JP2007237895A - Marine vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a marine vessel an enlarging degree of a vessel form of which is large, a bow end of which is a vessel form near to a fore perpendicular (F.P.), capable of reducing long-run average water flow medium wave making resistance, restraining wave intermediate resistance increase and restraining sea water driving. <P>SOLUTION: A shape of a lateral cross-section of a flare of a bow part above the maximum draft ZO is formed by having a recessed part 10 constricted to the side of a hull central line C.L. from a vertical line L(x) and height Hm of a center of the recessed part 10 is made height in a range of more than 0.5 time and less than 3.0 times of water head hl calculated by (0.5×Vs×Vs)/g when sea speed of the vessel is specified as Vs and gravitational acceleration is specified as (g) on the upper side of the maximum draft ZO in a region between a position of a bore end Xf and a position of at least 10% of length between perpendiculars Lpp in the rear of the fore perpendicular F.P. concerning the vessel lengthy direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ship capable of improving the propulsion performance in a full load state, and more specifically, to reduce the wave-making resistance generated from the hull portion above the full load water line due to the rise in the water surface at the bow and the increase in resistance in the waves. The present invention relates to a ship having a bow shape.

  In the conventional ship, as shown in FIGS. 6 to 8, the bow flare gradually increases the water line area from directly above the draft line Z0 of the maximum draft (structural draft: Scantling draft) and leads to the upper deck Z3. It spreads like so. This is because the bow requires a storage space for the anchoring device, and the upper deck of the bow requires a certain deck area for mooring work and anchoring work. It is.

  As shown in FIG. 9, the bow flare has a small effect even when the water level rises above the maximum draft Z0 in the vicinity of the stagnation point O of the bow, and the action of water on the portion above the maximum draft Z0 is particularly small. It is based on the design philosophy that there is no need to think about it.

  However, as a result of observing the state of the aquarium experiment and the voyage of the actual ship, the present inventors have taken into consideration the rise in the water level around the stagnation point O of the bow, and this rise in the water level is taken into account. It was found that by adopting the bow shape, it was possible to reduce the wave-making resistance and the wave resistance increase during flat water navigation.

As shown in FIG. 9, during the navigation of the ship, the bow and water have a relative speed Vs, and when viewed in a coordinate system fixed on the ship, Will flow in at a flow velocity Vs. Therefore, in an enlarged ship with a blunt bow, the water flow velocity Vo becomes zero at the stagnation point O on the hull center line (center line: CL) of the bow, so that the density of water is ρ, and the gravitational acceleration When the the g, the relationship between the in hydrocephalus h1 and distant hydrocephalus hs the stagnation point O, the Bernoulli's theorem, ρ × g × ho + ρ × Vo 2/2 = ρ × g × hs + ρ × Vs 2/2 next The water head h1 at the stagnation point O is h1 = Vs ² / (2 × g) −Vo ² / (2 × g) + hs. Here, when Vo = 0 and hs = 0, h1 = Vs ² / (2 × g).

In other words, the water head h1 indicating the amount of water rising at the stagnation point O of the bow is Vs ² / (2 × g), and at the tip of the bow, up to about this water head h1 (Z1 line) when sailing. Will rise. Accordingly, the actual submerged portion is in the vicinity of the position Z1 that is higher than the full draft D0 by the head h1 in the vicinity of the bow. For example, in a ship having a ship speed of 15 kt (knots), Vs = 7.72 m / s, and the head h1 is 3.0 m.

  Therefore, when the bow shape in which the flare immediately spreads from the maximum draft Z0 is adopted as in the conventional hull form shown in FIGS. 6 to 8, the wave generated in the flare part becomes large even during the flat water navigation, and the hull form When the hull is large and the bow end is close to the bow normal (FP), the bow flare has less overhanging than the conventional hull so that the flare inclination angle θ is large. The wave that hit the bow is easy to go up to the deck and seawater is easy to drive. In addition, the wave that collided with the bow is likely to rise upward, so that the vertical movement of the wave at the bow end increases, the forward push (wave reflection) also increases, and the wave reflection is the main component in the waves. The resistance increase also increases.

  In this connection, with respect to the portion above this maximum draft, in all waterline surface shapes, the bow shape is within 0.02 × Lov (the total length of the ship) behind the bow waterline within 50 °, A hypersized ship that sharpens the bow as much forward as possible to alleviate the wave reflection and wave breaking phenomenon at the bow forward and reduce the increase in resistance in waves has been proposed (see, for example, Patent Document 1). .

However, in this bow shape, there is a problem that the wave-making resistance due to the rise of the water surface at the bow portion described above cannot be reduced because the waterline shape changes greatly at the upper and lower sides with respect to the maximum draft line. Further, since the shape of the upper deck is limited, there is a problem that it is difficult to store the anchoring device and to secure a space for anchoring work.
JP 2000-335477 A

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to create a flat water structure with a hull shape in which the hull shape is large and the bow end is close to the bow perpendicular (FP). An object of the present invention is to provide a ship that can reduce wave resistance, suppress an increase in resistance in waves, and suppress seawater driving into an upper deck.

  The ship of the present invention for achieving the above object is a range between the position of the bow end and the position at least 10% of the length between the normals (Lpp) behind the bow perpendicular (FP) with respect to the direction of the captain. The cross-sectional shape of the flare of the bow portion above the maximum draft is formed with a concave portion constricted on the hull center line (CL) side with respect to the vertical line, and the height of the center of the concave portion is increased. This is 0.5 above the head (h1) calculated by (0.5 × Vs × Vs) / g, where Vs is the navigational speed of the ship, and g is the acceleration of gravity. It is comprised so that it may be set as the height within the range of more than twice and less than 3.0 times.

  This maximum draft is the maximum draft that can be navigated by the ship, such as a structural draft (Scantling draft), which is determined by the structural strength in terms of material dimensions, etc. Sailing is to be carried out at a draft that is shallower than the draft draft that is determined at the time of design. In addition, the structural draft is a draft corresponding to the summer full-scale drought calculated by a method defined by the International Full Flooding Convention (ILLC), and the material dimensions are determined by this draft, and hence is called the structural draft. And a ship does not navigate by a draft larger than this structural draft.

  The height (Hm) of the center of the recess means the upper end (Ht) and the lower end (Hb) of the intersection of the vertical line passing through the point where the shape of the hull in the cross section of the hull intersects the maximum waterline (Z0) and the recess. Mean height (Hm = (Ht + Hb) / 2).

  And since the water surface rises in front of the bow part, the effect of reducing the pitching amount and the increase in resistance in waves can be increased by arranging the height of the center of the recess at an appropriate position above the maximum water line. . If the height of the center of the recess is made smaller than 0.5 times the head of water (h1 = (0.5 × Vs × Vs) / g), the water flow will reach the spread of flare due to the rise of the water surface. The resistance reduction effect is reduced. On the other hand, if the height of the center of the recess is made larger than 3.0 times the head of the water, it is difficult for the water flow to reach the flared area even in the waves, and a resistance reduction effect can be expected, but it is difficult to store the anchoring device. And the problem that the bow impact force increases due to the sudden expansion of the flare.

  Moreover, if the height of the center of this recessed part 10 is set within the range of 0.9 times to 2.6 times the head of water, the flare inclination angle remains relatively small when enlarged from this range toward the upper deck. It is more preferable because the spread of the bow flare on the upper deck can be made relatively large, and the anchoring device can be stored and the deck arrangement can be facilitated while maintaining a low bow impact force. It is particularly suitable for ships where the full draft is not far from the maximum draft.

  According to this configuration, in the vicinity of the bow portion, the shape of the conventional hull shape is cut above the maximum draft and a concave portion (constricted portion) is provided, so that water rising at the bow portion and waves incident on the bow portion are The recesses escape to the left and right heel sides and flow smoothly backward. Therefore, in flat water, wave resistance at the bow is reduced and propulsion resistance in flat water is reduced, and in waves, the reflection of incident waves at the bow is reduced and wave resistance is mainly composed of waves. Increase decreases.

  In the above-mentioned ship, the bow flare from the horizontal line at the mold depth position in the cross-sectional shape in the range between the position of the bow end and the position of 2% of the length between the vertical lines behind the bow perpendicular in the ship direction. The tilt angle is configured to be not less than 30 degrees and not more than 50 degrees.

  The range of the bow flare tilt angle between 30 ° and 50 ° is an experimentally obtained value. By setting the bow flare tilt angle to this range, the bow flare has a shape that is open on both sides of the conventional ship shape. The wave that collided with the bow is returned near the deck, and the wave that collides with the bow part is returned near the upper deck (deck), so that it is difficult for the wave to be driven onto the upper deck. When the bow flare inclination angle is smaller than 30 degrees, the effect of suppressing the pitching of the hull is reduced, and the effect of suppressing seawater driving on the upper deck is also reduced. In addition, when the angle is less than 30 degrees, there is a problem that the work at the time of ship construction increases. And if the bow flare inclination angle is larger than 50 degrees, the bow flare part will open too much and it will be hit by waves from below, so it will be necessary to reinforce the strength, and the pitching of the hull will be promoted, so the pitching suppression effect will be Fade.

  In the above-mentioned ship, the width direction position at a position of 1% of the length (Lpp) between the vertical lines behind the bow perpendicular line (FP) in a plan view regarding the shape in which the positions of the center heights of the concave portions are connected. Is within a fan shape that opens from 100 ° to 140 ° on both sides toward the rear from the intersection of the hull center line (CL) and the bow (from 50 ° to 70 ° on each side). Formed as follows.

  According to this configuration, the shape connecting the height positions of the centers of the recesses does not bulge, and the water flow flowing into the recesses easily flows backward, so that the wave reflected in the bow direction Therefore, the propulsion resistance in flat water and the increase in resistance in waves are reduced. On the other hand, when the position in the width direction of the waterline surface is outside the fan shape, the shape of the waterline surface of the bow portion is swollen, and the water flow flowing into the concave portion does not flow smoothly backward and is reflected in the bow direction. Since more waves are generated, it is impossible to suppress an increase in the resistance to propulsion in plain water and an increase in resistance in waves.

  In the above-mentioned ship, the foremost end of the bow is in the range of 0% to 3.0% of the length between the perpendiculars (Lpp) forward of the bow perpendicular (FP), and the square coefficient (Cb) Is 0.80 to 0.90 and the ship has a voyage speed of 0.12 to 0.19 in terms of Froude number (Fn) or a large ship with a vertical length (Lpp) of 150 to 350 m In particular, a great effect can be achieved.

  The fore end of the bow (the bow end) is in the range of 0% to 3.0% of the length Lpp between the fronts in front of the bow perpendicular (FP), and the bow end is relatively perpendicular to the bow perpendicular. In a ship shape close to (FP), seawater can easily be driven with the conventional bow flare shape, so the effect of the present invention is great.

  The square coefficient Cb is Cb = V / (Lpp × B × d), where V is the drainage volume of the ship, Lpp is the vertical length of the ship, B is the mold width, and d is the draft. Since this is a dimension value, and the value of this square coefficient is large, the degree of enlargement is large, so the effect of the present invention is further increased.

The Froude number Fn is a dimensionless display with respect to the ship speed Vs (m / s). When the length between the normals of the ship is Lpp (m) and the gravitational acceleration is g (m / s ² ), Fn = Vs / ( g × Lpp) ^1/2 , which is a dimensionless value. The rise of the water surface in the front part of the bow becomes relatively high, and the propulsion resistance and the increase in resistance in the waves do not become extremely large. The proportion is also relatively large. Note that the nautical speed Vs is sometimes referred to as a planned speed or the like, and therefore the nautical speed is assumed to include the planned speed in this case as well.

  Furthermore, when the ship length (inter-vertical length Lpp) becomes a ship of about 150 m to 350 m, the ship becomes relatively large and the ship speed becomes relatively slow, and the effect of the present invention is enhanced.

  According to the ship of the present invention, the degree of enlargement of the hull form is large and the bow end is close to the bow perpendicular (FP), and the bow perpendicular (FP) from the position of the bow end in the captain direction. In the range between at least 10% of the length between the vertical lines (Lpp) at the rear of the ship, the concavity narrowed on the hull centerline (CL) side is provided at an appropriate height above the maximum draft In addition to reducing wave resistance in plain water, it is possible to suppress an increase in resistance in waves and to suppress seawater intrusion into the upper deck.

Hereinafter, embodiments of a ship according to the present invention will be described with reference to the drawings.
As shown in FIG. 1 to FIG. 3, the ship 1 according to the embodiment of the present invention has a length Lpp of at least 10 from the position Xf of the bow end to the rear of the bow perpendicular (FP) in the ship length direction. % Of the cross-sectional shape Yb (x, z) of the bow flare above the maximum draft Z0 in the range between the position X3 and the vertical axis L. L. It is formed with a concavity 10 constricted on the side.

  As shown in FIG. 1, in the hull cross section (X = x) in which the concave portion 10 is provided, the center height Hm (x) of the concave portion 10 is the maximum in the shape Yb (x, z) of the hull shape in the cross section of the hull. Average height Hm (x) (= (Ht (x) + Hb) between the upper end Ht (x) and the lower end Hb (x) of the intersection of the vertical line L (x) passing through the point P0 intersecting the waterline Z0 and the recess 10 (X)) / 2). And since the water surface rises in front of the bow, the effect of reducing the pitching amount and the increase in resistance in the waves by arranging the height Hm (x) of the center of the recess 10 at an appropriate position above the maximum water line Z0. Can be increased. This center height Hm (x) is calculated as (0.5 × Vs × Vs) / g, where the navigation speed of the ship is Vs and the gravitational acceleration is g. XVs × Vs) / g), and a value within a range of 0.5 to 3.0 times. More preferably, the height Hm (x) of the center of the concave portion 10 is set to a value within a range of 0.9 times to 2.6 times the water head h1.

  If the height Hm of the center of the recess 10 is made smaller than 0.5 times the head of water (h1 = (0.5 × Vs × Vs) / g), the water flow will reach the part where the flare spreads due to the rise of the water surface. Therefore, the resistance reduction effect is reduced. On the other hand, if the height Hm of the center of the concave portion 10 is larger than 3.0 times the head h1, the water flow is difficult to reach the flare spreading portion even in the waves, and the resistance reduction effect can be expected. The problem that storage becomes difficult and the problem that a bow impact force becomes large by spreading a flare rapidly arise.

  Further, when the height Hm of the center of the concave portion 10 is in the range of 0.9 times to 2.6 times the water head h1, when the range is expanded toward the upper deck Z3, the flare inclination angle θ is relatively large. The spread of the bow flare on the upper deck can be made relatively large while remaining small, and it is more preferable because the anchoring device can be stored and the deck arrangement can be facilitated while the bow impact force is kept low. In particular, it is suitable for ships where the full draft dfull is not far from the maximum draft Z0.

  Further, in the hull transverse section (X = x) in which the concave portion 10 is provided, the vertical length of the concave portion (Lz (x) = Ht (x) −), which is the difference between the upper end Ht (x) and the lower end Hb (x) of the concave portion 10. Hb (x)) is preferably 0.5 times or more and 3.0 times or less of the water head h1. If the vertical length Lz (x) of the recess is smaller than 0.5 times the head h1, the water flow cannot be smoothly flown to both sides, and if it is larger than 3.0 times the head h1, the flare is widened. And it becomes difficult to store the anchoring device. Also, if the flare is expanded suddenly, the bow impact force increases.

  Further, in the hull transverse section (X = x) where the recess 10 is provided, the depth of the recess 10 is set to the center line C.V. L. The distance Ly (x) between the innermost position Pb (x) and the vertical line L (x) passing through the point P0 (x) where the shape Yb (x, z) of the hull intersects the maximum waterline Z0 The depth Ly (x) of the recess 10 is preferably 5% or more and 15% or less of the mold width B. If the depth Ly (x) of the recess is smaller than 5% of the mold width B, the water flow cannot smoothly flow to both sides, and if it is larger than 15% of the mold width B, the flare can be widened. This makes it difficult to store the anchoring device. Also, if the flare is expanded suddenly, the bow impact force increases.

  According to this configuration, in the vicinity of the bow portion, the shape of the conventional hull shape is cut away from the maximum draft Z0 and the concave portion (constricted portion) 10 is provided, so that water rising at the bow portion and waves incident on the bow portion are generated. The recess 10 escapes to the left and right heel sides and smoothly flows backward. Therefore, in flat water, wave resistance at the bow decreases and propulsion resistance in flat water decreases. In addition, since the reflection of the incident wave forward (pushing the wave forward) is suppressed during the wave, the increase in resistance in the wave, which is mainly composed of the reflection of the wave, is reduced. In addition, by providing the concave portion 10, the relative vertical fluctuation amount of the wave with respect to the bow end is reduced, so that it is difficult for the wave to be driven onto the upper deck (Deck) Z <b> 3.

  In addition, the bow flare inclination angle at the position of the mold depth D in the range between the position of the bow end Xf and the position Xr of 2% of the length (Lpp) between the perpendiculars behind the bow perpendicular (FP). θ (x) is configured to be 30 ° to 50 °.

  The bow flare inclination angle θ (x) is an angle from the horizon. Further, by setting the bow flare inclination angle θ (x) in the range of 30 ° to 50 ° obtained experimentally, the bow flare has a shape that is open on both sides of the conventional hull form. Therefore, the wave that collided with the bow is returned near the deck, and the wave that collides with the bow part is returned near the upper deck (deck), so that it is difficult for the wave to be driven onto the upper deck. When the bow flare inclination angle θ (x) is smaller than 30 degrees, the effect of suppressing the pitching of the hull is reduced, and the effect of suppressing seawater driving into the upper deck is also reduced. In addition, when the angle is less than 30 degrees, there is a problem that the work at the time of ship construction increases. If the bow flare inclination angle θ (x) is greater than 50 degrees, the bow flare portion will open too much and will be hit by waves from below, so that it will be necessary to reinforce the strength or the pitching of the hull will be promoted. The effect of suppressing pitching is reduced.

  Further, as shown in FIG. 3, the length between the vertical lines behind the bow perpendicular (FP) in a plan view with respect to the shape in which the positions of the center heights (Z = Hm (x)) of the recesses 10 are connected. The width direction position Ybp (X = 0.01 × Lpp, Z = Hm (X = 0.01 × Lpp)) at the position Xp of 1% of (Lpp) is the hull center line C.I. L. Are formed so as to be accommodated in a fan shape (shaded portion in FIG. 3) that opens 100 ° to 140 ° on both sides (50 ° to 70 ° each on one side) from the intersection Pf with the bow. Alternatively, in a plan view, the hull center line C.I. L. Is formed so that the inclination angle β is within 60 degrees.

  According to this configuration, the shape of the water line at the height Hm at the center of the concave portion 10 is not rounded, the water flow flowing into the concave portion 10 can easily flow smoothly backward, and waves reflected in the bow direction are generated. Therefore, the resistance to propulsion in flat water and the increase in resistance in waves are reduced. On the other hand, when the position Ybp in the width direction of the water line surface is outside the fan shape, the water line surface shape of the bow portion is rounded, and the water flow flowing into the recess 10 does not flow smoothly backward, and in the bow direction. Since the number of reflected waves increases, it becomes impossible to suppress an increase in resistance to propulsion in flat water and an increase in resistance in waves.

  Further, in the above-mentioned ship, the foremost end of the bow is in the range of 0% to 3.0% of the length Lpp between the perpendiculars ahead of the bow perpendicular (FP), and the square coefficient Cb is 0.80. This is particularly effective in the case of a ship having a voyage speed Vs of 0.12 to 0.19 in terms of Froude number Fn or a large ship having a perpendicular length (Lpp) of 150 m to 350 m.

  As an example, in a bulk carrier hull with a square coefficient (Cb) of 0.85, as shown in FIG. 4, hulls As, Bs, Cs, deformed between a maximum draft Z0 and a predetermined set height h1. For each Ds, a model ship with a captain Lpp of 3.42 m was prepared.

  FIG. 5 shows the total resistance coefficient in the wave resistance test in the water tank. In Example Cs, the wave resistance is also smaller than those in Comparative Example As and Examples Bs and Ds. Further, among the examples Bs, Cs, and Ds, the resistance of the example Cs in which the recess is between the examples Bs and Ds is small, and the effect of the present invention is achieved by making the shape of the recess appropriate. Has been found to be more effective.

It is a partial front view which shows the shape of the bow part of the ship of embodiment which concerns on this invention. It is a partial side view which shows the shape of the bow part of the ship of FIG. It is a fragmentary top view which shows the shape of the bow part of the ship of FIG. It is a partial front view which shows the shape of the bow part of the ship of an Example and a comparative example. It is a figure which shows the comparison of the plain water resistance test result of an Example and a comparative example. It is a partial front view which shows the shape of the bow part of the ship of a prior art. It is a partial side view which shows the shape of the bow part of the ship of FIG. It is a fragmentary top view which shows the shape of the bow part of the ship of FIG. It is a figure for demonstrating the water surface rise in a bow part.

Explanation of symbols

1,1X Ship 10 Concave part (constriction part)
As Comparative Example Bs, Cs, Ds Example B Mold Width C.I. L. Hull Chuo Line (Center Line)
D type depth P. Bow vertical line Fn Froude number g Gravity acceleration h1 Water head at the stagnation point hs Water head far away from the bow Hb (x) Lower end of intersection of vertical line and recess Hm (x) Center height of recess Ht (x ) Upper end of intersection of vertical line and recess Lh (x) Vertical length of recess Ly (x) Depth of recess L (x) Vertical line O Stagnation point
P0 (x) Point where the shape of the hull shape in the cross section of the hull intersects the maximum waterline Pb (x) Point of the innermost position of the recess Pf Intersection of the shape connecting the height of the center of the recess and the hull centerline Vs Velocity Velocity Vo Stagnation velocity Xf Bow end position Xr 0.02 × Lpp position Xp 0.01 × Lpp position X3 0.1 × Lpp position Yb (x, z) Hull shape (crossing flare) Surface shape)
Ybp Width direction position in Xp of the shape of connecting the height position of the center of the recess Z0 Maximum draft (structural draft)
Z3 Upper deck θ (x) Bow flare tilt angle α Fan-shaped angle
β tilt angle

Claims (4)

  With respect to the direction of the ship's head, the shape of the cross-section of the flare of the bow part above the maximum draft is higher than the vertical line in the range between the position of the bow end and at least 10% of the length between the perpendiculars behind the bow perpendicular. When the center of the recess is formed with a concavity constricted on the hull centerline side, the height of the center of the recess is above the maximum draft, the navigation speed of the ship is Vs, and the gravitational acceleration is g. 0.5 × Vs × Vs) / g, a ship having a height within a range of 0.5 to 3.0 times the head of water.   In the direction of the ship's direction, the bow flare inclination angle from the horizontal line at the mold depth position is 30 degrees in the cross-sectional shape in the range between the position of the bow end and the position of 2% of the length between the perpendiculars behind the bow perpendicular. The ship according to claim 1, wherein the ship is at least 50 degrees.   With respect to the shape in which the positions of the center heights of the recesses are connected, in a plan view, the position in the width direction at a position of 1% of the length between the vertical lines behind the bow vertical line is rearward from the intersection of the hull center line and the bow part. The ship according to claim 1 or 2, wherein the ship is formed so as to be within a fan shape opened at 100 degrees to 140 degrees on both sides.   The foremost end of the bow is in the range of 0% to 3.0% of the length between the vertical lines ahead of the bow vertical line, the square factor is 0.80 to 0.90, and the navigation speed is 0. 0 in terms of fluid number. The ship according to any one of claims 1 to 3, wherein the ship is 12 to 0.19.

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