves as a barrier against the propagation of cracks.

A feature of the deck flooring in the area of cargo holds is large cutouts for cargo hatches, which adversely affect the strength of the decks, causing stress concentration in their corners. To reduce stress concentration, the corners of the cutouts are rounded and reinforced with welded sheets with a thickness equal to 1.35 times the thickness of the reinforced sheet, but not more than 30 mm. Along the edges of large cutouts in the upper deck, a coaming with a height of about 600 mm, rounded at the corners, is installed, which prevents sea water from entering the holds, and also serves as reinforcement of the cutout, reducing stress concentration. Cutouts in the decks above the engine and boiler rooms are protected by longitudinal and transverse partitions for the entire height of the space between decks.

=Theory and structure of the vessel (p. 77)=

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.

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. 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.

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.
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.

Rice. 52. Below deck set: 1- deck flooring; 2- beams; 3- carlings 4- pillers; 5-beam booklets; 6- frames 7- side plating

Fig. 53 Framing systems: a - longitudinal, b - combined, 1 - frame frame, 2 - brackets, 3 - transverse bulkhead, 4 - bulkhead posts, 5 - outer skin, 6 - longitudinal beams, 7 - frames, 8 - zygomatic brackets , 9-bottom frame (flor), 10-bottom floor, 11-transverse bulkhead

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 transverse 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;
a simpler construction technology, since the beams of the longitudinal set are mainly 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 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.

Longitudinal elements (beams) vessel are:

keel- longitudinal beam of the bottom frame, running along the middle of the width of the vessel;
stringers- longitudinal beams of the bottom and side frame. Depending on their location, they are: side, bottom and zygomatic.
Carlings- longitudinal under-deck beams;

Longitudinal stiffeners - longitudinal beams of a smaller profile than those of stringers and carlings. Based on their location, they are called below-deck, side or bottom and provide rigidity to the outer skin and deck flooring during longitudinal bending.

Transverse elements of the vessel

Transverse elements (beams) of the vessel:

Floras are transverse beams of the bottom set, stretching from side to side. They are waterproof, solid and bracketed;
Frames are vertical beams of the side frame, which are connected below to the floors using brackets. A bracket is a piece of triangular-shaped sheet steel used to connect various parts of the body. On small vessels (boats), flora may be absent and the frames are solid beams of the side and bottom frames.
Beams are transverse beams of a deck set, running from side to side. If there are cutouts in the deck, the beams are cut and called half beams. They are connected at one end to the frame, and at the other they are attached to a massive coaming, which borders the cutout in the deck, in order to compensate for the weakening of the deck floor with cutouts.

On rice. 1 shows the simplest structure of the hull of a small boat, indicating the main elements of the set, and on rice. 2 a more complete set of wooden motor boat hulls is presented.

Rice. 1. Structure of the hull of a small vessel.
1 - stem; 2 - keel; 3 - stringer; 4 - side trim; 5 - transom; 6 - frame; 7 - beam; 8 - deck

The ship's frames are numbered from bow to stern. The distance between the frames is called spacing. Vertical, free-standing racks of round or other cross-section are called pillars.

Rice. 2. Elements of a wooden motor boat hull kit.
1 - casing; 2 - deck; 3 - beam; 4 - frame; 5 - seats; 6 - transom; 7 - motor mounting location;
8 - side stringer; 9 - fender; 10 - zygomatic stringer; 11 - keel; 12 - bottom stringers

The pillars serve to reinforce the deck and in its lower part rests on the intersection of the floors (frames - on small ships) with the bottom longitudinal beams (keel, stringer, keelson), and in the upper part - beams with carlings. Piller installation is shown in rice. 3.

Rice. 3. Piller installation
1 - deck flooring; 2 - carlings; 3 - beam; 4 - transverse coaming; 5 - pillers;
6 - second bottom flooring; 7 - flor; 8 - keel; 9 - bottom trim.

Vertical or inclined beams that are a continuation of the keel are called stems (in the bow - stem, in the stern - stern). The ship's hull can be divided into separate compartments using transverse and longitudinal watertight bulkheads. The bow of the ship between the stem and the first bulkhead is called the forepeak, and the aft compartment is the afterpeak. On powerboats, a watertight structure at the transom that forms a niche and is designed to accommodate the outboard motor is called the engine niche. The motor niche, located above the water level and equipped with scuppers - holes for draining water, is called a recess niche.
For a more complete picture of the elements of the body kit, see rice. 4 shows a cross-section of a dry cargo ship with a combined recruitment system, and Fig. 5th set of metal boat hull "Chibis".

Rice. 4. Combined dialing system.
1 - gunwale; 2 - bulwark stand; 3 - bulwark; 4, 10-beams; 5 - deck flooring; 6 - carlings; 7 - stiffener; 8 - hatch coaming;
9 - pillers; 11 - bulkhead pillar; 12 - transverse bulkhead; 13 - second bottom flooring; 14 - keel; 15 - horizontal keel; 16 - bottom stringer;
17 - bottom trim; 18 - flor; 19 - outer double-bottom sheet; 20 - zygomatic keel; 21 - zygomatic belt; 22, 25 - frame;
23 - half beam; 24 - side trim; 26 - knitsa; 27 - shearstrek.

Rice. 5. Boat hull set.
1 - frame frame; 2 - carlings; 3 - coaming; 4 - deck flooring; 5 - fender; 6 - frame; 7 - side trim;
8 - zygomatic square; 9 - flor; 10 - stringer; 11 - keel; 12 - bracket; 13 - bottom plating; 14 - knitsa.

External cladding

The outer plating of the vessel ensures the waterproofness of the hull and at the same time participates in ensuring the longitudinal and local strength of the vessel. On metal ships, the hull consists of steel sheets placed with the long side along the ship. In addition to steel sheets, especially on metal motor boats and boats, sheets of aluminum alloys are used. Sheathing sheets are connected using rivets and butt welding. A series of planking sheets running along the ship is called a belt. The upper belt of the side skin is called shirstrvkom, and below there are side belts and on the cheekbone - the zygomatic belt. The middle bottom belt is called the horizontal keel. The line of connection of one belt with another is called a groove, and the place where the sheets join each other in one belt is called a joint. The sizes of sheets and their thickness are different and depend on the design of the vessel, its size and purpose. For the cladding of boats, motor, sailing and rowing boats, wood materials, laminated plastics, fiberglass, textolites and other materials that meet the requirements of shipbuilding in their properties and strength are very often used.

Deck flooring

The deck flooring ensures the watertightness of the hull from above and is involved in ensuring the longitudinal and local strength of the vessel. The greatest load during longitudinal bending falls on the deck in the middle part of the ship, so the deck sheets at the end are somewhat thinner than in the midship area. The flooring sheets are located with the long side along the ship, parallel to the centerline plane, and the outermost chords of the left and right sides are located along the sides; they are called deck stringers and are thick. The deck stringer is connected to the shearstrak by riveting, welding or gluing, depending on the material of the decking sheets.

Hatches and necks

Hatches and necks weaken the strength of the deck; stress concentrations arise in their corners, contributing to the appearance of cracks. In this regard, the corners of all cutouts in the hull plating are rounded, and the deck sheets at the corners of the cutouts are made more durable. To strengthen the deck, weakened by the cutouts, and to prevent water from entering the hatch, a coaming is made along the edges of the cutout, which has a device for closing the hatch (neck). The coaming also borders the cutouts in the bulkheads; the coaming is also called the part of the bulkhead under the doorway.

Bulwark and railing

On sea, river and modern pleasure boats, to protect people from falling overboard, open decks have a bulwark or railing.

Bulwark(rice. 6) is, as a rule, a metal belt of the side plating. It is installed on low decks prone to flooding in stormy weather.

Rice. 6. Bulwark.
1 - buttress; 2 - bulwark; 3 - gunwale; 4 - stiffening strut.

On the inside, the bulwark is supported by racks, which are called buttresses and are installed through two or three spacing. To increase the strength of the bulwark, ribs are sometimes welded between its posts. Along the upper edge of the bulwark, a strip is strengthened, which is called a gunwale. To drain water overboard that falls on the deck, cutouts are made in the bulwarks - storm porticoes. Considering that the complete removal of water through the storm ports is prevented by the deck stringer angle, then for complete drainage of water from the deck overboard, scuppers are made - cutouts in the edge of the shearstrake protruding above the deck and in the deck stringer angle. Railing fencing ( rice. 7) consists of vertical posts connected to each other by tightly stretched cables (rails) or chains.

Rice. 7. Guardrail (removable).

The racks can be connected to each other by two, three or four rows of horizontal round rods, most often steel. These horizontal rods are called rails.

Shipbuilding materials

There are basic materials used for the manufacture of hulls, kit elements, ship devices and parts.

Steel- has many properties necessary for building a ship (density 7.8 g/cm3). It is durable and easy to process. The most commonly used shipbuilding steels are carbon and low-alloy steels.

Sheet steel has a thickness from 0.5 to 4 mm (thin sheet) and 4 - 1400 mm. In shipbuilding, the most common sheets are 6-8 m long and 1.5-2 m wide. The following profiles are produced from carbon steels: angle, channel, I-beam, strip-bulb and z-beam, and from low-alloy steels the same profiles are produced, except z-beam and I-beam. Sheet steel is used to make hull plating, bulkheads, second bottom, decks, etc.; from the profile: beams, frames, stringers and other elements of the hull. The casting method produces parts of complex shapes: anchor fairleads, anchors, chains, stems, propeller brackets, etc.

Aluminum alloys have a lower density than steel (2.7 g/cm3) and sufficient strength. The most common are alloys of aluminum with magnesium and manganese. Small vessels, superstructures, partitions, pipelines, ventilation pipes, masts, ladders and other important ship parts are made from these alloys.

Wood and wood materials for many years (until the 19th century) they were the only material for building ships. Having many advantages, wood continues to be used in shipbuilding today. The hulls of small sea and river vessels, boats, dinghies, rowing boats, sports and sailing ships, deck coverings, decoration for ship premises, etc. are made from wood. Pine is most often used in shipbuilding. It is used to make kits and plating. Spruce is used for lining the underwater part of the vessel, because it is less hygroscopic. Larch and teak are used for decking and external cladding, for finishing residential and office premises - oak, beech, ash, walnut, birch and others. In addition, the stems of wooden ships are made from beech and ash, incl. undersized. Beams, boards, slats, plywood and wood slabs are widely used in shipbuilding, used for the manufacture of external cladding of ships, finishing of cabins, salons, etc.

Plastics Due to low density, good dielectric and thermal insulation properties, high corrosion resistance, convenient processing methods and sufficient strength, they increase the service life of individual ship parts. erasers are divided into two main groups: thermoplastics (plexiglass, nylon, polyethylene and other plastics that can again acquire a plastic state when heated and harden when cooled) and thermosets - plastics that cannot be re-softened when heated, i.e. plasticity. The most widely used in shipbuilding are fiberglass plastics - various synthetic resins (epoxy, polyester, etc.) reinforced with fiberglass in the form of fabric, mats, strands. Fiberglass is used to make small vessels (boats, boats, yachts, boats), pipes and other ship structures and parts.

The main disadvantages of plastics are: low heat resistance, low thermal conductivity, tendency to plastic deformation under the influence of constant load at normal temperature (creep).

Cast iron used for the manufacture of cast products: bollards, bale strips, stern tubes, propellers and other parts.

Bronze- an alloy of copper with tin or aluminum, manganese, iron. Sliding bearings, propeller shaft linings, kingston housings, worm wheels and other parts are made from it.

Brass- an alloy of copper and zinc. Pipes for heat exchangers, porthole parts, electrical parts, propellers and other products are made from it.

Reinforced concrete- a material consisting of concrete reinforced with a metal frame. It is mainly used for the construction of floating docks, cranes, and landing stages.

Superstructures and deckhouses

Superstructures are all enclosed spaces located above the upper deck from side to side. The bow superstructure is called the forecastle, the stern superstructure is called the poop. The middle superstructure has no special name. A superstructure having a width less than the width of the vessel is called a deckhouse. For example, the chart room. The design of decks and sides of superstructures and deckhouses is similar to the design of other decks and sides on ships. The side plating and bulkheads of superstructures, as a rule, are thinner and may differ in material from the hull.

﻿ a brief dictionary of ship terms in pictures. Basic shipbuilding and maritime terms What is a piller on a ship

Longitudinal dialing system

Combined dialing system

Image of a ship's set on ship's drawings