JPH1199986A - Hull form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce wave making resistance, to save fuel cost, and to improve running speed, while insuring hold capacity and good cargo stacking by forming recessed grooves narrowing the width of a hull on the starboard side and the port side at the part of a load line. SOLUTION: Recessed grooves 12, 12 horizontally extending from the bow part to the stern part are formed on the side shell plating 3, 3 of the starboard and the port of a hull 1, and the load line 7 is set so as to be positioned in the recessed grooves 12, 12. The recessed grooves 12, 12 are spread extending over the full length of the parallel parts on both ship sides, the depth of the grooves is gradually made shallow on the positions approaching from the parallel part to the bow part and the stern part, and finally the grooves disappear. Even if the width B of the whole ship and the width/length of a cargo hold are set similar to a cargo ship having no recessed groove, the width (b) of the hull 1 at the load line 7 becomes narrower than the width B of the whole ship, generated waves become small, and the wave making resistance also becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hull shape of a cargo ship.

[0002]

2. Description of the Related Art Tonnage, which indicates the size of a ship, includes gross tonnage, loading weight tonnage, and drainage tonnage. Of these, the registration tax for ships, the port entry fee, etc. are used as the basis for calculation. It is a gross tonnage representing the total volume inside the hull. According to the Ship Related Law, this gross tonnage is, for example, 299 tons, 4
It is stipulated that the tax amount and the like increase each time a predetermined gross tonnage such as 99 tons or 699 tons is exceeded. Conventionally, therefore, especially in a cargo ship, in order to increase the capacity of the cargo hold as much as possible and to improve the cargo loading as much as possible within a range where the gross tonnage does not exceed the predetermined gross tonnage frame, the ship length L is divided. A hull shape having a wide width B (that is, a small value of L / B) is adopted.

[0003]

However, the resistance that hinders the navigation of a ship includes frictional resistance with water, wave-making resistance, eddy resistance, and air resistance. Depends on the hull L / B.
The larger the value, and the faster the cruising speed, the larger the value.
Therefore, in the case of the hull shape having a small L / B like the conventional cargo ship, the fuel consumption has to be increased due to the wave-making resistance, and in particular, sailing at a high speed according to the recent demand of the domestic shipping industry. In that case, soaring fuel costs became a serious problem.

The inventor of the present invention, who has conducted various studies on the reduction of wave making resistance, has found that the magnitude of the waves generated during cruising has a deep relationship with the width of the ship in contact with the water surface and is submerged in the water. We knew that it was not much affected by the ship's width, and completed the present invention. That is,
The present invention can reduce the wave-making resistance at full load while securing the cargo hold volume and good cargo loading,
It is an object of the present invention to provide a hull shape capable of reducing fuel cost and improving cruising speed.

[0005]

In order to achieve the above object, the hull shape according to the present invention is such that concave grooves are formed on the ship side on the starboard and port sides so as to reduce the width of the hull at the portion of the full load line. It is characterized by having.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7, reference numeral 1 denotes a hull of a cargo ship according to an embodiment of the present invention. Reference numeral 2 denotes an upper deck, 3 denotes a ship side outer plate, 4 denotes a ship bottom outer plate, 5 denotes a cargo hold, 6 denotes a bow valve, and 7 denotes a full load waterline. Also,
5 to 7, reference numeral 8 denotes a freeboard deck, 9 denotes an inner bottom plate,
Numeral 10 denotes a side wall of the cargo hold 5, and as shown in FIG. 5, the hull 1 has a double bottom structure. Plate 4 and inner bottom plate 9
In addition, ballast water (seawater) is accommodated in a ballast tank 11 formed between the ballast tank 11 and the side wall 10 to secure stability, and ballast water is discharged from the ballast tank 11 when the ship is fully loaded to secure a freeboard. It has become.

Further, on the starboard side and the port side of the hull 1 as described above, there are formed grooves 12, 12 extending horizontally from the bow to the stern, and the full load water line 7 is located in the grooves 12, 12. Is set to More specifically, as shown in FIG. 5, a sloping portion 3 a extending obliquely inward from a predetermined height position below the full load line 7 is provided on the hull 1 on the starboard side and the port side of the hull 1.
A vertical portion 3b rising vertically from the upper end of the vertical section 3a and an inclined portion 3c extending obliquely outward from the upper end of the vertical portion 3b are formed. Are formed.

[0008] As apparent from FIGS. 3 and 4,
At the center in the longitudinal direction of the hull 1, both the starboard and port sides continue in parallel at predetermined intervals. Further, at the bow portion and the stern portion following both ends of the parallel portion, the hull 1 is narrowed in a tapered shape in which the width becomes narrower as approaching the bow end or stern end, and becomes narrower in the vertical direction as approaching the ship bottom. . Each of the grooves 12 extends in the cross-sectional shape of FIG. 5 over the entire length of the parallel portion, and the depth of the groove gradually becomes shallower from the parallel portion to a point reaching the bow and stern. Has disappeared.

This will be described with reference to FIGS. 1, 6 and 7. In FIG. 6, which shows a cross section taken along the line C--C in FIG. 1, the lower part of the ship side outer plate 3 is directed inward as compared with FIG. As a result, the inclination of the inclined portion 3a is very close to the vertical, and is almost indistinguishable. further,
In FIG. 7, which shows a cross section taken along the line DD in FIG. 1, almost all of the ship side outer plate 3 except for the connection corner with the upper deck 2 is narrowed inward, and the concave groove 12 has completely disappeared. . Although not shown, the end of the groove 12 on the stern side has substantially the same shape.

In the hull 1 of this embodiment, the length (length between perpendiculars) L of the ship shown in FIG. 1, the width B of the whole ship shown in FIGS. 2 and 5, and the width and length of the cargo hold 5 are shown. Is substantially the same as that of a conventional cargo ship having no concave groove 12, because the concave groove 12 is formed as described above,
The width b of the hull 1 at the portion is smaller than the width B.

Therefore, when the boat is fully loaded, the water surface is
2 is substantially the same as increasing L / B to L / b, and the resulting wave is smaller than before, and the energy consumed to create the wave That is, the wave making resistance is also reduced. Therefore, if the cruising speed is the same, the engine output will be lower than before and the fuel consumption will be reduced, while if the engine output is the same, the cruising speed will be higher than before. In addition, the operating cost of the ship can be reduced.

Further, the provision of the concave groove 12 reduces the total volume inside the hull and reduces the total tonnage. Therefore, if the dimensions of the other parts are the same as those of the related art, the total tonnage frame specified by the ship-related law is applied. Leeway. (For example, 4
In the case of a 99 gross tonnage hull, a margin of about 60 to 80 m ³ is generated. Therefore, it is possible to increase the volume of the cargo hold 5 and the accommodation area (not shown) by diverting the volume of the generated margin. In addition, it is possible to increase the length L and the width B of the ship with a sufficient volume without increasing the volume of a specific portion such as the cargo hold 5 or the living quarters, thereby increasing the size of the entire ship. In this way, it is possible to increase the load weight in the same gross tonnage frame as compared with the related art.

The reduction of the total volume inside the hull can be achieved without reducing the weight of the cargo, particularly by forming the concave groove 12 to extend above the full load line 7. That is, in FIG. 5, if the hull shape is such that the concave groove 12 is larger than the full load line 7 and extends to, for example, the vicinity of the bottom of the ship, the drainage volume below the full load line 7 is reduced, and the load weight is reduced. However, in the hull 1 of this embodiment, as can be seen from FIG.
The lower end of 2 stops at a point slightly lower than the full load water line 7, and the hull 1 extends below the full load water line 7 to the width B, so that a drainage volume below the full load water line 7 is secured.

On the other hand, if the hull shape is such that the upper part of the concave groove 12 extends to the connection corner between the ship-side outer plate 3 and the upper deck 2, the upper deck 2 between the cargo hold 5 and the ship side is formed. The width becomes narrow, and the width of the passage provided here becomes narrow, which causes a problem that it becomes difficult to pass. On the other hand, in the hull 1 of this embodiment, the upper end of the concave groove 12 stops at a position slightly lower than the upper deck 2, and the hull 1 expands to a width B above the upper end. Is also secured.

By the way, it goes without saying that the technical scope of the present invention is not limited to the above embodiments, and for example, the cross-sectional shape of the concave groove, the amount of depression, etc. are arbitrary. In the above description, the present invention is applied to a cargo ship. However, the present invention can be applied to a ship other than a cargo ship, such as a passenger ship.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The hull shape of the present invention is applied to 499 gross tons,
A cargo ship with a payload of 1600 tons and a maximum engine output of 1800 ps was designed. The hull shape is almost the same as the above drawing,
The dimensions shown in the figure are as follows. L = 70.00 m B = 12.20 mb = 11.70 m Further, for the concave groove 12, the distance from the full load draft line 7 to the lower end of the vertical portion 3 b of the hull outer panel 3 is 610 mm, and the distance from the full load draft line 7 to the hull outer panel. The distance to the upper end of the vertical portion 3b is 1
Each was set to 885 mm.

Based on this design, a model ship having a vertical line length of 2.00 m is manufactured, and for comparison, the gross tonnage, the loading weight tongue, the engine maximum output, etc. A conventional hull-shaped model ship with no hull shape was manufactured, and a water tank test was performed on each model ship, and various resistance values and waveforms in a fully loaded state were examined.

As a result, the magnitude of the waves generated on the water surface of the water tank was clearly smaller in the hull shape of the present invention.

Further, as is apparent from the graph of FIG. 8 showing a comparison of the shaft horsepower with the ship speed estimated from the results of the tank test, the shaft horsepower required to obtain a predetermined ship speed in the conventional hull shape is as follows. For example, 1250p at 12 knots
s, 1800 ps at 13 knots, whereas the hull shape of the present invention has 974 ps, 13 knots at 12 knots.
At knots, the power consumption is reduced to 1324 ps, and the required horsepower is reduced by 22 to 26% compared to the conventional case, so that it can be seen that a proportional reduction in fuel cost can be expected.

Looking at the ship speed with respect to the shaft horsepower, the conventional hull shape shows 11.75 knots at 1126 ps,
At 12.11 knots at 1611 ps,
The hull shape of the present invention is 12.50 knots at 1126 ps and 13.50 knots at 1611 ps, so that the speed can be increased by about 0.7 to 0.8 knots with the same horsepower, and the time required to reach the destination is reduced. Was found to be expected.

[0021]

As described above, in the hull shape according to the present invention, concave grooves are formed on the ship side on the starboard and port sides so as to reduce the width of the hull at the full load water line, Since the water surface is located in the groove, the L / B of the hull is substantially the same as that of the hull, and the generated waves are smaller than before and the wave resistance is also smaller. Therefore, the fuel cost can be reduced and the cruising speed can be improved.

The provision of the concave groove reduces the volume of the hull, that is, the gross tonnage. By allocating the reduced volume, the cargo hold or the accommodation area can be set within the gross tonnage stipulated by the Ship Related Law. It is possible to increase the capacity as compared with the conventional case, and it is also possible to increase the length and width of the whole ship without increasing the volume of the specific portion, and to increase the loading weight in the same gross tonnage frame.

[Brief description of the drawings]

FIG. 1 is a side view of a cargo ship to which a hull shape of the present invention is applied.

FIG. 2 is a front view of the cargo ship.

FIG. 3 is a plan view of the cargo ship.

FIG. 4 is a schematic cross-sectional plan view of a cargo ship showing a plane shape crossing at the height of a full load line.

FIG. 5 is an enlarged sectional view of the cargo ship along the line AA in FIG. 1;

FIG. 6 is a schematic enlarged sectional view of the cargo ship taken along the line CC of FIG. 1;

FIG. 7 is a schematic enlarged sectional view of the cargo ship along the line DD in FIG. 1;

FIG. 8 is a graph showing a comparison of the shaft horsepower with respect to the boat speed estimated from the result of the tank test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hull 3 Ship side outer plate 7 Full load line 12 Concave groove

Claims (1)

[Claims] 1. A hull shape characterized in that concave grooves for reducing the width of the hull at a portion of the full load line are formed on the ship side on the starboard side and the port side.