JP4820393B2 - Bilge keel - Google Patents

Description

  The present invention relates to a structure of a bilge keel disposed at the lower part on both sides of a ship.

  Generally, a ship is provided with a member called a bilge keel on the bottom ship side in order to suppress rolling. This type of bilge keel includes a so-called split type bilge keel that is divided into a plurality of parts in the vertical direction of the hull, in addition to a continuous type that is also referred to as a continuous type that is continuously provided in the vertical direction of the hull. FIG. 8 is a hull side view schematically showing a conventional continuous bilge keel. In FIG. 8, reference numeral 100 denotes a ship, 101 denotes a continuous bilge keel, and 102 denotes a propeller.

As the above-mentioned continuous type bilge keel, for example, the one disclosed in JP-T-2004-513830 is known, and as the above-mentioned split type bilge keel, for example, Japanese Utility Model Laid-Open No. 61-138792 (actual application S60-022689). One disclosed in “Retractable Bilge Keel Device”) is known.
The bilge keel disclosed in JP-T-2004-513830 is related to the invention name "High-efficiency bilge keel", and "Since it has a simple shape and its length is limited, it reduces the roll motion on ships. In view of the fact that it cannot play such a large role (see paragraph number 0003 of the same gazette specification), the ship's roll motion is provided by providing bilge keels with various shapes on ships, marine structures and FPSOs that are slow in speed. For the purpose of providing a highly efficient bilge keel that can be greatly reduced (see paragraph number 0004 of the publication), it is provided so as to protrude outside the extension line of the width and bottom surface (see claim 1) or A structure having a triangular or circular cross-sectional shape is connected to the end of the bilge keel (refer to claims 2 and 3). The was maximally suppressed, achieving an improvement in exercise performance is obtained by such an effect, such as "may be to help the ship design and interpretation (see the publication specification paragraph number 0017).

  Further, the bilge keel disclosed in the Japanese Utility Model Application No. 61-138792 (actual application S60-022689) relates to the devised name “retractable bilge keel device”, and in the case of navigating a relatively calm sea,・ ・ Problems to reduce propulsion performance due to increased resistance ... A retractable bilge keel device that can reduce both hull roll and prevention of propulsion performance. For the purpose of "providing" (see page 3, lines 3 to 14 of the same publication), "the hull curved part that connects the bottom of the hull and both sides of the hull is divided into a plurality along the length of the ship. And a concave portion is formed in the curved portion of the hull to store the bilge keel, and a base end portion of the bilge keel is pivotally attached to one side of the concave portion, By adopting the configuration of “A bilge keel rotation drive mechanism is provided” (see the claims of the utility model registration in the publication), “the simple configuration has the advantage of reducing hull roll and preventing propulsion performance from being reduced. The effect of "obtained" is achieved (see page 7, line 12 to page 8, line 2).

That is, the bilge keel disclosed in Japanese Utility Model Publication No. 61-138792 (actual application S60-022689 “Retractable Bilge Keel Device”), as shown in FIG. 9, “connects the bottom of the hull and the sides of both ships, respectively. `` It is divided into a plurality of parts along the length of the ship along the length of the ship's curved part '', and further, `` a recess is formed in the above-mentioned curved part to store the bilge keel, and the bilge keel The base end portion is pivotally attached, and the rotational drive mechanism of the bilge keel is provided. FIG. 9 is a diagram showing an outline of the conventional retractable bilge keel device disclosed in FIG. 2 of Japanese Utility Model Laid-Open No. 61-138792. The bilge keel 110 includes a motor (not shown), a bevel gear and a shaft. A bilge keel rotation drive mechanism (not shown) such as 103 is provided.
Special table 2004-513830 gazette Japanese Utility Model Publication No. 61-138792

However, the continuous bilge keel that is integrally provided on the ship side disclosed in the above Japanese translation of PCT International Publication No. 2004-513830 has a problem that is unique to the continuous bilge keel. There is a problem of getting worse. Further, as disclosed in Japanese Utility Model Laid-Open No. 61-138792, the split-type bilge keel can be stored as appropriate, but has a problem that it has a complicated structure and has a drive unit, which may cause a failure.
In view of the above problems, an object of the present invention is to provide a bilge keel having a simple structure and good propeller propulsion efficiency.

In view of the above-mentioned object, the invention according to claim 1 of the present application is a bilge keel that is constructed and arranged separately for each block of a ship in the bilge keel, each of which has a substantially trapezoidal bilge keel from the center of the ship to the front and rear. 20-30% in both bilge central portion of the ship to the length of Lpp and spaced for each block, and 20% position after from the stern of the bilge keel 20% position from the bilge keel or stern uppermost stern The mounting angle of this part to the hull is tilted so that the rear side is upward as seen from the ship side direction.
The invention according to claim 2 of the present application is the bilge keel according to claim 1, wherein, among the divided bilge keels, the stern bilge keel or the bilge keel located at a position 20% from the stern is located. The angle of attachment to the hull is perpendicular to the curved portion from the ship side to the bottom of the ship, and the angle of attachment to the hull of the stern bilge keel or the part after the bilge keel located 20% from the stern is The mounting angle on the bottom side of the ship is an obtuse angle inclined upward with respect to the curved portion.
The invention according to claim 3 of the present application is the bilge keel according to claim 1, wherein, among the divided bilge keels, from the stern of the stern bilge keel or the stern of the bilge keel located 20% from the stern as viewed from the ship side. The mounting angle of the portion after the 20% position to the hull is an angle at which the water flow behind the bilge keel flows into the upper end of the propeller.

Since this invention is comprised as mentioned above, there exists the following effect.
By adjusting the angle of the stern of the bilge keel so that the water flow behind the bilge keel flows to the upper end of the propeller, the structure is simple, the propeller propulsion efficiency is improved, and the horsepower is reduced.

  An embodiment of a bilge keel according to the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side view of a bilge keel according to a first embodiment which is the best mode for carrying out the present invention, and FIG. 2 is a schematic view of the bilge keel according to the first embodiment as viewed from the stern. 2A is an outline of the bilge keel attachment angle at the center of the ship as seen from the stern, and FIG. 2B is an outline of the stern side attachment angle as seen from the stern. is there. 1 and 2, reference numeral 100 is the same ship as shown in FIG. 8, and reference numeral 1 is a bilge keel provided on the ship side of the ship 100.

  That is, as shown in FIGS. 1 and 2, the bilge keel 1 according to the first embodiment has a total length of 20 to 30% Lpp from the center of the ship 100 in the ship length direction (shown as point M in the figure). The continuous bilge keel 1 is arranged at the lower part on both ship sides of the ship 100. And the bilge keel 1 which concerns on the present Example 1 changes the direction of the bilge vortex which generate | occur | produces in a rear part by adjusting the attachment angle to the hull of the rear part of a bilge keel, and improves propeller propulsion efficiency. Specifically, the water flow behind the bilge keel 1 is inclined so that the rear side is upward from about 20% of the stern of the bilge keel 1 when viewed from the ship side so that the water flow behind the bilge keel 1 flows into the upper end of the propeller 102. .

  As shown in FIG. 2, with respect to the mounting angle of the bilge keel 1 to the hull as viewed from the stern, the bilge keel 105 from the ship side skin 104 to the bottom skin 106 of the ship 100 is located at the center in the ship's direction. In the rearward direction from the stern at about 20% from the stern, it is attached to the curved portion so as to have an obtuse angle with an inclination of about 110 degrees, that is, downward.

  Further, in Example 1, from the rear of about 20% from the stern, the water tank experiment was repeated with the mounting angle of the bilge keel 1 with respect to the curved portion being 110 degrees, and the following data was obtained. . Fig. 3 shows that the bilge keel with a length equivalent to a ship model with a length of 2 meters was installed in the aquarium, and the experiment was attempted by changing the mounting angle at the rear from 20% to 110 degrees from the stern. This data shows the effect. The vertical axis represents horsepower (kW) and the horizontal axis represents speed (knots). Further, in FIG. 3, the solid line indicates experimental data of a bilge keel that is directly caught by the curved portion without changing the angle, and the dotted line indicates the stern of about 20 stern according to the first embodiment. It shows the horsepower reduction effect of the bilge keel 1 attached at an angle of about 100 degrees with respect to the curved portion behind the% portion. As is clear from FIG. 3, in the bilge keel 1 according to Example 1, a reduction effect of 1.0 to 2.0% was observed in the normal output.

Next, the split type bilge keel according to the second embodiment which is the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 4 is a side view of a split type bilge keel according to a second embodiment which is the best mode for carrying out the present invention, and FIG. 5 is a schematic enlarged view showing an outline of each divided bilge keel. FIG. 6 is a diagram showing an outline of the split bilge keel according to the second embodiment as viewed from the stern, and FIG. FIG. 6B is a diagram showing an outline of the stern side bilge keel mounting angle as seen from the stern. 4 to 6, reference numerals 11 to 15 are bilge keels provided separately on the ship side of the ship 100, and are divided types according to the second embodiment in order of 11, 12, 13... From the bow. In the bilge keel, there are provided bilge keels 11, 12, 13, 14, 15 which are divided into a total of five from the first bilge keel 11 on the bow side to the last bilge keel 15.

  That is, as shown in FIGS. 4 to 6, these divided bilge keels 11, 12, 13, 14, and 15 have a total length of 20 to 30 from the center in the length direction of the ship 100 (shown as point M in the figure). Each bilge keel 11, 12, 13, 14, 15 divided by a length of% Lpp is divided and attached to each block.

Of the split-type bilge keels 11, 12, 13, 14, 15, the stern end of the stern split bilge keel 15 as viewed from the ship side so that the rear stream of water flows to the upper end of the propeller. Tilt so that the part is facing upward.
Further, among the split-type bilge keels 11, 12, 13, 14, 15, the angle at which each of the split-type bilge keels is attached to the hull is at the center in the ship length direction (indicated by the symbol “M”) when viewed from the stern direction. The mounting angle of the bilge keel 13 is set to be perpendicular to the curved part from the ship side to the bottom of the ship 100, and the split bilge keel 15 located at the tail is about 100 degrees with respect to the curved part. Install so that the obtuse angle is.

  As shown in FIG. 5, each of the divided bilge keels 11, 12, 13, 14, and 15 has a substantially trapezoidal shape, and the length in the length direction is about 6 m to about 15 m, depending on the block division, and the height. Is about 0.4 m to about 0.6 m, and the angle on the hull side is about 15 degrees. Here, in the work process of constructing the hull for each block, it is better to construct each bilge keel 11, 12, 13, 14, 15 for each block. For each block, each bilge keel is attached to a curved portion from the ship side to the ship bottom. Therefore, the interval between the bilge keels may be an interval that does not disturb the water flow, but an appropriate interval may be determined in consideration of workability in building each block.

  That is, in the split type bilge keel 11, 12, 13, 14, 15 according to the second embodiment, the direction of the bilge vortex is adjusted by adjusting upward the mounting angle of the last bilge keel of the divided bilge keel or the subsequent bilge keel. To improve propeller propulsion efficiency.

  Next, with respect to the split type bilge keel according to the second embodiment, as described above, a water tank experiment of the horsepower reduction effect when variously changing the attachment angle of the bilge keel about 20% from the stern to the curved portion is performed. Repeated. In the tank experiment, a bilge keel equivalent to a ship model with a length of 2 meters was installed in the tank, and correlation data of horsepower with respect to speed was obtained for three types of attachment angles of the last bilge keel 15 of 70 degrees, 90 degrees, and 110 degrees. I tried.

  FIG. 7 shows that the five bilge keels 11, 12, 13, 14, and 15 are attached to a ship model with a length of 2 meters in the aquarium, and the attachment angle of the last bilge keel 15 is changed to the above three types of attachment angles. It is data of the horsepower reduction effect obtained by experimenting. The vertical axis represents horsepower (kW) and the horizontal axis represents speed (knots). In addition, in FIG. 7, the solid line indicates the data of the split type bilge keel when the angle is not changed (when the rear part of the stern of the bilge keel is not tilted about 20% as viewed from the ship side direction). In the case of the attachment angle of 110 degrees, the case indicated by the wavy line indicates the case of the attachment angle of 90 degrees, and the case indicated by the alternate long and short dash line indicates the case of the attachment angle of 70 degrees.

  In either case, it can be seen that the one attached with an angle has the effect of reducing the horsepower, but among these experiments, when the attachment angle of the last bilge keel 15 is set to 110 degrees, the horsepower reduction effect is most effective. I know I can work. In other words, compared with the case where the angle is not changed, the improvement in horsepower reduction of 0.7 to 1.7% is seen in the case of the attachment angle of 70 degrees, and in the case of the attachment angle of 90 degrees, the angle An improvement in horsepower reduction of 1.0 to 2.0% is seen compared to the case where there is no change. Furthermore, in the case of a mounting angle of 110 degrees, it is 1.2 compared to the case where the angle is not changed. It can be seen that there is an improvement in horsepower reduction of ~ 2.2%.

In the second embodiment, the rearmost split bilge keel 15 is tilted so that the stern end of the rearmost split bilge keel is upward when viewed from the ship side so that the rear water flow flows to the upper end of the propeller. but this is not limited to the end of the split Birujiki inclination Le, following the example of the first embodiment described above, among the bilge keel 12, 13, 14, 15 as a whole, from the tail end Regarding the bilge keel behind the bilge keel located at the approximately 20% portion, it may be inclined so that the mounting angle is upward.

  The present invention is used for a ship bilge keel.

FIG. 1 is a side view of a bilge keel (continuous) according to Example 1 which is the best mode for carrying out the present invention; FIG. 2 (A) shows an outline of the mounting angle of the bilge keel in the center of the ship, and FIG. 2 (B) shows an outline of the mounting angle on the stern side, FIG. 3 is a view showing a horsepower reduction effect obtained by attaching a bilge keel corresponding to a ship model with a length of 2 meters in the aquarium, and changing the attachment angle at a 20% portion from the stern in various ways, and performing experiments. FIG. 4 is a side view of a split bilge keel according to a second embodiment which is the best mode for carrying out the present invention; FIG. 5 is a schematic enlarged view showing an outline of each divided bilge keel; FIG. 6 (A) shows an outline of the mounting angle of the bilge keel in the center of the ship, and FIG. 6 (B) shows an outline of the mounting angle of the stern side bilge keel. FIG. 7 shows that the five bilge keels 11, 12, 13, 14, and 15 are attached to a ship model with a length of 2 meters in the aquarium, and the attachment angle of the last bilge keel 15 is changed to the above three types of attachment angles. The figure showing the horsepower reduction effect obtained by experimenting with FIG. 8 is a side view of a hull showing an outline of a conventional general bilge keel. FIG. 9 is a diagram showing an outline of a conventional retractable bilge keel device disclosed in Japanese Utility Model Laid-Open No. 61-138792.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Continuous type bilge keel 11, 12, 13, 14, 15 Split type bilge keel 100 Vessel 102 Propeller 103 Shaft 104 Ship side skin 105 Bilge skin 106 Ship bottom skin

Claims (3)

A bilge keel constructed separately arranged for each block of the ship, both bilge central portion of the ship to the length of 20 to 30% Lpp forward and backward bilge keel of each substantially trapezoidal shape from the central portion of the ship in spaced and arranged for each block, and becomes upward rearward as viewed from ship's side direction the mounting angle to the hull of the stern from 20% position after part of the bilge keel 20% position from the bilge keel or stern uppermost stern The bilge keel is characterized by being inclined like this. Among the divided bilge keels , the mounting angle of the most stern bilge keel or the bilge keel located 20% from the stern in front of the hull is perpendicular to the curved portion from the ship side to the bottom of the ship. In addition , the mounting angle of the stern bilge keel or the bilge keel located at a position 20% from the stern to the hull is inclined upward with respect to the curved portion so that the mounting angle on the bottom side becomes an obtuse angle. The bilge keel according to claim 1. Among the divided bilge keels, the water flow behind the bilge keel indicates the angle of attachment to the hull of the stern of the stern bilge keel or the stern of the bilge keel located 20% from the stern as viewed from the ship side. The bilge keel according to claim 1, wherein the bilge keel has an angle of flowing into the portion.

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