RU2740325C2 - Ship hull - Google Patents

Abstract

FIELD: vessels and other watercrafts.

SUBSTANCE: invention relates to the field of shipbuilding, in particular to the design of ship hulls. Disclosed is a hull, which is an impermeable shell consisting of thin sheets, which are supported by beams made from rolled or composite welded profiles, consisting of main part of body and boules. Boule on each side is made of separate parts, and total length of parts of boule makes at least one quarter of vessel length. Separate parts of boules are installed on axes fixed on fore end of housing with possibility of simultaneous pairwise rotation of opposed parts of boules.

EFFECT: due to limitation of value of hydrodynamic force acting on fore end of hull of vessel in conditions of storm at opposite wave, and prevention of tear-off of boules with occurrence of heeling moment, possibility of ship overturning is excluded, which increases safety of navigation.

1 cl, 5 dwg

Description

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

The known design of the forward part of the displacement type vessel (RU 2374120, IPC В63В 1/06, publ. 27.11.2009) with transverse symmetry about the central axis, and the forming lines of the hull increase in width from the baseline. The bottom is flat or has deadrise and passes into the bottom with a given bottom radius. From the bottom to a given height, the generating lines are slightly inclined outward. At the level of the tank deck, the outward-sloping line shape ceases and extends upward in a curved line back towards the center axis.

This design has the following disadvantages:

• the ship has a large windage;

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

• poor living conditions;

• impacts of waves can knock out windows in the wheelhouse and lead to damage to navigation equipment;

• at high wave heights, they can overlap over the superstructure, while the flat deck surfaces will facilitate the capture of the bow of the ship by the wave [Burakovsky EP, Burakovsky P.Ye. Some problems of ensuring the overall strength of ships in emergency situations // Proceedings of the Krylov State Scientific Center - Vol. 82 (366), 2014 - S. 21-30];

• poor germination on the wave, because due to the slenderness of the waterline, the ship crashes into the wave, and it twists over 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.

Known ship hull with a blockage of the side and a reverse inclination of the stem (US 6601529, В63В 3/00, publ. 05.08.2003).

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

Known ship hull, which is an impermeable shell, consisting of thin sheets, which are supported by beams made of rolled or composite welded profiles (Barabanov N.V. The design of the hull of sea vessels. L., Shipbuilding, 1981. - 552 p., P. 9-11, Figure 1).

This design has a significant drawback, which consists in the possibility of capturing the bow end by a wave, which is due to the presence of flat surfaces of the deck and the superstructure of the tank, as a result of which a drop in the metacentric height and the overturning of the vessel or the destruction of its hull may occur [Burakovsky E. P., Burakovsky P. E. Some problems of ensuring the overall strength of ships in emergency situations // Proceedings of the Krylov State Scientific Center - Vol. 82 (366), 2014 - S. 21-30]. The seizure of the bow by a wave means that when the deck is heavily flooded, it works in a submerged position as a wing, streamlined by a fluid flow, as a result of which a resultant pressure force arises on flat surfaces, which is determined by the angle of attack and the speed of the incoming fluid. This flow is unstable, as a result of which the resultant can at any time shift away from the center line and cause a strong heel or overturn of the vessel, as well as the destruction of its hull. Under the action of the resultant hydrodynamic forces, the trim of the ship increases, while a sharp decrease in the transverse metacentric height is observed, which contributes to the overturning of the ship.

As the closest analogue, the ship's hull is adopted, made in the form of an impermeable shell formed from the outer skin and beams of the set, moreover, the impermeable shell is made in the form of the main part of the hull, which has a side obstruction and a reverse inclination of the stem at the bow end, and boules forming a flat deck surface and ensuring the collapse of the side in the bow end, in addition, in the bow end of the main part of the hull there are hydraulic cylinders, the rods of which are connected to the boules, installed with the possibility of displacement towards the midship of the ship (RU 2672225, IPC В63В 1/06, В63В 43/02, published on 12.11.2018).

This design has a significant drawback, which is that significant hydrodynamic loads will act on the flat surfaces of the boules in a stormy sea on developed waves, which can lead to their separation from the main part of the hull. In this case, if one of the boules breaks off, the hull of the ship will become asymmetrical with respect to the centreline plane, as a result of which an additional heeling moment will act on the ship, which can lead to its overturning.

The invention solves the problem of increasing the safety of navigation in conditions of developed sea waves, by eliminating a situation in which an additional heeling moment may occur due to the separation of one of the boules from the main part of the hull, by changing the design of the boules and their fastening, as well as using the optimal length of the boules with the ability to avoid an increase in hydrodynamic loads.

To solve the problem in the hull of the ship, made in the form of an impermeable shell formed from the outer skin and beams of the set, in which the impermeable shell is made in the form of the main part of the hull, which has a side obstruction and a reverse inclination of the stem in the bow end, and boules forming a flat surface decks providing the collapse of the side in the bow end and installed with the possibility of changing the position relative to the main part of the hull, it is proposed to make the boules from each side from separate parts, and the total length of the boule parts to be made at least one quarter of the length of the vessel Separate parts of the boules are proposed to be installed on axles fixed on the nose end of the hull with the possibility of simultaneous pairwise rotation of oppositely located parts of the boules.

In the proposed technical solution, when the ship gets into unfavorable weather conditions, accompanied by flooding of the deck in the bow end and the emergence of the danger of being captured by a wave of the bow end, there is a pairwise rotation of the opposite parts of the boules relative to the axes at an angle of 90 °, as a result of which the load acting on the bow end is reduced, due to a sharp reduction in the deck area and due to an increase in resistance forces during the downward movement of the bow, the bow's burrowing into the wave decreases, which also helps to reduce the hydrodynamic loads acting on the deck in the bow.

The accompanying graphics show:

in fig. 1 - General view of the ship's hull in normal operation;

in fig. 2 is a general view of the ship's hull when parts of the boules are turned to prevent the bow of the ship from being caught by the wave;

in fig. 3 - section a-a in Fig. one;

in fig. 4 - section b-b in Fig. 2;

figure 5 - the time dependence of the length of the bow end of the ship hull immersed in water with a length of 168 m with a wave height of 5.6 m and a freeboard height of 2.9 m in conditions of capture by a wave of the bow end according to [Burakovsky E.P., Burakovsky P .E. On the question of determining the load acting on the deck of the ship in the bow when it is flooded in oncoming waves // Marine Intelligent Technologies - 2018 - No. 4 (42), vol. 3. - P. 19-25].

On graphic materials the following designations are adopted:

1 - main body part;

2 - part of the boule;

3 - axis;

L is the length of the ship's hull, m;

a - the length of the bow end of the ship's hull immersed in water, m;

t - time, s.

The structure of the ship's hull consists of the outer skin and beams of the set, forming the main part of the hull 1 and part 2 of the boules, which are fixed on the axes 3 with the possibility of rotation.

The ship's hull works as follows. In the normal operation of the vessel, when the waves do not reach the deck, parts 2 of the boule are in the initial position (Fig. 1, Fig. 3) and form a flat surface of the deck at the bow end. When the vessel moves in strong oncoming waves, the bow end may periodically sink into the water, which leads to the appearance of a complex flow around the deck. In such conditions, significant loads can arise that act on the deck of the ship's hull at the bow end, caused by the flow around the submerged deck, which can be considered as a wing of a complex shape located at an angle of attack to the oncoming fluid flow. Under the action of the hydrodynamic force, the trim of the vessel will increase, and the parameters of its stability will sharply decrease. In addition, there is an increase in stresses from the general bending, which can lead to the destruction of the ship's hull [Burakovsky EP, Burakovsky P.E. Some problems of ensuring the overall strength of ships in emergency situations // Proceedings of the Krylov State Scientific Center - Vol. 82 (366), 2014 - S. 21-30]. When a dangerous situation arises in the proposed design, at the command of the navigator or the onboard intelligent system, the opposite parts of the 2 boules are rotated in pairs (Fig. 2, Fig. 4). The length of the ship's hull, on which parts of the 2 boules are installed, must be at least one quarter of the length of the ship, which is determined from the condition that the bow of the ship is captured by the wave. With a smaller length of the body, on which parts of 2 boules are installed, their effectiveness will be insufficient, since according to the simulation results according to the methodology [Burakovsky EP, Burakovsky P.E. On the question of determining the load acting on the deck of the ship in the bow when it is flooded in the oncoming waves // Marine Intelligent Technologies - 2018 - No. 4 (42), vol. 3. - P. 19-25] when the bow of the ship is captured by the wave about a quarter of the length of the ship's hull is immersed in the water (Fig. 5). At the same time, an increase in the length of a boule in the construction of the closest analogue is limited by the fact that with an increase in size, significant hydrodynamic loads will act on it, therefore at least two parts of 2 boules should be installed from each side. This will reduce the loads acting on each of them and ensure reliable fastening of parts 2 of the boules to the main part of the body 1.

After the turn of the parts 2 of the boules, the hydrodynamic loads acting on the bow of the main part of the hull 1 will decrease due to the cutting wave of the shape of the bow of the main part of the hull 1, which is characterized by the side roll-over and the reverse inclination of the stem. In this case, the turn of the opposite parts of the 2 boules in the proposed design is accompanied by an increase in the resistance forces acting on the bow when it moves downward, which helps to reduce the ship's bow in the wave and, accordingly, to an even more significant decrease in the hydrodynamic loads acting on the bow when it flows around liquid.

To identify a dangerous situation in which there is a probability of capture by a wave of the bow end of the ship, and, accordingly, the need to turn parts of 2 boules, approaches to control the dynamics of the ship, set forth in [Burakovsky P.E., Nechaev Yu.I. Construction of an algorithm for controlling the situation of capture by a wave of the bow end of the vessel using the methods of the modern theory of catastrophes // Izvestia KSTU.- Kaliningrad: FGBOU VPO "KSTU", 2015 - №37. - S. 178-185]. In this case, the command to turn the opposite parts of 2 boules can be given both by the navigator and by the onboard intelligent system in automatic mode.

Thus, the proposed design makes it possible to reduce the hydrodynamic loads acting on the deck of the ship at the bow end in the developed head-on waves, in addition, the separation of boules is prevented, as well as the appearance of additional heeling moments when a boule breaks off one side and overturning of the vessel when moving on head-on waves in stormy conditions, which improves the safety of navigation.

Claims (1)

The hull of the ship, made in the form of an impermeable shell formed from the outer skin and beams of the set, in which the impermeable shell is made in the form of the main part of the hull, which has a side roll-over and a reverse inclination of the stem at the bow end, and boules forming a flat surface of the deck, providing the side roll-over in the bow end and installed with the ability to change position relative to the main part of the hull, characterized in that the boule on each side is made of separate parts, and the total length of the boule parts is at least one quarter of the length of the vessel, and the individual parts of the boules are installed on fixed on the bow body axles with the possibility of simultaneous pairwise rotation of oppositely located parts of the boules.

Images