JP2006264649A - Vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vessel capable of reducing resistance generated on the vessel by air pressure at navigation. <P>SOLUTION: The vessel has a hull 1B and a side surface shape of the hull is a shape that a position of an area center A2 of a side surface can be set such that the air pressure received by the side surface of the hull becomes larger at the stern R side from a center of length of hull than the bow F side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a ship such as a dedicated car, a cargo ship such as a container ship, and a passenger ship.

  As shown in FIG. 15, the resistance received by the ship 1 that travels with the propulsive force P can be divided into an underwater resistance R1 and a wind pressure resistance R2. The underwater resistance R1 accounts for most of the total resistance. For this reason, underwater resistance has been studied from the past, and the analysis results are reflected in the current ship shape. However, the wind pressure resistance R2 tends to be neglected, and the actual situation is that the shape has not been improved to reduce the wind pressure resistance R2.

  However, when the ship 1, especially a car-only ship, a container ship, and a passenger ship having a surface shape that easily receives wind pressure, receive wind from diagonally forward, not only the ship speed decreases due to the direct influence of the wind, Underwater resistance may increase due to changes in the attitude of the hull caused by wind (sloped), which may affect operational performance.

  For example, as shown in FIG. 16, when the ship 1 receives the wind W from the diagonally left front with respect to the course F, a yaw moment M that gives a clockwise rotational force is generated in the hull 1. The force of the wind W is decomposed into an X component in a direction opposite to the course F and a Y component in a direction orthogonal to the ship side of the hull 1. In this case, it is necessary for the hull 1 to take the hitting rudder 4 in order to keep the heading in the direction of the course F against the yaw moment M. Further, the hull 1 receives the thrust in the X direction of the hull 1 itself, the X direction force and the Y direction force caused by the wind W, and proceeds obliquely in the V direction.

  The underwater resistance acting on the hull 1 is increased by such a skew. At this time, as the tilt angle β increases, the angle of the hitting rudder 4 also increases, and the resistance that the hull 1 receives from water also increases. As a result, the fuel used increases and the operating cost increases.

  The present invention seeks to provide a ship capable of reducing the amount of fuel used by reducing the tilt angle and reducing the resistance acting on the hull.

This invention has a hull, and the side shape of the hull is
The ship is characterized in that the position of the center of the area of the side surface can be set so that the wind pressure received by the side surface of the hull is greater at the stern side than at the bow side from the center of the captain.

  2. The ship according to claim 1, wherein the center of the area is at least 1% behind the captain in the stern direction from the center of the captain.

  It is preferable to provide a step in the center of the captain of the hull so that the height of the side surface on the stern side is higher than the height on the bow side.

  The upper surface and the lower surface of the stepped portion are preferably connected by a straight line or a curve.

  The side shape of the hull is preferably the shape above the water line.

  According to this invention, since the center of the area of the side surface shape of the hull is set to the stern side with respect to the center of the hull, the hull shape has a small yaw moment when the hull receives wind pressure. For this reason, since the steering angle for navigating the hull in a predetermined direction can be reduced, the underwater resistance can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 to FIG. 4 each show a dedicated car ship having different side shapes. FIG. 1 shows a general car carrier, and the side surface shape of the hull 1A of this car carrier is a first case (original case). FIGS. 2 and 3 are side views of a car carrier suitable for the present invention. The side shape of the hull 1B of the car carrier shown in FIG. 2 is the second case, and the side of the hull 1C of the car carrier shown in FIG. The shape is the third case.

  FIG. 4 shows a hull 1D of a car-only vessel having a side shape different from that of the car-only vessel of the present invention shown in FIGS. 2 and 3, and the side shape of the hull 1D is a fourth case.

  The vertical length L of the hulls 1A to 1D of the first to fourth cases is 190 m (meters), and the height H1 from the bottom of the empty ship to the waterline W is 8.55 m. Here, the inter-vertical length L represents the length of the ship measured by the horizontal distance from the bow tip position (vertical line) intersecting the maximum draft line to the rudder axle center position.

  The height H2 of the portion of the first case hull 1A shown in FIG. 1 excluding the bow F side and the stern R side is 30.86 m, and the height H3 of the bow F portion and the stern R portion is 27.86 m, respectively. It is. The area center A1 of the side shape of the hull 1A determined under the above conditions is the center of the captain L.

  The side surface shapes of the hulls 1B and 1C of the second case and the third case of the present invention shown in FIGS. 2 and 3 are formed with step portions 11 and 12, respectively, in the center of the captain. The height of the step portion 11 of the hull 1B of the second case is set to about 16 m, and the height of the step portion 12 of the hull 1C of the third case is set to about 8 m. Accordingly, the hulls 1B and 1C of the second and third cases have side shapes in which the stern R side is higher than the bow F side from the center of the captain. That is, the side shape on the stern R side from the center C of the captain L is larger than the side shape on the bow F side.

  As for the side shape of the hull 1B of the second case, the height H4 on the bow F side is set to 22.69 m, and the height H5 on the stern R side is set to 38.86 m. The area center A2 of the side surface shape of the hull 1B of the second case determined under the above conditions is a position 13 m closer to the stern R side from the center C of the captain L.

  The side shape of the hull 1C of the third case is set such that the height H6 on the bow F side is 26.46 m and the height H7 on the stern R side is 34.36 m. The area center A3 of the side shape of the hull 1C of the third case determined under the above conditions is a position that is 6.174 m closer to the stern R side from the center C of the captain L.

  The side surface shape of the hull 1D of the fourth case shown in FIG. 4 is similar to the second and third cases. A step portion 13 having a height of about 8 m is formed in the center of the ship length L. 13, the height H8 on the bow F side is formed higher than the height H9 on the stern R side. The height H8 on the bow F side is set to 34.36 m, and the height H9 on the stern R side is set to 26.46 m. The area center A4 of the side surface shape of the hull 1D of the fourth case determined under the above conditions is a position closer to the bow F side of 7.428 m from the center C of the captain L.

  That is, the side shape of the hull 1D of the fourth case is opposite to the height of the bow F side and the stern R side compared to the side shapes of the hulls 1B and 1C shown in the second and third cases. The position of the area center A4 is 7.428 m closer to the bow F side from the center C of the captain L.

  The step portions 11 and 12 formed on the hulls 1B and 1C of the second case and the third case connect the upper surface and the lower surface of the step with a straight line (plane), but are not a straight line but a curved line (curved surface). It may be connected. In this case, if the curved surface is raised from the lower surface to a concave curved surface and connected to the upper surface by a convex curved surface, the wind pressure resistance received by the step portions 11 and 12 can be reduced. Moreover, you may connect the upper surface and lower surface of level | step differences 11 and 12 with a slope.

Next, theoretical calculation of wind pressure characteristics and various characteristics at the time of sailing of the respective hulls 1A to 1D having the side shapes of the first to fourth cases will be described.
FIG. 5 shows the relationship between the wind direction received by the hulls 1A and 1B of the first and second cases and the X direction wind pressure coefficient, FIG. 6 shows the relationship between the wind direction and the Y direction wind pressure coefficient, and FIG. The relationship with the wind pressure moment coefficient (yaw moment) is shown. In addition, the wind direction 0 degree | times shown on a horizontal axis is a head wind, 90 degree | times is a cross wind, and 180 degree | times is a tail wind.

  In the case of the hulls 1A and 1B of the first case and the second case, as can be seen from FIG. 5 and FIG. 6, there is almost no difference between the wind pressure coefficient in the X direction and the wind pressure coefficient in the Y direction. As can be seen from FIG. 7, the wind pressure moment coefficient is smaller in the hull 1B of the second case than in the hull 1A of the first case. That is, the wind pressure moment coefficient around the Z-axis is such that the area center A1 is located at the center C of the ship length L in the second case hull 1B in which the area center A2 is located on the stern R side with respect to the center C of the ship length L. It turns out that it is smaller than the case of the hull 1A of the first case.

  FIG. 8 shows the rate of decrease in ship speed, the lateral flow angle and the steering angle (the steering angle) when the wind direction with respect to the hulls 1A and 1B of the first case and the second case is changed in the range of 0 to 180 degrees. ). In the same figure, the boat speed reduction rate of the first case is indicated by a curve of V1, the lateral flow angle is β1, and the steering angle is δ1, the boat speed reduction rate of the second case is V2, the lateral flow angle is β2, and the steering angle is It is shown by the curve of δ2. The calculation conditions are an initial ship speed of 20 knots, a propeller rotational speed of 94.7 times / minute, and an absolute wind speed of 15 m / sec.

  For example, when the ship speed reduction rate V1 and V2 when the wind direction is 45 degrees are compared, the ship speed reduction rate V1 in the case 1A of the first case hull is 15%, whereas the ship in the second case. The rapid decrease rate V2 is 11%.

  In the case of a lateral flow angle, the hull 1B (β2) of the second case is smaller than the case (β1) of the first case, and the hull 1B (δ2) of the second case is also a steering angle. In the first case, it is smaller than (δ).

  In other words, the first case side surface hull 1A whose area center A1 is in the center C of the hull 1 and the side surface area center A2 which is located closer to the stern R side than the first case hull 1A. When compared with the hull 1B of the second case, the rate of decrease in ship speed is lower in the second case in the wind direction range of 15 to 135 degrees, and the lateral flow angle and rudder angle are the most in the range of wind direction 0 to 180 degrees. Case 2 is smaller. That is, such a result is obtained because the yaw moment M generated when receiving the wind is smaller in the hull 1B of the second case than in the hull 1A of the first case.

  FIG. 9 shows the horsepower increase rate when the wind direction with respect to the hulls 1A and 1B in the first case and the second case is changed in the range of 0 to 180 degrees. That is, FIG. 9 shows the rate of increase of the horsepower required to keep the boat speed constant with respect to changes in the wind direction from the required horsepower at the same boat speed when there is no wind, and the curve P1 in the figure is the first This is the case, and the curve P2 is the second case. As is apparent from the figure, the rate of increase in horsepower is lower in the range of the wind direction of 20 to 135 degrees in the side hull 1B of the second case than in the side hull 1A of the first case. You can see that

  FIG. 10 shows the relationship between the ship speed reduction rate, the lateral flow angle, and the rudder angle when the wind direction is changed in the range of 0 to 180 degrees with respect to the hulls 1A and 1C of the first case and the third case. . In the figure, the boat speed reduction rate of the first case is indicated by a curve of V1, the lateral flow angle is β1, and the steering angle is δ1, the boat speed reduction rate of the third case is V3, the lateral flow angle is β3, and the steering angle is δ3. Shown as a curve. The calculation conditions are an initial ship speed of 20 knots, a propeller rotational speed of 94.7 times / minute, and an absolute wind speed of 15 m / sec.

  When the hulls 1A and 1C of the first case and the third case are compared, the hull 1C of the third case is the same as the hulls 1A and 1B of the first case and the second case. The rate of decrease in ship speed generated when receiving wind from the hull 1A of the case is low in most wind direction ranges, and the lateral flow angle and rudder angle are also small in most wind direction ranges. That is, since the yaw moment M generated when the wind is received is smaller in the third case hull 1C than in the first case hull 1A, such a result is obtained.

  FIG. 11 shows the horsepower increase rate when the wind direction with respect to the hulls 1A and 1C in the first case and the third case is changed in the range of 0 to 180 degrees. That is, FIG. 11 shows the rate of increase in horsepower required to keep the boat speed constant with respect to changes in the wind direction. In the figure, the curve P1 is the first case, and the curve P3 is the third case. is there. As is apparent from the figure, the rate of increase in horsepower is lower in the range of the wind direction of 20 to 135 degrees in the side case 1C of the third case than in the case 1A of the side shape of the first case. You can see that

  On the other hand, from the comparison between the hull 1A of the first case and the hull 1B of the second case and the comparison of the hull 1A of the first case and the hull 1C of the third case, the area of the hull 1C of the third case. In order to keep the ship speed constant by reducing the lateral flow angle and the rudder angle as well as reducing the ship speed reduction rate of the hull 1B of the second case where the area center A2 is located on the stern R side than the center A3. It can be seen that the required increase in horsepower is small.

  FIG. 12 shows the relationship between the ship speed reduction rate, the lateral flow angle, and the rudder angle when the wind direction is changed in the range of 0 to 180 degrees with respect to the hulls 1A and 1D of the first case and the fourth case. . In the figure, the boat speed reduction rate of the first case is indicated by a curve of V1, the lateral flow angle is β1, and the steering angle is δ1, the boat speed reduction rate of the fourth case is V4, the lateral flow angle is β4, and the steering angle is δ4. Shown as a curve. The calculation conditions are an initial ship speed of 20 knots, a propeller rotational speed of 94.7 times / minute, and an absolute wind speed of 15 m / sec.

  When the hulls 1A and 1D of the first case and the fourth case are compared, the hull speed reduction rate that occurs when the hull 1D of the fourth case receives wind rather than the hull 1A of the first case is almost the same. The side flow angle and rudder angle are also large in most wind direction ranges. That is, since the yaw moment M generated when receiving the wind is larger in the fourth case hull 1D than in the first case hull 1A, such a result is obtained.

  FIG. 13 shows the horsepower increase rate when the wind direction with respect to the hulls 1A and 1D of the first case and the fourth case is changed in the range of 0 to 180 degrees. That is, FIG. 13 shows the rate of increase in horsepower required to keep the boat speed constant with respect to changes in the wind direction. In the figure, the curve P1 is the first case, and the curve P4 is the fourth case. is there. As is apparent from the figure, the rate of increase in horsepower is larger in the range of the wind direction of 20 to 135 degrees in the side hull 1D of the fourth case than in the side hull 1A of the first case. I understand.

  From the results shown in FIGS. 12 and 13, when the area center A4 is on the bow F side of the center C of the hull 1D as in the fourth case, the area center A1 is the center of the hull 1A as in the first case. Compared to the case of C, it can be seen that it is a disadvantageous condition for operation in terms of the ship speed reduction rate, the lateral flow angle, the rudder angle and the horsepower change rate.

  FIG. 14 shows the increase in horsepower when the hulls 1A to 1D of the first to fourth cases receive a wind of 15 m / sec in each wind direction, and the ship speed (knots) is obtained from the result of averaging them in all wind directions. The relationship between horsepower (kw) is obtained. In the figure, the curve Z1 is the first case, the curve Z2 is the second case, the curve Z3 is the third case, and the curve Z4 is the fourth case. Note that the curve Z0 in the figure shows a case where the wind pressure is not received. In this case, no difference occurs because the shape below the surface of the water is the same in any of the first to fourth cases.

  For example, comparing the rate of increase in horsepower required to maintain a ship speed of 18.8 knots from the same figure in the first case, the second case, and the third and fourth cases, The case is P1, the second case is P2, the third case is P3, the fourth case is P4, and the relationship between these sizes is P4> P1> P3> P2.

  That is, the horsepower can be minimized by positioning the area center A2 closer to the stern R side than the center C of the captain L like the hull 1B of the second case, and the third case, then the center of the hull 1A. A first case in which the area center A1 is positioned at C and a fourth case in which the area center A4 is positioned on the stern R side from the center C are arranged in this order.

  Even from this, it can be seen that the hulls 1B and 1C whose area center is located on the stern R side than the center C of the captain L are less resistant to the wind pressure received during operation.

  It was calculated by calculation that a horsepower reduction effect of about 1% can be obtained by setting the position of the center of the side surface of the hull to a position 1% behind the captain in the stern direction from the center of the captain. Therefore, since it is practically effective if a horsepower reduction effect of 1% or more is obtained as compared with the conventional ship, the center of the area may be 1% or more behind the center of the captain, for example, 2%, 3% or More than that, the point is that the more the center of the area is behind the center of the captain, the more the horsepower reduction effect can be increased.

The side view which shows the hull of a 1st case. The side view which shows a 2nd case hull. The side view which shows the hull of a 3rd case. The side view which shows the hull of a 4th case. The figure which shows the relationship between a wind direction and the influence coefficient of a X direction. The figure which shows the relationship between a wind direction and the influence coefficient of a Y direction. Diagram showing the relationship between wind direction and wind pressure moment coefficient around the Z axis The figure which shows the relationship between the wind direction of the hull of a 1st case, and the hull of a 2nd case, a ship speed fall rate, a lateral flow angle, and a steering angle. The figure which shows the relationship between the wind direction of the hull of a 1st case, and the hull of a 2nd case, and a horsepower increase rate. The figure which shows the relationship between the wind direction of the hull of a 1st case, and the hull of a 3rd case, a ship speed fall rate, a lateral flow angle, and a steering angle. The figure which shows the relationship between the wind direction of the hull of a 1st case, and the hull of a 3rd case, and a horsepower increase rate. The figure which shows the relationship between the wind direction of the hull of a 1st case, and the hull of a 4th case, a ship speed fall rate, a lateral flow angle, and a steering angle. The figure which shows the relationship between the wind direction of the hull of a 1st case, and the hull of a 4th case, and a horsepower increase rate. The figure which shows the relationship between the speed of the hull of the 1st thru | or 4th case, and the horsepower for maintaining the speed. The figure for demonstrating the resistance which acts on a hull. The figure for demonstrating the resistance force which generate | occur | produces in a hull.

Explanation of symbols

  1A to 1D ... hull, F ... bow, R ... stern, center of area ... A1-A4.

Claims (5)

It has a hull, and the side shape of this hull is
A ship capable of setting the position of the center of the area of the side face so that the wind pressure received by the side face of the hull is larger from the center of the captain to the stern side than the bow side.   2. The ship according to claim 1, wherein the center of the area is at least 1% behind the captain in the stern direction from the center of the captain.   2. A ship according to claim 1, wherein a step portion is provided in a center portion of the captain of the hull, and a height of a side surface on the stern side is made higher than a height on a bow side.   The ship according to claim 3, wherein the upper surface and the lower surface of the stepped portion are connected by a straight line or a curve.   The ship according to any one of claims 1 to 4, wherein a side shape of the hull is a shape above the water line.

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