JPS6319644B2 - - Google Patents

Description

[Detailed Description of the Invention] Traditionally, fenders have been installed to absorb energy when ships are berthing, but as ships have become larger, fenders with larger spring constants have been adopted.
This fully functions to absorb energy when the ship is berthed, but assuming that the ship is moored after berthing, the ratio of the spring constant of the fender to that of the mooring line is approximately 100 to 1000 times. When waves act on a ship, the ship's motion becomes extremely large. In addition, as ships become larger, the berthing energy of the ship also increases, but if a fender with a large spring constant attempts to absorb this berthing energy, a large reaction force will act on the mooring berth or pier itself, resulting in the strength of the berth, etc. is also quite necessary.

The present invention has been proposed in order to solve such problems, and a dart pot is attached to a fender provided at a floating body berthing part, and the energy when the ship berths is transferred to the spring displacement of the fender and the dart pot. The present invention relates to a floating body berthing device characterized in that it is configured to absorb fluid resistance.

In the present invention, as described above, the berthing device disposed at the berth of the floating body is configured with a fender and a doss pot, so that the energy at the time of berthing of the floating body is absorbed by the spring displacement of the fender, as in the conventional case. In addition, the fluid resistance of the dart pot absorbs the energy when the floating body approaches the shore, so the spring constant of the fender can be reduced, and the maximum reaction force generated on the quay can be reduced.

The present invention will be described below with reference to the illustrated embodiments.
Fig. 1 is a conceptual diagram of the present invention, where K is a fender constituting a kind of spring installed on the quay G at the berthing point of the ship S, and a doss pot D constituting a shock absorbing device is installed in parallel to prevent the berthing device of the ship. is configured.

By absorbing the berthing energy of the hull S by both K and D, the spring constant of the fender K is reduced, and the maximum reaction force generated on the quay G is reduced.

FIG. 2 shows an embodiment of the berthing device of the present invention,
A plurality of dart pots 3 are arranged around an elastic member 2a such as rubber of a fender 2 installed on a quay 1.

Incidentally, a large-sized dart pot may be provided in the expandable member 2a.

FIG. 3 is a chart in which the horizontal axis shows the ratio of the spring constants of the fender and the mooring line, and the vertical axis shows the absorbed energy that the fender should absorb when the ship approaches the shore.

As is clear from Figure 3, when the berthing device consists of only fenders, the amount of absorbed energy changes considerably depending on the fender's spring constant; This is because the added mass of the hull changes accordingly. Furthermore, if the spring constant is increased, the absorbed energy of the fender becomes smaller, which explains why the spring constant of the fender was conventionally increased as ships became larger.

On the other hand, when a dart pot is attached to the fender as in the present invention, the berthing energy is also absorbed by the fluid resistance of the dart pot, so the absorbed energy of the fender is small, as shown by the dotted line and the dashed-dotted line in FIG. It's over. Therefore, the spring constant of the fender may be reduced.

In addition, in Figure 3, the berthing speed of the ship = 1.94
cm/sec, = 15 cm/sec The local Kd is the attenuation coefficient of the dart pot, the chain double-dashed line shows the absorbed energy of the fender according to the Stelson equation, and the solid line shows the case of only the fender.

Figure 4 is a chart showing the distortion of the fender. The distortion is quite large, but by installing a dart pot, (Kd=0.041ton/s・m, Kd=
0.082ton/s・m) Distortion of the fender is also reduced.
This has the advantage of allowing the fender to be made smaller.

Figure 5 shows the maximum reaction force that acts on the quay or the ship's hull when berthed.The solid line shows the maximum reaction force when only the fender is used, and the dotted line shows the maximum reaction force when both the fender and dashpot are used together. It can be seen from this that the reaction force acting on the quay is smaller with the fender with a dart pot. If the maximum reaction force acting on the quay wall can be reduced in this way, the strength of the quay wall can be made smaller than before. Note that the berthing speed at this time is the same as in the cases of FIGS. 3 and 4.

As is clear from the above, using a berthing device that includes a dart pot and a fender,
Reducing the spring constant of the fender has many advantages when berthing.

In addition, not only when berthing, but also when the ship is moored, there is a subharmonic motion during swaying, in other words, the spring constant of the mooring line is smaller than that of the fender, and the asymmetry of the spring is large. This can significantly reduce the phenomenon in which large vibrations occur due to resonance at a period smaller than the natural period.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a floating berthing device according to the present invention,
Fig. 2 is a slope view showing an embodiment of the present invention, Fig. 3 is a chart showing the absorbed energy of the fender when berthing, Fig. 4 is a chart showing the distortion of the fender when berthing, and Fig. 5 is a chart showing the fender distortion when berthing. This is a chart of the maximum buoyant force acting on the quay and floating bodies. 2... Fuenda, 3... Datsushipot.

Claims (1)

[Claims] 1. A dart pot is attached to a fender provided at the berthing part of the floating body, and the energy when the ship berths is absorbed by the spring displacement of the fender and the fluid resistance of the dart pot. Floating berthing device.