JP2003165484A - Hatch coaming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a bracket in four corners of a hatch coaming. <P>SOLUTION: In this hatch coaming 6 having an opening in an upper deck of the hull, edge material side plates 6a and 6b of the coaming 6 and an upper deck back plate member 4 are arranged in nearly one straight line in the vertical direction, and a corner part 6c is formed into an arc shape, separating from a corner part 4e of the upper deck back plate member 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hatch combing structure of a ship such as a container ship and a bulk carrier having a large opening on the upper deck of a ship.

[0002]

2. Description of the Related Art In a cargo ship such as a container ship and a bulk carrier, a large deck opening is required for loading and unloading cargo, and this opening is called a hatch opening. Hatch openings are dangerous to leave open, so provide combing and covers as required by regulations. The hatch opening on the upper deck is provided with a hatch coaming with a height of 600 mm or more to prevent the inflow of waves and is covered with a steel watertight hatch cover. The size of the hatch combing is 10 m to 20 m in length, 10 m to 20 m in width, and 0.76 m to 1.5 m in height. According to the ship classification rules (NK), if the shape of the hatch opening corner of the upper deck is an arc with a radius of 600 mm or more, reinforcement such as thickening of the upper deck is not necessary.

FIG. 2 is a perspective view of a conventional hatch combing. In the figure, 1 is an upper deck, 2 is a hatch opening, and is a square opening whose corners are arcs with a radius R. 3 is hatch combing. The inner surface of the hatch coaming 3 is a quadrangle slightly larger than the hatch mouth 2 as shown in the figure. 4 is a back member of the upper deck. A vertical edge material side plate 3a of the hatch coaming 3, a vertical upper deck back member 4a, and a lateral edge material side plate 3b of the hatch coaming 3.
The upper deck back member 4b in the horizontal direction is welded to the upper surface and the lower surface of the upper deck 1 so as to be aligned in the vertical direction. Reference numeral 5 denotes a bracket, which has a right-angled triangular shape, and has a vertical bracket 5a on the extension line of the vertical edge member side plate 3a of the hatch coaming 3, and a horizontal bracket 5b on the extension line of the horizontal edge member side plate 3b. It is fixed.

Due to waves, the hull is subjected to a vertical bending moment and a horizontal bending moment. Especially, the vertical bending moment is large. Regarding the upper deck 1, this vertical bending moment of the hull is mainly carried by the upper deck back member 4a in the longitudinal direction. For the portion with the hatch coaming 3, the height of the cross section relating to the hull longitudinal bending moment is as follows: the height of the edge material side plate 3a of the hatch coaming 3, the thickness of the upper deck 1, and the longitudinal upper deck backing member 4a. While the heights are added together, the height of the cross section related to the vertical bending moment is the upper deck 1 in the portion without the hatch coaming 3.
And the height of the upper deck back member 4a in the vertical direction are added together. Therefore, in the portion with and without the hatch coaming 3, the section modulus related to the bending moment changes abruptly discontinuously, and a large stress concentration occurs at the boundary, which causes damage. The bracket 5 is provided to reduce such stress concentration.

According to the "Research Report on the Reasonable Hull Structure of Bulk Carriers" disclosed on the website of the Nippon Foundation Business Results Library / Japan Shipbuilding Association, "the category with the largest number of damages is hatch." Combing: Damaged part is side combing (edge material side plate 3a in the vertical direction in Fig. 2)
Most of the brackets are at the ends, and the main cause is the vertical bending of the hull. As described above, the portion of the bracket 5 is easily damaged. Therefore, while paying attention to the welding procedure of the bracket 5, the length of the bracket 5 in the vertical direction can be increased to reduce the angle of depression, but it will obstruct traffic, increase the material cost, and reduce drainage. There are drawbacks. The drain hole must be opened to improve drainage, but this drain hole is also easily damaged by stress concentration. Further, the bracket 5 may adversely affect the upper deck back member 4.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above problems of the prior art. By making the corners arcuate, the bracket can be eliminated and the adverse effect of the bracket can be eliminated. It is intended to provide hatch combing.

[0007]

In order to achieve the above object, the hatch coaming of the present invention is a hatch coaming of a ship having an opening on the upper deck of the hull, and includes a side plate of the edge material of the combing and an upper deck backing member. Are arranged in a substantially straight line in the vertical direction, and the corners are arcuate apart from the corners of the upper deck back member.

The radius of the arc is 400 to 1,000 m.
It is preferably m. This is because if the radius is too small, the effect will be reduced, and if it is too large, it will interfere with cargo handling.

Next, the operation of the present invention will be described. In general, damage is often generated from a welded joint, and if there is a square welded structure of hatch coaming in the high stress portion of the hatch opening corner of the hull, the structural strength is further reduced due to stress concentration. In the past, measures such as mounting brackets and additional welding were taken to avoid stress concentration. By making the corners arcuate, the stress concentration of the hatch combing can be avoided, and the welded part of the hatch combing body can be kept away from the corner of the upper deck backing member.

When a ship travels in the same or opposite direction to the traveling direction of waves and the wavelength of the waves coincides with the length of the ship, it undergoes a large vertical bending. That is, when the bow and stern are located at the crest of the wave and the center of the ship is located at the trough of the wave, the ship is subjected to the same bending moment as the beam with both ends supported by a uniform load, and conversely the bow and stern. Is located in the valley of the waves,
When the center of the ship is located on the mountain of waves, the ship is subjected to a central supporting yajirobe-like bending moment. Such a vertical bending moment of the hull is also applied to the upper deck, but in the upper deck, this moment is mainly carried by the upper deck lining member in the vertical direction.

Now, considering a portion having hatch coaming above the upper deck back member, the edge material side plates other than the corners are provided in a straight line above the upper deck back member. Therefore, the height of the cross section related to the vertical bending moment of the hull is the sum of the height of the edge material side plate of the hatch coaming, the thickness of the upper deck and the height of the upper deck backing member, and the hatch at the corner. After the combing is separated laterally from above the upper deck back member, the height of the cross section relating to the longitudinal bending moment of the hull is the sum of the thickness of the upper deck and the height of the upper deck back member. Therefore, the difference in the section modulus between the two is large.

In the plan view near the corner portion of the hatch coaming, in the straight portion of the hatch coaming, the edge material side plate is completely overlapped with the upper deck back member. When entering the corner, the inner surface of the combing gradually begins to move inward from the inner surface of the upper deck back member, and the outer surface of the combing gradually begins to move inward from the outer surface of the upper deck back member. Then, when the outer surface of the combing is separated from the inner surface of the upper deck back member inward, the hatch combing is completely separated from the upper deck back member. During this time, the shape of the part where the hatch coaming overlaps with the upper deck backing member on the plan view is that the width of the base end is the same as the thickness of the edge material side plate of the combing and the tip width is surrounded by arcs and chords that are zero. It has a triangular shape.

Considering a state in which a moment similar to that of a support beam with a uniform load is applied to the hull, the hatch combing and the upper deck back member are substantially triangular portions in a plan view where the hatch combing and the upper deck back member overlap each other in the plan view. If the force acting on the hatch combing is applied to the centroid of the substantially triangular shape, an upward eccentric load will be applied to that portion of the hatch combing. Therefore, that part of the hatch coaming is tilted inward, which makes the upper deck backing easier to bend upwards. In this way, the restraint force of the hatch coaming that restrains the upper deck back member from bending due to the hull vertical bending moment gradually decreases at the corners, so stress concentration is relieved.

As described above, since the stress concentration due to the hull longitudinal bending moment does not occur at the arc-shaped corner portion, the bracket described above as the prior art becomes unnecessary. Therefore, damages such as cracks generated in the bracket are eliminated, the material cost is reduced by the amount of the bracket, drainage is improved, and obstacles in passage are reduced. Further, in the conventional hatch coaming, a load is accumulated on the deck inside the corner portion of the combing, but when the corner portion of the combing is formed into an arc shape, the load is eliminated.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Ships such as container ships and bulk carriers have large openings on the upper deck for cargo handling, and the openings are called hatch openings. Combing and hatch covers are provided at the hatch mouth. FIG. 1 is a perspective view of the hatch combing of the present invention. In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals,
A duplicate description will be omitted. Reference numeral 6 denotes the hatch coaming according to the present invention, which includes a vertical edge material side plate 6a and a horizontal edge material side plate 6
b and four arc-shaped corner portions 6c. The hatch combing 6 is fillet welded to the upper surface of the upper deck 1.
The inner surface of the hatch combing 6 is slightly larger than the opening of the hatch opening 2 so that the fillet welding margin inside the combing 6 can be removed. The vertical edge material side plates 6a are arranged in a straight line in the upward direction of the vertical upper deck back member 4a, and the horizontal edge material side plates 6b are arranged in a straight line in the upward direction of the horizontal upper deck back member 4b. The four corners are arcuate apart from the corners 4e of the upper deck back member 4.
The radius R of the arc is preferably 400 mm to 1,000 mm. If the radius R is too small, the effect of forming an arc is reduced, and if it is too large, it interferes with cargo handling.

Next, the operation of this embodiment will be described. In general, damage often occurs from a welded joint, and if there is a square welded structure of the hatch coaming 6 in the high stress portion at the two corners of the hatch mouth of the hull, the structural strength is further reduced due to stress concentration. Conventionally, bracket 5 to avoid stress concentration
Measures were taken such as attaching a wire and increasing welding. By making the corners arcuate, stress concentration in the hatch coaming 6 can be avoided, and the welded portion of the main body of the hatch coaming 6 also has a corner 4 of the upper deck backing member 4 around the hatch mouth 2.
can be kept away from e.

Considering now the portion where the hatch coaming 6 is located above the upper deck backing member 4, the edge material side plates 6a other than the corners 6c are provided in a straight line above the upper deck backing member 6a. Therefore, the height of the cross section relating to the vertical bending moment of the hull is the sum of the height of the edge material side plate 6a of the hatch coaming 6, the thickness of the upper deck 1, and the height of the upper deck backing member 4a, After the hatch coaming 6 is separated laterally from above the upper deck backing member 6a at the corner portion 6c, the height of the cross section relating to the vertical bending moment of the hull is the thickness of the upper deck 1 and the height of the upper deck backing member 6a. Is the sum of. Therefore, the difference in the section modulus between the two is large.

FIG. 3 shows a corner portion 6 of the hatch combing 6.
It is a plan view of the vicinity of c, and in the figure, in the straight part of the hatch coaming 6, the edge material side plate 6a completely overlaps the upper deck back member 4a. When entering the corner portion 6c, the inner surface 6d of the corner portion 6c of the combing 6 becomes the inner surface 4 of the upper deck back member 4a.
The outer surface 6e of the corner portion 6c of the combing 6 starts to gradually separate inward from the outer surface 4d of the upper deck back member 4a. The outer surface 6e of the corner portion 6c of the combing 6 is the inner surface 4c of the upper deck back member 4a.
The hatch combing 6 completely separates from the upper deck backing member 4a when separated from the inside. During this time, in the plan view, the portion where the hatch combing 6 and the upper deck back member 4a overlap (see FIG.
The hatched portion) has a substantially triangular shape surrounded by a circular arc and a chord, the width of the base end portion of which is the same as the thickness of the edge material side plate 6a of the combing 6, and the tip width of which is zero.

Considering a state in which a moment similar to that of a support beam with uniform load is applied to the hull, the hatch coaming 6 of the corner portion 6c of the hatch coaming 6 and the upper deck back member 4a overlap each other in a plan view. If the force acting on the hatch coaming 6 at the portion (hatching portion) is applied to the centroid 7 of the substantially triangular shape, if it is applied to that portion of the hatch coaming 6, an upward eccentric load shown by an arrow 8 in FIG. 4 is applied. It will be. 4 is a sectional view taken along the line AA of FIG. Therefore, that portion of the hatch coaming 6 is tilted inward as shown by the dotted line in FIG. 4, whereby the upper deck back member 4a is easily bent upward. In this way, the restraint force of the hatch coaming 6 that restrains the upper deck backing member 4a from bending due to the hull vertical bending moment gradually decreases at the corner portion 6c, so that stress concentration is relieved.

As described above, since the stress concentration due to the hull vertical bending moment does not occur at the arc-shaped corner portion 6c, the bracket 5 described above as the prior art becomes unnecessary. Therefore, damage such as cracks generated in the bracket 5 is eliminated, the material cost is reduced by the amount of the bracket 5, drainage is improved, and obstacles to traffic are reduced.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0022]

As described above, according to the hatch combing of the present invention, since the corner portions are arcuate and the conventional bracket is eliminated, the conventional bracket is not damaged. Therefore, the material cost and the processing cost for the bracket can be reduced, the drainage can be improved, and the obstruction of traffic can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of the hatch combing of the present invention.

FIG. 2 is a perspective view of a conventional hatch combing.

FIG. 3 is a partial plan view of a corner portion of hatch coaming.

4 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 Upper deck 2 hatch mouth 4 Upper deck back member 5 bracket 6 Hatch combing 6a, 6b Edge material side plate 6c Corner part

Claims (2)

[Claims] 1. A hatch coaming for a ship having an opening on an upper deck of a hull, wherein a side plate of edge material of the combing and a back member of the upper deck are arranged substantially vertically in a straight line, and a corner portion is an upper deck. Hatch combing characterized by being arcuate away from the corner of the backing member. 2. The radius of the circular arc is 400 to 1,000 m
The hatch combing according to claim 1, wherein m is m.