JPS62214091A - Recovery vessel for water surface floating substance - Google Patents

Abstract

PURPOSE:To improve the recovery rate for the oil and dusts which float on the water surface by increasing the water depth at the water passage bottom part outside the contour part of a water passage bottom than the water depth of the contour part, thus markedly reducing the triangular waves and preventing the concentration of the wave energy. CONSTITUTION:At the bow part 1 of a vessel for recovering the water surface floating substances, the contour part 2 of a water passage bottom is installed, and the part 3 of the water passage bottom outside the contour part 2 is installed. When the contour of the contour part 2 of the water passage bottom is represented by a straight line, the water depth at the part departing by thetafrom the both outer sides in a bow angle 2beta is set h1, and the water depth at the rest part 2 (beta-theta) is set h2 larger than h1. The acute angle gamma can be set at 90 deg. by properly selecting beta, theta, h1, and h2, and the wave direction line 7 can be set nearly parallel to the hull center line 4. Thus, generation of large waves having the abnormally large wave height due to the concentration of wave energy or the superposition of waves in a hull water passage can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vessel for collecting objects floating on the water surface, and more particularly to the shape of the bow of a recovery vessel for floating objects on the water surface, such as an oil recovery vessel or a garbage recovery vessel. be.

2. Description of the Related Art A conventional single-hull oil recovery bow or garbage recovery vessel has a structure as shown in FIG. The upper figure in FIG. 3 shows a side view, and the lower figure shows a plan view.

That is, as shown in FIG. 3, a boat light a has an opening from which an inboard waterway C is guided through a collector d to the bottom e or side of the boat. In this type, there is a double door (f) at the opening of the bow (a), and when this door is closed, the outside has a smooth bow shape, but when it is opened, the shape is triangular and flat, as shown in Figure 3. The bottom g of the waterway protrudes below the water surface. In FIG. 3, g' indicates the outline of the waterway bottom g, i indicates the side wall of the inboard waterway C, and j indicates the center line of the ship.

Problems to be Solved by the Invention Conventionally, when the recovery ship shown in Figure 3 worked in waves, the waves entering the ship's internal waterway C formed very high triangular waves within the ship's internal waterway C, causing floating oil and There was a problem in that it reduced the garbage collection rate.

This is because the cause of the triangular waves was unknown, so no care was taken when determining the shape of the waterway bottom g that protruded below the water surface at the bow a. The present invention attempts to solve these problems.

Means for Solving the Problems The present inventor investigated the state of waves entering the inboard waterway C by applying waves from the bow a using a model ship, and then compared calculations and experiments for a waterway bottom with a simple outline shape. As a result, there was good agreement between the two, and the following findings were found.

First, triangular waves are generated even when the door f, which has been opened to the left and right, or the side wall j of the inboard waterway C is removed. From this, the generation of triangular waves is not due to the influence of these two.

Second, as shown in FIG. 4, the incident wave W has a wave crest line perpendicular to the direction of travel of the ship. A rapid change in water depth due to a channel bottom protruding into the water.

), the wave crest line W1 is bent at the contour g' of the waterway bottom g, and the wave crest line W1 travels at an acute angle γ with the hull center line j. For this reason, waves are superimposed or energy is concentrated on the hull centerline J, and a triangular wave is generated. In Fig. 4, co is the speed of the wave advancing toward the ship, Lo is the wavelength, Ho is the wave height, C1 is the speed of the wave entering the waterway bottom g, Ll is the wavelength, and ■ is the wave height. It shows the wave height.

Thirdly, when the contour g' of the channel bottom g is a straight line, the refraction calculation shows that the refraction is parallel to the wave direction line W, as shown in FIG.
w;>, the wave height increases due to the superposition on the hull centerline j, and the waveform propagates backward. And the concentration of wave energy does not occur.

Fourth, when the contour g' of the waterway g is convex outward as shown in FIG. 6, the wave direction kwo is refracted (w
', > Then, the wave energy is concentrated at a certain point.

Fifth, since a normal bow shape can be roughly represented by a combination of circular arcs and straight lines, it exhibits a phenomenon that is a combination of FIGS. 5 and 6.

Therefore, in the present invention, the water depth distribution is changed so that the water depth of the portion of the channel bottom other than the contour portion is greater than the water depth of the contour portion of the channel bottom.

An incident wave whose wave direction line is parallel to the hull centerline is refracted at the contour of the waterway bottom, and then the wave direction line becomes almost parallel to the hull centerline again at the water depth change area of the waterway bottom. Since the beam is refracted, it is possible to prevent wave overlap or energy concentration.

Embodiment FIG. 1 shows a first embodiment of the invention L7, and FIG. 2 shows a second embodiment of the invention. Also, the upper figure in Figure 1 is a plan view, and the lower figure is a cutting M! FIG. 3 is a cross-sectional elevational view taken along A-A. Similarly, the upper view of FIG. 2 is a plan view, and the lower view is a cross-sectional elevational view taken along section line B--H.

In Figure 1, 1 is the bow of the vessel for collecting floating objects on the water surface, 2
3 is the contour of the waterway bottom provided at the bow l, 3 is the portion of the waterway bottom other than the contour 2, 4 is the center line of the hull, 5 is the wave direction line of the incident wave, and 6 is the refracted wave described later. , 7 is the wave direction line of the subsequent wave, 8 is the crest line of the wave, and 9 is the water surface. Further, hl is the water depth of the contour section 2 from the water surface 9, h2 is the water depth of the waterway bottom part other than the contour section 2, and β
is 1/2 of the bow angle, θ is the angle of the water depth h□, and α is α. is the outer incident angle, C1 is the refraction angle, nl is the refractive index,
α1o is the incident angle in the field between the water depths h1 and h2, C2 is the refraction angle in the field, and n2 is the refractive index in the field.

That is, FIG. 1 shows a case where the contour of the contour portion 2 of the waterway bottom is a straight line. The portions of θ from the outside of the plane of the bow angle 2β are set to the same water depth h1 as in the conventional case, and the remaining portions 2 (β-β) are set to a water depth h2 greater than the water depth h1.

By doing this, due to the principle of wave refraction,
The following formula holds.

sinα, = :, sinαo ==, cosβ
α1o-α, 108inα,, knee 51na,.

, '-81nα2=” ((!08βCO81!' +
n, 81nl! l ) 1n2 trench From Figure 1, γ = α2 + β - θ However, here, the wavelength of the Lo two-person radiation wave is: the wavelength of the refracted wave at the outer contour L2 : the wavelength at water depth h2 The above n1 and n2 are the water depth h1 and Because it will be decided by h2,
By appropriately selecting β, θ, hl, and h2, γ can be made approximately 90 degrees, that is, the wave direction line 7 can be made approximately parallel to the hull centerline 4. FIG. 1 shows an example of this.

Figure 2 shows the case where the outline of the contour part 2 of the waterway bottom is a circular arc.
By changing the water depth distribution as shown in 2, the wave direction line 7
It is possible to prevent the generation of waves with abnormally large wave heights due to concentration of wave energy or superimposition of waves in the ship's waterway by aligning the waves parallel to the hull centerline 4.

Effects of the Invention The present invention provides a contoured portion of the waterway bottom and a portion other than the contoured portion of the waterway bottom so that the water depth of the portion of the waterway bottom other than the contoured portion is greater than the water depth of the contoured portion of the waterway bottom provided at the bow. Since the water depth distribution from the water surface changes between the waterway bottom and the waterway bottom, at that contour, incident waves with wave direction lines parallel to the hull centerline are refracted toward the hull centerline. ,
The water depth distribution of the waterway bottom part other than the contour part causes the wave direction line of the refracted wave to be refracted almost parallel to the hull centerline, and therefore, the wave direction line of the refracted wave is refracted almost parallel to the ship's hull centerline, which tends to occur in the ship's internal waterway. It can significantly reduce delta waves, prevent concentration of wave energy, and increase the recovery rate of oil and debris floating on the water surface, and can be achieved by a simple change in the shape of the bow.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the first embodiment of the present invention, Fig. 2 is an explanatory diagram also showing the second embodiment, Fig. 3 is an explanatory diagram of the conventional technology, and Fig. 4 is the bow channel bottom. FIG. 5 is an explanatory diagram of wave refraction when the contour of the waterway bottom is a straight line, and FIG. 6 is an explanatory diagram of wave refraction when the outline of the waterway bottom is an arc. DESCRIPTION OF SYMBOLS 1... Bow part, 2... Outline of waterway bottom, 3... Portion of waterway bottom other than the outline, 4... Hull center line, 5
... wave direction line of the incident wave, 6... wave height line of the refracted wave,
7... Further wave direction line, 8... The wave crest line,
9...Water surface. Figure 5

Claims (1)

[Claims] 1. In a single-hulled water surface floating object recovery vessel equipped with an inboard waterway having a waterway bottom that communicates with an opening provided in the bow and has a waterway bottom that protrudes below the water surface, the water depth is greater than the water depth of the contour of the waterway bottom. A vessel for collecting floating objects on the water surface, characterized in that the water depth at the bottom of the waterway other than the contour area is increased.