RU2667025C1 - Ship hull - Google Patents

Abstract

FIELD: shipbuilding.SUBSTANCE: invention relates to the field of shipbuilding, in particular to the design of ship hulls. Hull of the ship is proposed from separate parts formed from the outer skin and the beams of the set in the form of separate impermeable shells connected by an integral joint. Strength of the joint is chosen such that it ensures the joining of parts until the critical value of the hydrodynamic force P, which corresponds to the maximum permissible fall of the metacentric height for a given ship. Hull is made up of a main part made with a backward inclination of the stem and a blockage in the nose, and two parts, made in the form of boules, forming a flat surface of the deck in the bow of the hull of the ship and ensuring the collapse of the flange. Relation for determining the load P, at which separation of boules can occur.EFFECT: technical result is to improve the safety of navigation by eliminating the possibility of loss of stability and overturning.1 cl, 4 dwg

Description

The invention relates to the field of shipbuilding, in particular to the design of hulls.

A known design of the front of the displacement type vessel (RU 2374120, IPC B63B 1/06, publ. 11/27/2009) with transverse symmetry relative to the central axis, and the hull forming lines increase in width from the baseline. The bottom is flat or has a pitch and goes into the bottom with a given radius of the bottom. From the bottom to a predetermined height, the generatrix lines are slightly inclined outward. At the level of the deck of the tank, the shape of the outward sloping line stops and passes upward in the form of a curved line back in the direction of the central axis.

This design has the following disadvantages:

- the ship has a large windage;

- the wheelhouse is removed from the engine room, which makes it difficult to lay cable routes;

- poor habitability;

- shock waves can knock out windows in the wheelhouse and lead to damage to navigation equipment;

- at a high wave height, they can overlap through the superstructure, while the flat deck surfaces will contribute to the capture of the bow of the vessel by the wave [Burakovsky EP, Burakovsky PE Some problems of ensuring the general strength of ships in emergency situations // Transactions of the Krylov State Scientific Center. - Vol. 82 (366), 2014. - S. 21-30];

- poor germination per wave, because due to the slenderness of the waterline, the ship crashes into a wave, and it twists above the bow and to the side, as a result of which the bow of the ship can be captured by the wave, which will lead to the death of the ship.

The hull of the vessel is known, which is an impenetrable shell consisting of thin sheets that are supported by beams made of rolled or composite welded profiles (Barabanov N.V. Design of the hull of marine vessels. L .: Sudostroenie, 1981. - 552 p., P. 9-11, Figure 1).

This design has a significant drawback consisting in the possibility of capturing the bow of the nose by the wave, due to the presence of flat deck surfaces and the superstructure of the tank, as a result of which a metacentric height may fall and the vessel will tip over [Burakovsky E.P., Burakovsky P.E. Some problems of ensuring the general strength of ships in emergency situations // Transactions of the Krylov State Scientific Center. - Vol. 82 (366), 2014. - S. 21-30]. Capture of the nasal tip by a wave means that when the deck is flooded heavily, it operates in a submerged position as a wing streamlined by a liquid stream, as a result of which pressure forces arise on flat surfaces, which is determined by the angle of attack and the speed of the incoming liquid. This flow is unstable, as a result of which the resultant can at any moment move away from the diametrical plane and cause a strong roll or tipping of the vessel. Under the action of the resultant hydrodynamic forces, the trim of the vessel increases, while there is a sharp decrease in the transverse metacentric height, which contributes to the capsizing of the vessel.

Known hull with obstruction and reverse inclination of the stem (US 6601529, B63B 3/00, publ. 05.08.2003).

The disadvantage of this design is the low stability of the vessel, which can lead to capsizing and the death of the crew. This is due to the reduced waterline area compared to the traditional design, especially when passing wave crests, as well as to the low values of the restoring moment acting on the vessel during its heeling, which is due to the small volume of the vessel immersed in water during inclination.

The hull of the vessel (RU 2617866, IPC B63B 43/02, B63B 3/04, published April 28, 2017), made in the form of an impermeable shell formed from the outer skin and set beams, was adopted as the closest analogue, and the impermeable shell is made in in the form of two separate impermeable parts - fore and aft, connected by a one-piece connection located on the nose side of the hull from the mid-frame, the strength of which is chosen such that the parts are connected until the bending moment acting on the one-piece connection reaches the ultimate value associated with the critical value of the hydrodynamic force, which corresponds to the maximum allowable drop in the metacentric height for a given vessel.

This design has a significant drawback consisting in the poor seaworthiness of the feed impermeable part of the vessel, which should be afloat after separation of the bow impermeable part of the vessel to ensure crew rescue or movement to the port of refuge. The contours of the aft impenetrable part have unsatisfactory hydrodynamic characteristics, as a result of which, in stormy conditions, under the influence of waves, experiencing hydrodynamic shock of high strength, it can tip over, which will lead to the death of the crew.

The invention solves the problem of improving the safety of navigation, excluding the loss of the vessel in situations of capture by the wave of the bow tip, due to the implementation of the bow tip with the ability to change shape at a critical moment to improve hydrodynamic characteristics and seaworthiness.

To obtain the desired technical result in the ship’s hull, consisting of individual parts formed from the outer skin and set beams in the form of separate impermeable shells connected by an integral connection, the strength of which is chosen such that the parts are connected until the critical value of the hydrodynamic force P _cr , which corresponds to the maximum permissible drop in the metacentric height for a given vessel, it is proposed that the hull be made up of the main part, which must be performed with reverse inclination on the bow and the blockage of the side in the bow, and two parts made in the form of boules, forming a flat deck surface in the bow of the ship's hull and ensuring the collapse of the side. P _Dep load at which separation occurs boules, serves to determine from the following relation:

,

,

Where

P _cr - the critical value of the hydrodynamic force at which the ship loses stability, N;

S is the submerged deck area when the hydrodynamic force acting on the nasal extremity reaches a critical value, m ² ;

S _bp is the submerged area of the boule when the hydrodynamic force acting on the nasal extremity reaches a critical value, m ² ;

To _Z - safety factor.

In the proposed technical solution, when approaching the hydrodynamic force acting on the plane of the deck in the bow tip to the critical value, the boules separate, and the ship in the bow tip acquires the side obstruction and the inverse inclination of the stem, thereby reducing the hydrodynamic force acting on the deck when it is captured by the wave nasal tip, and eliminates the rollover of the vessel and the destruction of the main part of the hull, and the main part of the hull remains afloat while maintaining seaworthiness.

The accompanying drawings show:

in FIG. 1 - General view of the hull;

in FIG. 2 is a view B in FIG. one;

in FIG. 3 is a section AA in FIG. one;

in FIG. 4 is a section BB in FIG. one.

In the drawings, the following notation:

1 - part of the main body;

2 - buli detachable;

L is the length of the vessel, m

The hull structure of the vessel consists of an outer skin and a set of beams forming the main part 1 of the hull and detachable boules 2.

The hull operates as follows.

When the vessel is moving in strong oncoming waves, a periodic immersion of the bow tip may occur, which leads to the capture of the bow tip by the wave and the emergence of a complex mode of flow around the deck. Under such conditions, significant loads may occur, acting on the hull of the vessel, caused by the flow around the submerged deck, which can be considered as a wing of complex shape, located at an angle of attack to the incoming liquid flow. Under the influence of hydrodynamic force, the trim of the vessel will increase, and its stability parameters will sharply decrease [Burakovsky EP, Burakovsky P.E. Some problems of ensuring the general strength of ships in emergency situations // Transactions of the Krylov State Scientific Center. - Vol. 82 (366), 2014 - S. 21-30]. When approaching the hydrodynamic force to a critical value in the proposed design, detachable boules 2 will detach from the main body part 1, and they will remain afloat due to their waterproof design. With the detachable detachable boules 2 disconnected, the hydrodynamic loads acting on the main part 1 of the hull will decrease sharply due to the shape of the contours in the bow of the main part 1 of the hull for one third of the length of the vessel, which is characterized by obstruction and the opposite inclination of the stem. This form of the nasal tip of the main part 1 of the body will allow it to cut through the incident waves and avoid re-capture by the wave. This will provide an opportunity to ensure the safety of the crew, which will have time to make decisions on choosing the optimal mode of movement of the vessel in the port of refuge and the implementation of measures to improve its stability. The design of the closest analogue after separation of the nasal impermeable part in a storm with strong oncoming waves is characterized by unsatisfactory seaworthiness due to poor streamlining due to the presence of the aft impermeable part of the flat vertical surface in the nasal tip. This can lead to the rollover of the aft impermeable part or its destruction under the influence of shock waves in the flat vertical surface of its nasal tip. It should be noted that under normal operating conditions, not related to the impact of extreme hydrodynamic loads on the bow, in the proposed design, the presence of detachable boules 2 installed on the main part 1 of the hull ensures the collapse of the sides in the bow and the emergence of the vessel in a wave characteristic of the traditional design hulls of sea vessels.

To ensure timely disconnection of the detachable boules 2 from the main part 1 of the hull, the destruction of their connection should occur when the value of the hydrodynamic force is equal to a certain critical value P _cr corresponding to the maximum allowable drop in the metacentric height for a given vessel. Its value, as well as the immersed deck area of the vessel S, and, accordingly, the immersed area of the boules S _bp , can be estimated for each specific vessel using the apparatus of the theory of the ship in accordance with [Burakovsky EP, Burakovsky P.E. Some problems of ensuring the general strength of ships in emergency situations // Transactions of the Krylov State Scientific Center. - Vol. 82 (366), 2014 - S. 21-30].

To ensure the effectiveness of the proposed design, it is necessary that when approaching the value of the hydrodynamic force to the value of P _{cr, the} force acting on each of the boules 2 reaches the value of P _OD , at which they are separated from the main body part 1, taking into account the safety factor K _З. From this condition, you can determine the required value of the load P _OD , under the action of which the separation of the boules

where P _OT - load, the action of which causes the separation of the boule from the main part of the body, N;

P _cr - the critical value of the hydrodynamic force at which the vessel loses stability, if the separation of the boules is not provided for by the design, N;

S is the submerged deck area when the hydrodynamic force acting on the nasal extremity reaches a critical value, m ² ;

S _bp is the submerged area of the boule when the hydrodynamic force acting on the nasal extremity reaches a critical value, m ² ;

K _Z - safety factor.

To ensure unsinkability of the main body part 1 and detachable boules 2, they must be made in a waterproof design. The strength of the elements of the bow tip of the main part 1 of the vessel must satisfy the requirements for the side floors of the vessel in question, since after disconnecting the detachable boules 2, this part of the hull will be affected by loads comparable to those that act on the side floors.

It is possible to ensure separation of detachable boules 2 when the load reaches the value of P _dec due to the use of bolt and rivet joints, while the bolts or rivets must be cut off by the force arising when the force P _det . It is also possible to use welds, the strength of which should provide the perception of the upper part of the boule 2 force, not exceeding P _OD .

It should be noted that an excessive decrease in the value of _Psd can lead to an unacceptable decrease in the strength of the connection of the boules 2 with the main part 1 of the body and their separation during normal operation, not associated with extreme loads in the process of capture by the wave of the nasal extremity. To prevent such a situation, it may be necessary to implement measures that increase the values of P _cr , i.e. increasing the stability of the vessel. This will ensure sufficient strength of the hull and the effectiveness of the proposed design solutions.

Thus, the proposed design eliminates the loss of stability of the vessel during movement on oncoming waves in stormy conditions, as well as preserving its seaworthiness after the vessel leaves the capture by the wave due to the separation of previously provided structural elements, which contributes to the safety of navigation.

Claims (8)

The hull of the vessel, consisting of individual parts formed from the outer skin and the set beams in the form of separate impermeable shells connected by an integral connection, the strength of which is chosen so that the parts are connected until a critical value of the hydrodynamic force P _cr , which corresponds to the maximum allowable drop in metacentric height, is reached for this vessel, characterized in that it is composed of the main part, made with the reverse inclination of the stem and the obstruction of the side in the bow, and two parts made in the form of boules, forming a flat deck surface in the bow of the ship’s hull and providing camber, and the load P _dec , at which the boules will separate, is determined from the following relation:

Where P _OT - load, the action of which causes the separation of the boule from the main part of the body, N; P _cr - the critical value of the hydrodynamic force at which the ship loses stability, N; S is the submerged deck area when the hydrodynamic force acting on the nasal extremity reaches a critical value, m ² ; S _bp is the submerged area of the boule when the hydrodynamic force acting on the nasal extremity reaches a critical value, m ² ; To _Z - safety factor.

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