KR20120028366A - Biaxial stern catamaran ship - Google Patents

Abstract

The propulsion performance of the ship is improved by effectively utilizing the flow generated behind the skeg during the propulsion of the ship. In a two-axis stern twin vessel (1) having two propellers, propulsion means (210,220) for driving the two propellers to propel the two-axis twin vessel, and the hull of the two-axis stern twin vessel Two skegs (11, 12) provided in each of the two, and the center of the drive shaft of the two propellers are positioned with an offset from the center axis of the two skegs respectively. The skeg has an S-shaped twisted shape that rotates the flow naturally occurring toward the rear of the skeg at the time of the ship's navigation, and the propeller whose optimum rotational position is positioned at the optimum position is a wing surface as a counter flow. Capture a lot from a blade surface.

Description

Biaxial Stern Catamaran Vessel {BIAXIAL STERN CATAMARAN SHIP}

The present invention relates to a biaxial stern catamaran ship having two skegs and two propellers.

In recent years, in the field of ships, various methods for realizing energy saving have been studied due to the increase in fuel cost, energy and environmental problems. As a method of energy saving of the ship itself except the infrastructure such as a ship operation method and a port, there is an increase in the efficiency of the engine or a linear improvement. As part of the improvement of this linearity, there are several prior arts that devise propellers such as propellers at the stern and the surrounding linearity with respect to the propellers.

Patent Literature 1 discloses a ship equipped with a twin-skeg, by bending the lower portion of the skeg outward from the centerline of the hull to reduce the resistance of the skeg portion and improve the propulsion performance during navigation. Discuss the technical idea that it can.

However, this technique is merely conceived for the purpose of improving the propulsion force using the stern upward flow at the time of propulsion of the ship by reducing the skew shape and reducing the resistance of the skeg portion, thereby improving the propulsion efficiency of the ship. I do not have this in mind.

Patent Literature 2, in a ship provided with a twin-seg, does not block the upward flow in the stern flow generated on both sides of the skeg portion by providing horizontal pins on the left and right sides of each skeg. Disclosed is a technical idea that rectification is performed so as to weaken the downflow, the pressure loss caused by the downflow can be reduced, and the hull resistance can be reduced.

However, this technical idea is to reduce the pressure loss of the hull due to the rectification of the downstream of the stern flow, and is not related to the improvement of the propulsion efficiency of the ship.

Patent document 3 is a taper surface which inclines one side of the side part of the back side of the attachment case provided in the perpendicular direction to the front of the screw propeller which comprises the propeller of a ship in the same direction as the inclination direction of the blade of a screw propeller. By forming, the flow of water flowing in the outer circumferential side of the screw propeller is avoided by the tapered surface formed on the side of the side of the attachment case provided in front of the screw propeller, and the flow of the screw propeller is rotated. The technical idea that the compressed water can be directed toward the screw propeller from the reverse direction of. By this conveyed water, the state near the idling of the screw propeller is eliminated, and the rotating screw propeller increases the discharge amount to the rear, thereby increasing the propulsion efficiency of the ship and further improving fuel economy. It is said that it can contribute.

However, this technique is devised to alleviate any decrease in propulsion efficiency due to the flow avoiding the screw propeller caused by the presence of the attachment case located in front of the screw propeller. no.

Patent document 4 discloses the technical idea for solving the fault of a high speed boat. That is, in the high speed boats, propeller blades often generate propulsion force in the lower half of the water, and since the slow flow of the skeg is generated around the plane including the propeller shaft, sufficient propulsion force is generated. In addition, there is a drawback in that the propeller rotation reaction force cannot be sufficiently absorbed. Therefore, the technical idea which improves this fault is disclosed by attaching the thin prefabricated skeg made from the material with high strength eccentrically from the surface containing a propeller shaft.

However, Patent Document 4 is based on the premise of a high-speed boat as a use, keeping in mind that the surface of the upper half of the propeller is out of the water surface. For this reason, a technical field and a subject differ from this invention regarding the ship of the general transport use provided with the skeg. That is, the influence of the lower side of the housing of the drive shaft is not taken into consideration, and no countermeasure against efficiency reduction due to the influence of the casing of the gearbox which exists in about half of the water is taken. Moreover, since it aims at simply increasing the amount of water flow which hits a propeller, what was said to be the method of contact of the propeller rotation direction and a flow cannot be considered at all, and it does not actually raise the propulsion efficiency of a ship. In this respect, the intention of the present invention is different from that of the subject matter.

Patent document 5 has a stern outline structure in which the left and right symmetry is maintained except for the influence of the propeller shaft arrangement in a single-axis ship which generates a pair of left and right reverse rotation vertical swirls on the propeller surface as the ship proceeds. In the case of a right-turn propeller, the propeller has a propeller with a rotation center disposed at a position deviated from the hull centerline by a left-hand propeller, and the propeller rotates from both sides of the left and right pair of longitudinal swirls. And represents the technical idea of off-center-shaft ships configured to acquire reverse water flows on both sides of the rotation center, respectively.

According to Patent Literature 5, the propeller shaft is slightly displaced from the hull centerline while the hull shape maintains a linearly symmetrical linear line, and the water flow of the vertical whirlpool which causes the propulsion efficiency to decrease in the conventional ship having a large ship width. By increasing the propeller propulsion efficiency (approximately 10%), and the hull shape is almost symmetrical linear, the construction cost is lower and easier to design than the asymmetric linear line. do.

However, this patent document 5 is an example applied to the conventional type ship which has the stern part which a propeller shaft penetrates in front of a propeller, and is equipped with the 2-axis stern twin vessel or pod propeller which flows from the stern at all. This does not apply to technology.

Patent documents 6, 7, and 8 describe asymmetrical structure of a part of the stern of the upper part of the propeller shaft in order to improve fuel consumption by improving the flow of water to the screw (propeller) in a ship provided with one axis of the propeller shaft. And a combination of an asymmetrical and / or twisted stern portion having a spherical body or a U-shaped body at the lower part of the propeller shaft, and the technical idea of constructing the hull.

However, as shown in Patent Documents 6, 7, and 8, the propeller shaft is not positioned with an offset from the stern, and is also configured to bend the whole hull as a means for improving the flow of water to the screw. If adopted, the portion where the entire hull is bent becomes a resistance, which causes a decrease in propulsion efficiency. For this reason, the said structure is not necessarily effective as a means for improving the propulsion efficiency of a ship.

Patent document 9 shows the technical idea of improving the flow of water with respect to a propeller by forming a helical groove toward a stern propeller in a ship provided with one shaft of a propeller shaft.

However, as shown in Patent Literature 9, when a constitution in which a spiral groove is formed in the hull is used as a means for improving the flow of water to the propeller, the portion of the groove becomes a resistance and causes a decrease in propulsion efficiency. Becomes For this reason, the said structure is not necessarily effective as a means for improving the propulsion efficiency of a ship.

Patent document 10 is equipped with a movable pin for suppressing the vertical shaking of the hull at the rear end of the tunnel-shaped recess formed between the left and right hulls of the catamaran ship, so that the flow of water flowing into the fin can be accelerated. The tunnel-shaped concave portion discloses a shake reduction pinned catamaran that is formed such that its width gradually decreases from the bow portion to the stern portion.

However, this technique aims at reducing the vertical shake of the hull and is not related to the improvement of the propulsion efficiency of a ship.

Patent document 11 is a water jet propulsion which consists of a water intake port provided in the bottom surface of the left-right hull part from the stern part, the duct which reaches from the intake port to the water jet nozzle of the stern end, and the impeller interposed in the said duct. Disclosed is a technique related to a twin water jet propulsion vessel having a device.

However, this technique is constructed in such a manner as to form a bubble flow guide groove in the inward direction of the intake port, when the compressed air is pressed into the air cushion chamber by the lift fan and the ship is circumnavigated while floating the hull. This invention is intended to prevent leakage bubbles from entering the water intake port of the water jet propulsion device, which is different from the present invention.

Patent document 12 has the shape of a catamaran having a pair of elongated sidewalls on the left and right strings, and has a seal made of a flexible material at least at the fore end of the bow between the catamarans, Disclosed is a technique related to a pneumatically supported vessel with a side wall supporting most of the hull weight by collecting high pressure air in an air cushion chamber surrounded by a seal, and equipped with a flash type water jet as its propulsion device.

However, this technique is intended to prevent air intake from the water inlet of the water jet without lowering the air cushion pressure and sinking the hull by means of a lifting partition plate fence on both inner walls of the catamaran hull. Therefore, a subject differs from this invention.

Japanese Unexamined Patent Publication No. 2007-223557 : JP 2006-341640 : Japanese Utility Model Registration Publication No. 2604037 : US Patent No. 6,155,894 Japanese Patent Publication No. 04-046799 : Japanese Laid-Open Patent Publication No. 57-182583 US Patent Publication No. 4,538,537 US Patent Publication No. 3,455,263 US Patent Publication No. 4,363,630 : Japanese Patent Application Laid-Open No. 61-105292 : Japanese Patent Application Laid-Open No. 7-81550 : Japanese Patent Application Laid-Open No. 7-156791

The present invention is intended to solve such a prior art problem, and in particular, in order to effectively utilize the flow of water in the tunnel portion at the center of the stern of the two-axis stern catamaran type ship, the design of the tunnel portion between the stern shape and the skeg It is an object of the present invention to provide a two-axis stern catamaran vessel with improved propulsion efficiency.

The two-axis stern catamaran vessel of the present invention according to claim 1, comprising: a propulsion means for driving the two propellers to propel the two-axis stern catamaran vessel in a two-axis stern catamaran vessel having two propellers; And two skews provided on the hull of the two-axis stern twin-type vessel, and the centers of the driving shafts of the two propellers are offset from the center shafts of the two skegs, respectively. It is done.

According to the above configuration, by having a propeller whose center of the drive shaft has an offset from the center axis of the skeg, it becomes possible to use a flow in a direction opposite to the rotational direction of the propeller behind the skeg in a two-axis stern catamaran type ship. The return gain can be increased.

Here, the "two-axis stern catamaran vessel" is a vessel having a tunnel portion at the center of the stern where the lower hull (body) which sinks under the surface of water and directly contacts with water is long and parallel to the left and right sides. At least one propulsion means on the shaft; By using a two-axis stern catamaran type ship, the skeg provided for the stability of a ship body becomes small enough, and a loading space can also increase.

A propeller is a device for converting the output of propulsion means, such as an engine or a motor, into the propulsion force of a ship. For example, it propagates the output from a shaft while supporting a plurality of blades (blades) and blades for obtaining a propulsion force. It is good to comprise the hub and other components. As long as it has a rigidity that can withstand rotational force, fluid resistance, and the like and a property that can withstand constant immersion when used as a means for propulsion, any material such as metal, ceramic, resin, etc. may be used.

"Propulsion means" means means for driving a propeller to propel a ship, and means a main engine for driving a screw propeller, a double inverted propeller, a nozzle propeller, etc. used for a general ship, or Electric pod propeller by electric motor drive, pod propellers, such as a mechanical drive (Z drive), etc. may be included.

The 'skeg' is a 'fin' shaped structure extending in the vertical direction from the bottom. Even if it does not have a title called a skeg, it is included in this as long as it is an equivalence ship shape or operation which aims at stabilization of the path accompanying a ship advance, generally in front of a propeller.

The center axis of the skeg is, for example, the same as the line connecting the center of the cross section cut in a plane perpendicular to the direction in which the ship can be called a rough skeg from the ship front to the rear. The axis penetrates the inside of the skeg.

In general, the rotation axis of the propeller of the propulsion means and the center axis of the skeg are coincident with each other. In the present invention, the propeller is intended to improve the propulsion efficiency of the ship. This means that the center of the drive shaft is installed away from the center axis of the skeg.

The horizontal direction of the skeg means the inside or the outside of a pair of skegs.

The invention of claim 2 is characterized in that, in the biaxial stern twin vessel according to claim 1, the directions of the respective offsets are changed by respective rotational directions of the two propellers.

Here, 'change the direction of each offset by the rotation direction', for example, when viewed from the stern side, when the propeller rotates clockwise, the offset from the skeg to the right, the propeller rotates counterclockwise In this case, the offset from the skeg is changed to the left and right directions, such as to the left. For example, in a two-axis stern catamaran type vessel, when viewed from the stern side, the skeg on the left side is counterclockwise and on the right side due to the upward flow from the central tunnel-shaped bottom recess. In many cases, clockwise flow occurs in the skeg. In this case, the left propeller is offset in the right direction and the right propeller is offset in the left direction. This is intended to make the counter flow received by the propeller as large as possible by making the propeller rotate from the opposite direction with respect to the flow naturally occurring behind the skeg. In some ships, the rotational direction of the two propellers takes the same direction or the reverse direction, but the implementation of the present invention is not hindered even in such a ship.

According to the above configuration, the direction of the offset is set by adapting to the rotational direction of the propeller, so that the sum of the vector amounts of the counter flows that the propeller receives from the rotational surface can be made as large as possible.

The invention according to claim 3 is, in the biaxial stern catamaran vessel according to claim 1 or 2, wherein the width of the offset is almost the same as that of a circle around a circle drawn with a radius of 70 to 80% of the return distribution on the propeller plane. It is characterized by determining according to the point which becomes the maximum.

According to the above arrangement, the optimum offset width according to the shape and condition of the stern portion of the ship is derived, and the counter flow evaluated as the circulation behind the skeg captured by the propeller is maximized, so that the return gain is also large. The stern shape can be made.

The "reflux distribution in propeller surface" is the velocity distribution of the flow which flows into the propeller surface produced by the hull shape of a stern part, an adjunct, a structural part, etc. with propulsion of a ship here.

The point that becomes almost the maximum of the circumference of a circle circumscribed by a circle drawn with a 70-80% radius is, for example, a flow vector V _T to the propeller on the circumference of the circle drawn with a 70-80% radius of the propeller. Is defined by integrating on the circumference of the circle and finding this maximum as a function of the coordinates of the axis of rotation of the propeller.

Circulation refers not only to the circulation in fluid mechanics, which is obtained by integrating the product of the tangential direction and the line segment of each point along the closed curve in the flow, but also by using the vector of the flow along the circumference of the propeller. It is a concept that includes a broader meaning (referred to in the following description as `` a value equivalent to circulation ''), including a cyclically obtained one.

On the other hand, the integration is performed on the circumference of the circle drawn with a radius of 70 to 80% of the semicircular distribution to make the calculation simple and easy.However, in order to more accurately determine the coordinates of the optimum axis of rotation of the propeller, the circulation is performed on the entire surface of the propeller surface. The maximum value may be calculated by calculating the propulsion force of the propeller surface.

According to a fourth aspect of the invention, in the two-axis stern twin vessel of claim 1 or 2, the rotation direction of the propeller driven in two axes is located on the left side when the two-axis stern twin vessel is viewed from the stern side. The propeller to the clockwise rotation, characterized in that the propeller located on the right side is set to the counterclockwise rotation.

This effectively increases the return gain by effectively acting on the propeller the flow symmetrically generated on the skew of a two-axis stern twin-type ship, and also prevents unbalanced forces caused by rotation in the same direction on the hull. Because of this, it contributes to the stable navigation of the ship. Here, the "propeller driven in two axes" means that two propellers are rotated by different drive shafts rather than having two propellers on one rotation shaft.

According to a fifth aspect of the invention, in the biaxial stern twin vessel of claim 1 or 2, the rear portions of the two skgs are twisted in a direction opposite to the rotational direction of the two propellers.

Here, the term 'biton opposite to the rotation direction' refers to a case in which the skeg is deformed counterclockwise, for example, when the propeller is rotated clockwise when viewed from the rear of the ship. , When the flow of water formed along the surface of the skeg is seen from the rear of the ship, it is referred to as counterclockwise rotation. As a result, the flow in the rotational direction and the reverse direction with respect to the propeller can be rotated to act.

Deformation includes all forms that change or change the shape of the skeg. That is, the twisted shape in the opposite direction to the rotational direction of the propeller of the skeg may take a form that is gently bent from the front of the skeg, or may be a shape that is sharply bent near the back of the skeg, while completing the original function of the skeg. It may be a shape that generates a flow that is a rotational flow effective for propeller propulsion efficiency without increasing the frictional resistance that much. The forming method may be formed integrally with the same material as the bottom, or may be detachable as a separate part from the bottom so that the slag can be replaced. The material is free of any metal, plastic, ceramic, or the like as long as it can achieve the purpose of continuously generating the rotating flow stably. According to the above configuration, by applying a twist to the skeg, it is possible to maximize the counter flow hitting the propeller by applying the vector of the flow to the propeller more effectively.

According to a sixth aspect of the present invention, in the two-axis stern twin vessel of claim 1, the propulsion means includes two pod propellers.

Here, the "pod propeller" also refers to a propeller or a mechanical Z drive which has an electric motor in a spindle-shaped hollow container and rotates the propeller by electric power. The positional relationship between the skeg and the propulsion means is freely to some extent. Propulsion means that can be set.

According to the above arrangement, the offset width from the center axis of the skeg can be set with a considerable degree of freedom as compared with the method of having the drive shaft of the propeller in the skeg.

According to a seventh aspect of the present invention, in the biaxial stern twin vessel of claim 6, the connecting portion for connecting the pod propeller in the transverse direction of the skeg is provided.

According to this structure, since the connection part which connects a pod thruster is provided in the horizontal direction of a skeg, a connection part can be comprised small compared with the case where it connects in a longitudinal direction.

The invention of claim 8 is characterized in that the pod thruster is electrically driven in the two-axis stern twin vessel described in claims 6 or 7.

By using an electric drive type as the pod propeller, since the mechanism for rotating the propeller can be made smaller as compared with the case of using a mechanical Z drive, for example, the connection portion connecting the pod propeller to the skeg is reduced. can do.

According to a ninth aspect of the present invention, in the two-axis stern catamaran vessel described in claim 1 or 2, the propulsion means is a main engine for driving the two propellers, and the projecting portion for receiving the drive shaft of the propeller It characterized in that the provided in the horizontal direction of the skeg.

Here, the "main engine" refers to a device such as an engine that continuously generates mechanical energy. For example, when the two propellers are driven by different main engines, the number of main engines provided by the two-axis stern twin vessel of the present invention is two. However, it is not necessary to have two main engines, and it can also be set as the structure which drives two propellers by one main tube.

According to the said structure, since the skeg is provided with the protrusion part which accommodates the drive shaft of a propeller in the transverse direction of a skeg, it does not need to provide the structure which accommodates the drive shaft of a propeller in particular, and can also comprise a small protrusion.

The invention of claim 10 is a two-axis stern catamaran vessel having two skegs at the stern and two propellers driven in two axes, comprising: a boundary layer suction port provided in a tunnel portion formed between the two skags, and the boundary layer. And suction means for sucking water from the suction port, and a discharge port for discharging water sucked by the suction means.

Boundary layer refers to an area that is delayed when the ship proceeds under the influence of friction with the ship bottom. In other words, in fluids with low viscosity, such as water, the theory of perfect fluid that ignores viscosity is generally true, but the boundary layer is an area where the velocity gradient near the surface of the object is large and the viscosity cannot be ignored.

The boundary layer suction port may be any one that sucks water in the boundary layer, and includes water in the boundary layer and water other than the boundary layer. In addition, although the boundary layer suction port preferably sucks all the water in the boundary layer, even if the boundary layer water only sucks water near the outer surface of the ship bottom, the influence on the resistance of the biaxial stern catamaran vessel is particularly large. good.

Invention of Claim 11 WHEREIN: In the biaxial stern twin boat of Claim 10, the said boundary layer suction port is provided in the vicinity of the inlet part of the said tunnel part.

Here, the "entrance part of a tunnel part" means the bow side end of a ship bottom among the surfaces which comprise the tunnel part formed by a ship bottom and two skews.

Invention of Claim 12 WHEREIN: In the biaxial stern twin boat of Claim 1 or 2, the width dimension of the said boundary layer suction opening was set to the approximate width dimension of the said tunnel part.

Here, the "width dimension" of a tunnel part means the dimension of the line width direction of the tunnel part formed between two skews provided in the stern.

According to a thirteenth aspect of the present invention, in the biaxial stern catamaran type vessel of the tenth or eleventh aspect, the angle of the inclination angle formed by the outer surface of the tunnel portion with respect to the horizontal direction is 15 degrees or more.

According to a fourteenth aspect of the present invention, in the two-axis stern twin vessel of claim 10 or 11, the two-axis is provided by changing the amount of the water discharged from the two discharge ports. It is characterized by carrying out shipbuilding of the stern double catamaran vessel.

According to a fifteenth aspect of the present invention, in the two-axis stern twin vessel of claim 14, two suction means are provided in a path from the boundary layer suction port to the discharge port, and the two suction means are controlled by controlling the two suction means. It is characterized in that the amount of water discharged from the two discharge ports is changed.

According to a sixteenth aspect of the present invention, in the two-axis stern catamaran type vessel according to claim 14, the movable section is provided with a movable portion for changing the flow formed by the suction means in a path from the boundary layer suction port to the discharge port. By changing the amount of water discharged from the two discharge ports.

Here, the 'moving part for changing the flow' is a vane-shaped moving part for changing the ratio of the amount of water discharged from two discharge ports installed in the path, for example, the amount of each water discharged from the two discharge ports. It refers to the whole structure having a movable part which changes a flow and has substantially other than a suction means, such as a valve which controls this.

According to the present invention, by using a two-axis stern catamaran type ship, the skeg provided for the stability of the hull is small enough, and the influence on the return as an obstacle in front of the propeller is reduced, and the scale is offset by the offset. It is possible to increase the vector component of the flow which acts effectively with respect to the propeller with respect to the propeller at the rear, and can provide a preferable ship from the viewpoint of energy saving which improved propulsion efficiency.

In other words, if the rotational center of the propeller is set to have a position offset from the center axis of the skeg, the propeller may increase the sum of the vector amounts of the counter flows received from the rotational surface, and the upward flow formed in the tunnel portion is used to counter the propeller. Since it can be used effectively as a flow, the propulsion efficiency of a two-axis stern catamaran type ship can be improved.

In addition, by setting the direction of the offset by adapting to the rotational direction of the propeller, it is possible to maximize the total sum of the vector amounts of the counter flows received by the propeller on the rotational surface, thereby maximizing the propulsion efficiency.

Moreover, based on the circulation of the flow, by deriving an optimum offset width according to the shape and state of the stern part of the ship, propulsion efficiency can be reliably improved by utilizing the counter flow behind the skeg captured by the propeller. .

In addition, the direction of rotation of the propeller driven in two axes is seen from the stern side of the two-axis stern catamaran vessel, and the propeller located on the left side is turned clockwise and the propeller located on the right side is turned counterclockwise. In this configuration, since the upward flow formed in the tunnel portion can be effectively used as a counter flow of the propeller, it is possible to improve the propulsion efficiency of the two-axis stern twin vessel.

In addition, by twisting the rear portion of the skeg and acting the flow in the reverse direction to the propeller, the counter flow that reaches the propeller can be increased, thereby maximizing propulsion efficiency.

In addition, by using the pod propeller, the structure and the additives for driving the propeller in front of the propeller can be eliminated, so that adverse effects on the backflow as an obstacle in front of the propeller can be reduced, and the offset width is considerably free. Since it can be set, the propeller can be made to come in the optimal position after improvement of propulsion efficiency.

Moreover, since the connection part which connects a pod propeller is provided in the horizontal direction of a skeg, a connection part can be made small compared with the case where it connects in a longitudinal direction. In this way, by forming the connecting portion with a small one, the frictional resistance caused by the connecting portion when the biaxial stern catamaran vessel is propelled can be reduced, and the connecting portion can be provided at low cost.

In addition, since the connection portion can be made smaller by using an electric drive type as the pod propeller, it is possible to realize that the frictional resistance due to the connection portion when the two-axis stern catamaran vessel propels is smaller.

In addition, the propeller can be arranged at a position offset horizontally from the center axis of the skg by accommodating the drive shaft in the projection provided in the horizontal direction of the skeg. For this reason, a protrusion can also be comprised small, the frictional resistance resulting from the structure which accommodates the drive shaft when a two-axis stern double catamaran ship propels can be made small, and a two-axis stern catamaran ship can be provided at low cost. .

In addition, by sucking the water of the boundary layer at the boundary layer suction port provided in the tunnel portion, the separation of the boundary layer from the outer surface of the tunnel portion can be suppressed. Thereby, it can suppress that a boundary layer peels and a flow reverse to normal is formed, and the increase of resistance can be suppressed. Accordingly, it is possible to realize an improvement in propulsion performance of a two-axis stern twin vessel.

When the boundary layer suction port is provided near the inlet of the tunnel, the slope of the ship bottom changes abruptly, so that the boundary layer can be sucked from the near side of the area in the area where the boundary layer is likely to peel off. Therefore, peeling of a boundary layer from the outer surface of a tunnel part can be suppressed effectively.

 In addition, if the width dimension of the boundary layer suction port is set to the approximate width dimension of the tunnel portion, the boundary layer can be sucked over the entire tunnel portion, so that the boundary layer can be effectively prevented from peeling off from the outer surface of the tunnel portion.

In addition, when the angle of the inclination angle formed by the outer surface of the tunnel portion with respect to the horizontal direction is set to 15 degrees or more, it is possible to set the starting point of the inclination of the ship bottom to the stern side than the conventional one. As a result, the load of the biaxial stern catamaran vessel can be increased, and the transportation efficiency thereof can be improved.

In addition, if two discharge ports are provided and the quantity of water discharged from these is changed, for example, a biaxial stern twin ship can be manufactured without operating a pod propeller or steering means.

In addition, by changing the amount of water discharged from the two discharge ports by controlling the two suction means, the shipbuilding effect can be enhanced along with the change in the suction amount of the boundary layer suction port.

In addition, by changing the amount of water discharged from the two discharge ports by controlling the movable portion, for example, even if there is only one suction means, a two-axis stern catamaran type ship can be built.

BRIEF DESCRIPTION OF THE DRAWINGS The external view which looked at the 2-axis stern twin type ship which concerns on Embodiment 1 of this invention from the inclination rear side.
2 is a conceptual diagram showing the positional relationship between the skeg and the pod propeller used in the ship of FIG.
3 is a schematic diagram schematically showing a flow around a stern of a conventional single axis.
4 is a schematic diagram showing a flow around a two-axis stern catamaran vessel skeg according to Embodiment 1 of the present invention.
It is a schematic diagram which shows the outline which looked at the biaxial stern double catamaran ship which concerns on Embodiment 2 of this invention from the back.
6 is a cross-sectional view taken along line C1-C2 of the stern vicinity of the two-axis stern catamaran vessel of FIG.
It is a schematic diagram which shows the outline which looked at the biaxial stern double catamaran ship which concerns on Embodiment 3 of this invention from the back.
FIG. 8 is a schematic view for explaining the interior of the two-axis stern catamaran vessel skeg of FIG. 7. FIG.
9 is a schematic diagram showing the propulsion distribution of a general propeller.
10 is a vector and a return distribution diagram of flows in front of a propeller according to Embodiment 4 of the present invention.
11 is a contour diagram of a circulation diagram showing an optimum position of a propeller drive shaft according to Embodiment 4 of the present invention.
12 is a three-dimensional overhead view of a cycle according to Embodiment 4 of the present invention.
It is sectional drawing which shows typically the state which cut | disconnected the vicinity of the stern part of the biaxial stern twin boat of Embodiment 5 of this invention in the front-back direction in the vicinity of the center.
It is a schematic diagram which shows the outline of the structure which looked at the 2-axis stern twin type ship of Embodiment 5 of this invention from the back.
It is a schematic diagram which shows the outline of the state which looked at the tunnel-shaped recessed part of the biaxial stern catamaran ship of Embodiment 5 of this invention from the bottom of the ship.
It is a schematic diagram which shows the outline of the state which looked at the tunnel-shaped recessed part of the biaxial stern catamaran ship of Embodiment 6 of this invention from the bottom of the ship.
It is a schematic diagram which shows the outline of the state which looked at the tunnel shape recess of the biaxial stern double catamaran ship in the 6th Embodiment of this invention from the bottom of the ship.
It is a schematic diagram which shows the outline of the structure which looked at the 2-axis stern twin type ship of Embodiment 7 of this invention from the back.
It is a schematic diagram which shows the outline of the structure which looked at the 2-axis stern twin type ship of Embodiment 8 of this invention from the back.
20 is a cross-sectional view schematically showing a state in which the vicinity of the stern portion of a conventional two-axis stern catamaran vessel is cut in the front-rear direction near the center thereof.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention with reference to drawings is demonstrated. In addition, below, the range required for description for achieving the objective of this invention is shown typically, The range required for description of the said part of this invention is mainly described, and about the place which abbreviate | omits description, according to well-known technique Shall be.

(Embodiment 1)

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view which looked at the biaxial stern catamaran ship which concerns on Embodiment 1 of this invention from the inclination rear side. As shown in the figure, the hull 1, the skeg 11, the skeg 12, and the pod propeller 210 and the pod propeller 220 installed immediately behind are provided in pairs and at the stern. It is. If there is a gap between the axial line of the propeller 210 and the axial line of the skeg 11 represented by the dotted lines, this is offset 2A, and the gap between the axial line of the propeller 220 and the axial line of the skeg 12. Are present, they are denoted by offset 2B, respectively. On the other hand, a two-axis stern catamaran vessel having a pod propeller is an example, and a two-axis stern catamaran vessel through which a normal shaft penetrates does not hinder the implementation of the present invention at all.

2 is a configuration diagram showing the positional relationship between the skeg 11 and the pod propeller 210 as seen from the rear of the hull 1. In the figure, the skeg employed in the present embodiment is adopted for the wedge shape (herein referred to as a Cocuria linear shape). The propeller 2101 of the pod propeller 210 rotates clockwise during propulsion to generate propulsion force. The skeg 11 on the left side is bent in the transverse direction as seen in the cross section as shown in the drawing. The upper portion is bent to the left from the center shaft 11A of the skeg and the lower portion to the right from the center shaft 11A, respectively. As a result, the flow from the right side to the left side is increased from the center shaft 11A of the skeg to the upper portion from the rear of the hull 1 due to the upward flow, and from the center shaft 11A of the skeg to the lower portion, Since the flow from the left side to the right side can be strengthened as seen from the rear of the hull 1 due to the upward flow, the counter flow to the propeller 2101 can be increased.

11 A of center shafts of a skeg are the lines which, for example, the line which connected about the center of the cross section which cut | disconnected the part which can be called substantially skeg in the said ship in the plane perpendicular | vertical to the traveling direction of a ship, from the front of a ship to the back, Likewise, the axis penetrates the inside of the skeg.

As shown in FIG. 2, the propeller shaft center 2101A of the pod propeller 210 is provided with an offset from the shaft center 11A of the torsionally applied skeg 11. The offset is a shift intentionally provided for the purpose of obtaining a hydrodynamic effect.

FIG. 3: is a schematic diagram which shows the flow around the stern of the conventional one axis conventionally, and FIG. 4 is a schematic diagram which shows the flow around the skg which concerns on Embodiment 1 of this invention.

As shown in Fig. 3, in the general stern portion 31 of the uniaxial line, when the ship propels, a clockwise flow 35A is formed on the left side of the stern portion and a counterclockwise flow 35B is formed on the right side of the stern portion. have.

Generally, when the drive shaft 311A of the propeller is provided on the longitudinal center line 311 of the stern part 31, and the propeller (not shown) of clockwise rotation is provided ( On the left side of the stern), the flow 35A in the same direction as the rotation of the propeller occurs on the left side, and on the right side (viewed from the rear of the stern), the flow 35B of the propeller rotation and the reverse direction occurs. Since the propulsion force generated from the propeller is maximum when the flow in the direction reverse to the rotation direction of the propeller is maximized, the propulsion force applied to the ship is more generated on the right side of the propeller when viewed from the right and left of the propeller.

In the case of a skeg, since the shape is small and the width | variety is also narrow compared with the stern part of this general uniaxial line, the wake of a skeg does not become the flow defined by the vortex.

In the case of a normal two-axis stern catamaran type vessel, the stern shape characteristic of having a skew differs from the stern portion of the general one axis, and the central tunnel-shaped hull recess (it is appropriately referred to as 'tunnel portion'). The counterclockwise flow occurs near the skeg 11 on the left side, and the clockwise flow occurs near the skg 12 on the right side. When viewed from the rear of the stern of the hull, it can be said that the flow in the opposite direction to the above-mentioned stern of the general one-axis line is generated, respectively.

In FIG. 4, the shape of the skeg 11 of the left side seen from the back among two skews in the biaxial stern catamaran vessel which concerns on this invention is shown.

The skeg 11 on the left side is gently twisted from the front of the hull. When the ship moves forward, natural flows 15A and 15B occur along the upward flow along with the upward flow, but due to the twisted shape of the skeg 11, in addition to the stern shape of the two-axis stern twin type ship, In the right 11B of the skeg 11, the flow 15B of counterclockwise rotation becomes strong, and the area | region which becomes rotational flow arises. By bringing a propeller into this area, the counter flow of the upward flow F (refer FIG. 5) which a propeller receives in the right half R1 of the rotating surface becomes stronger, and a return gain can be increased.

(Embodiment 2)

When considering future marine propulsion systems that do not rely on fossil fuels, Ford propulsion, which is based on electric propulsion, is the most successful and reliable of the current propulsion systems. On the other hand, the biggest drawback of electric propulsion is its energy conversion efficiency and is currently thought to be about 12 to 13% of loss. Therefore, it is unavoidable to be 10 to 11% disadvantageous as compared with the conventional diesel engine propulsion directly connected to the main engine having only 1 to 2% transmission loss. To solve these problems, it is necessary to carry out a linear design that takes full advantage of the characteristics of Ford propellers.

In the biaxial stern twin vessel of this embodiment, a pod strut (connecting portion) for attaching the offset pod propeller is provided in the transverse direction of the skeg to substantially reduce the frictional resistance of the pod strut. For this reason, the propulsion efficiency of a biaxial stern double catamaran ship can be improved by reducing the frictional resistance of a pod strut.

FIG. 5: is a schematic diagram which shows the outline of the structure which looked at the biaxial stern double catamaran ship which concerns on Embodiment 2 of this invention from the rear. As shown in the figure, a pair of scoops 11 and 12, and a pair of pod propellers 210 respectively provided at the stern portion 13 of the hull 1, immediately behind them. Pod thruster 220 is provided.

The gap between the shaft center line 2101A of the propeller 2101 and the center shaft 11A of the skeg 11 represented by x is offset 2A, and the shaft center line 2201A of the propeller 2201 and the skeg ( The gap with the center axis | shaft 12A of 12 is respectively represented by the offset 2B. On the other hand, a two-axis catamaran stern-shaped vessel (two-axis stern catamaran vessel) having a pod propeller is an example, and as shown in Embodiment 3 described later, a vessel having a two-axis catamaran stern shape through which a drive shaft penetrates. Even in the case of a two-axis stern catamaran type vessel, the implementation of the present invention is not impeded.

When the biaxial stern catamaran vessel according to the second embodiment propels, the tunnel-shaped concave portion near the stern portion 13 surrounded by the bottom 11 of the skeg 11, the skeg 12, and the hull 1 Within 14, a strong upward flow F in the direction of the stern portion 13 (the front direction in FIG. 5) indicated by the broken-line arrow in FIG. 5 occurs. This is because the bottom of the hull 1 surrounding the tunnel-shaped recess 14 as shown in the cross-sectional view of FIG. 6 cut along the C1-C2 line of the stern portion 13 of the two-axis stern catamaran vessel. 20 is inclined rapidly so as to rise toward the stern portion 13. For this reason, below the draft line L shown by the broken line in the figure, with the propulsion of the ship body 1, the upward flow F in the inclined upper direction according to the inclination of the ship bottom 20 generate | occur | produces. In addition, in order to offset the pod propeller 220 from the center axis of the skeg 12 to a predetermined position, the connecting portion 24 connected in the vertical direction as shown by the imaginary line using a dashed line in the figure is provided. It is necessary. In other words, the connecting portion 24 is required to be long in the longitudinal direction, and also inevitably increases in cross-sectional area in order to secure momentary strength, and as a result, the surface area of the connecting portion 24 becomes very large. Exposure of the connecting portion 24 to the upward flow F causes a large frictional resistance, thereby lowering the propulsion efficiency. This also applies to the other pod propeller 210.

Therefore, as shown in FIG. 5, in the two-axis stern catamaran vessel of the second embodiment, the pod propeller 210 and the pod propeller 220 are moved in the horizontal direction of the skeg 11 and the skeg 12. By connecting to each other, the surface area of the connecting portion is made small, thereby reducing the frictional resistance by exposing the connecting portion to the upward flow (F).

That is, the pod propeller 210 has the skeg 11 across the pod strut (connection part) 21 provided in the inner side of the skeg 11 (a side which becomes the right side of the skeg 11 when viewed from the rear). ), And the pod propeller 220 has a pod strut (connecting portion) 22 provided inside the skeg 12 (side that becomes the left side of the skeg 12 when viewed from the rear). It is connected to the skeg 12. The position at which the pod propellers 210 and 220 are offset so that the pod propellers 210 are offset is usually closer to the skegs 11 and 12 than the ship bottom 20. For this reason, the pod struts 21 and 22 are connected to the bottom 20 in the longitudinal direction by connecting the pod propellers 210 and 220 to the inner side of the skegs 11 and 12 (see Fig. 6). ) Can be made small. That is, by connecting the pod struts 21 and 22 in the transverse direction of the skegs 11 and 12, the surface area can be set extremely small as a result. In addition, the flow of the upward flow F is slower between the pod propellers 210 and 220 and the skegs 11 and 12 than between the pod propellers 210 and 220 and the bottom 20.

Therefore, by installing the pod struts 21 and the pod struts 22 in the transverse directions of the skegs 11 and 12, the surface area can be configured to be extremely small and can be arranged in the late flow part. have. Thereby, the pod strut 21 and the pod strut 22 which connect the offset pod thruster 210 and the pod thruster 220 to the hull 1 are due to exposure to the upward flow F. The resistance can be made small. In addition, since the pod strut 21 and the pod strut 22 can be configured small, they can be provided at low cost.

As indicated by the arrows in FIG. 5, the propeller 2101 of the pod propeller 210 and the propeller 2201 of the pod propeller 220 rotate in opposite directions. More specifically, the pod propeller 2101 is rotated clockwise when viewed from the rear, and the propeller 2201 is rotated counterclockwise when viewed from the rear, and is rotated so-called inwardly. For this reason, the pod propeller 210 can use the upward flow F as a counter flow in the area | region R1 of the right half of the rotation surface of the propeller 2101 shown by the circle | round | yen using a dashed-dotted line in the figure. Similarly, the pod thruster 220 can use the upward flow F as a counter flow in the area L2 of the left half of the rotation surface of the propeller 2201 shown by the circle | round-dotted line in the figure. On the other hand, the counter flow refers to the flow of water in a direction opposite to the rotation direction of the propeller. By using this counter flow, the loss caused by the propeller rotating water can be reduced, and the propulsion force can be improved.

Moreover, most of the area | region L1 of the left half of the rotating surface of the propeller 2101 is located in the area | region where the flow of water of the back of the skeg 11 and the pod strut 21 is late. In addition, most of the region R2 of the right half of the rotating surface of the propeller 2201 is similarly located in the region where the water flow is late. For this reason, in the area | region where the upward flow F cannot be used as a counter flow, it is hardly influenced by the offset. Therefore, by offsetting the shaft center line 2101A of the propeller 2101 from the center axis of the skeg 11, it is hardly adversely affected by the upward flow F. As shown in FIG. The same applies to the propeller 2201.

Therefore, since the upward flow F can be used as a counter flow by offsetting the propellers 2101 and the propellers 2201, the driving force is greatly improved.

Thereby, since the upward flow F resulting from the inclination of the bottom 20 near the stern part 13 can be used for the improvement of propulsion force, the inclination of the bottom 20 can be enlarged. Therefore, the starting point of the inclination of the ship bottom 20 in the vicinity of the stern part 13 can be made to be rearward | backward than before, and the loading amount of a biaxial stern twin-type ship can be enlarged.

As described above, the biaxial stern catamaran vessel of the second embodiment offsets the propeller 2101 and the propeller 2201 from the center shafts of the skeg 11 and the skeg 12 to improve the propulsion efficiency. It is an improvement. Moreover, since the pod strut 21 and the pod strut 22 are provided in the transverse direction of the skeg 11 and the skeg 12, they minimize the frictional resistance by exposing them to the upward flow F. You can do

On the other hand, in the present embodiment, the upward flow F of the tunnel-shaped recess 14 is offset by offsetting the propellers 2101 and the propellers 2201 in the inward directions of the skegs 11 and 12. Although the propulsion force is improved by using, the effect of counter flow is lowered when the propeller 2101 and the propeller 2201 are offset in the outward directions of the skeg 11 and the skeg 12, but the two-axis stern twin The straightness of the type ship can be improved.

(Embodiment 3)

The two-axis stern catamaran vessel of the third embodiment changes the pod thruster used as the propulsion means in the second embodiment to a normal main engine direct thruster. The optimum position of the propeller is located at a position offset greatly inward from the center axis of the skeg. However, in a typical skeg shape, disposing the propeller of the main engine direct propeller at that point has a special structure for accommodating the drive shaft of the propeller. It is difficult to install. Therefore, the two-axis stern catamaran vessel of the present embodiment has a large asymmetry in the skeg shape, and provides a protruding portion extending inwardly to accommodate the propulsion shaft of the main engine direct propeller therein, whereby the main engine direct connection type In the case of using a propeller, a purpose of obtaining high propulsion efficiency is similarly achieved in the case of using a pod propeller. Specifically, in order to offset the center position of a propeller largely from the center of a skew to a ship hull center side, a skew shape is made asymmetrical and a protrusion is provided inward large.

FIG. 7: is a schematic diagram which shows the outline which looked at the biaxial stern catamaran vessel which concerns on this Embodiment 3 from the back. As shown in the figure, a pair of the skeg 51 and the skeg 52, just behind these, are provided in the stern portion 53 of the hull 50 of the two-axis stern catamaran type ship of the present embodiment. A pair of main engine direct propeller 310 and a main engine direct propeller 320 are provided, respectively. In the figure, the gap between the shaft center line 3101A of the propeller 3101 and the center shaft 51A of the skeg 51 is offset 3A, and the shaft center line 3201A of the propeller 3201 and the skeg ( The gap with the center axis 52A of 52 is indicated with the offset 3B, respectively.

The biaxial stern double catamaran ship of this Embodiment 3 is similar to the biaxial stern catamaran ship of Embodiment 2, when pushing, the ship bottom 51 of the skeg 51, the skeg 52, and the hull 1 In the tunnel-shaped recess 54 in the vicinity of the stern portion 53 enclosed by the edge, a strong upward flow F in the stern portion 53 direction (front direction in FIG. 7) occurs. In order to use this upward flow F as a counter flow, it is necessary to offset the propeller 3101 and the propeller 3201 to the inside of the center shaft 51A and the center shaft 52A. However, when the skeg 51 and the skeg 52 are made into a general conventional skeg shape, the propeller 3101 and the propeller 3201 cannot be offset. Therefore, the protrusion 51 and the protrusion 62 which accommodate the drive shaft of the propeller 3101 and the propeller 3201 are provided in the skeg 51 and the skeg 52 inside.

Thus, the propeller 3101 and the protrusion part 62 and the protrusion part 62 which extend in the inner side (tunnel-shaped recess 54 side) of the skeg 51 and the skg 52 are provided. It is possible to arrange the propeller 3201 at an optimal position in order to improve the propulsion efficiency by using the upward flow F. FIG.

FIG. 8 is a view showing the skeg 52 of the two-axis stern catamaran vessel of FIG. 7 as seen from the center of the hull, and is a schematic diagram for explaining the interior of the skeg. The skeg 52 is provided with the protrusion part 62 extended inward. For this reason, as shown by the broken line in the figure, in the state where the propeller 3201 is offset, the drive shaft 3202 for driving the propeller 3201 and the main engine 3203 connected to the propeller 3202 therein. It may be provided. The same applies to the other propeller 3101.

As described above, the biaxial stern catamaran vessel of the third embodiment is designed to have a skeg shape, so that even if the structure for accommodating the drive shaft of the propeller is not particularly provided, the optimum position on the propulsion efficiency that has been difficult in the past, namely, The propeller of the main engine direct propeller was arrange | positioned at the position offset large inward. In the two-axis stern catamaran vessel of the third embodiment, by using the upward flow F as the counter flow, the frictional resistance accompanying the increase in the surface area of the projections 61 and 62 extending in the lateral direction is far exceeded. The improvement in propulsion efficiency can be aimed at. Further, by making the skeg bite Kokuria linear, the counter flow effect can be further increased, and the surface area of the protruding portions 61 and 62 extending in the lateral direction can be reduced, and the propulsion efficiency can be further improved.

In a two-axis stern catamaran vessel equipped with a main engine as in the third embodiment, by devising a projecting portion for accommodating a skew shape and a driving shaft, the structure is inexpensive due to a small projecting portion without special installation of the structure for accommodating the driving shaft. At the same time, there is an advantage that can reduce the cost increase required for the equipment of the Ford propeller.

(Embodiment 4)

Next, a method for obtaining the optimum point for installing the rotating shaft of the propeller by an algorithm will be described. This method can be used for any of the two-axis stern catamaran vessels of Embodiments 1 to 3 described above.

It is a schematic diagram which shows the propulsion force distribution of a general propeller.

The blade surface of the propeller has a trade-off relationship in that, when the area is large, the driving force generated at the time of rotation increases, but the resistance received from the water increases accordingly. From the calculation, the point where the maximum driving force is generally known is that the distance from the rotational axis is in the range of 70 to 80% of the rotation radius of the propeller. However, depending on the propeller shape, the position of the peak at which the propulsion force is maximized may be different. However, it is an object of the present invention to make the rotation flow generated from the front of the propeller reach the propeller as a counter flow as much as possible. This propeller does not interfere with the implementation of the present invention.

FIG. 10: is a vector and the return flow chart of the water flow in the back (front surface of the propeller 2101) of the skeg 11 which concerns on Embodiment 4 of this invention. The vector of the flow may be obtained by measuring physically, for example, in an experimental facility or the like, or may be obtained as a result of model experiments, computer simulations, or the like. Means of means are not required as long as they meet the premise that they can be obtained in close form during actual operation of the ship equipped with the system.

As shown in the figure, it is understood that the skew to which the torsion is applied has an asymmetrical flow, and on the right side, an area where the large flow of the vector widens in the counterclockwise rotation is widened. This counterclockwise rotation flow can be said to be a counter flow, that is, a rotational flow, which improves propulsion efficiency of the propeller. In order to make the area which a propeller of a clockwise rotation touches this counterclockwise rotation flow as much as possible, the offset of a right direction is provided in the rotating shaft of a propeller. In addition, the optimum position of the propeller is set slightly above the horizontal line passing through the shaft center of the skeg in addition to the offset in the right direction.

The functional block concerning embodiment for offset position optimization of a propeller drive shaft is demonstrated (not shown).

This embodiment is, for example, a flow vector data input unit for inputting and holding a vector of a flow generated behind a skeg obtained by experiments or simulations, and a range in which propellers rotate to generate propulsion in water as the radius of the propeller. The drawing part of the maximum thrust circle which draws the radius input part which inputs and maintains, and the trajectory (maximum thrust circle R) of the circle which generate | occur | produces the maximum thrust force which is about 70-80% of radius from the input radius. And the maximum thrust circle R center coordinate control unit which continuously changes the value of the center coordinate of the maximum thrust circle R and passes it to the drawing part of the maximum thrust circle, the coordinates on the maximum thrust circle R, and the maximum thrust circle R on the rotational flow vector data. the flow vector V stream for deriving a _T V _T vector derivation unit, both the overall flow vector V _T on the maximum driving force source R And the line integral of the flow vector integration section V _T across, and by comprising a graph plot to plot a graph from the results of the center coordinates and the shipment of the maximum driving force source R, configuration (not shown).

On the other hand, this embodiment is implemented as software, for example, and various modifications are possible about the function which each functional block is in charge, and the details of mutual connection. What is necessary is just an algorithm which calculates the optimal coordinate position of the rotating shaft of a propeller based on a circulation. In addition, each component of the above software may be a machine, an apparatus, a component, or an algorithm that causes a computer to execute these functions, a program that executes the algorithm, or software including the program, This is realized by a loading medium, a ROM (read-only memory), or a computer equipped with or embedded therein. In addition, a computer device (including a personal computer (PC)) equipped with these devices includes a central processing unit (CPU) that performs data processing or calculation, an input unit (keyboard, etc.) that performs predetermined data input, and input data or data processing. Information with a screen display (display, etc.) for displaying results, a storage device (memory, a hard disk drive, etc.) for storing various data, a connector (USB, RS232C, etc.) for connecting to a predetermined external device, etc. Processing device).

In order to find out the optimum point for installing the rotating shaft of a propeller, the following sequence can be outlined (not shown). In other words, first, flow vector data is obtained. The flow vector data input unit inputs a vector of flow generated behind the skeg obtained by experiment or simulation. Next, the radius input section inputs and maintains the range in which the propeller rotates to generate propulsion in the water as the radius of the propeller. Next, the drawing part of the maximum propulsion force circle draws the trajectory (maximum propulsion circle R) of the circle which generates the maximum propulsion force in the vicinity of the approximately 70-80% radius from the input radius. The maximum thrust circle R center coordinate control unit continuously changes the value of the center coordinate of the maximum thrust circle R and passes it to the drawing unit of the maximum thrust circle. And then derives a flow vector V _T by the derivation unit, the maximum driving force source coordinates and the R times _T V flow vector from the current vector on the data. Here, the flow vector V _T means a component in the tangential direction of the maximum thrust circle R of the rotational flow vector in the coordinate on the maximum thrust circle R. Next, the flow vector V _T is loaded and distributed over the entire circumference on the maximum thrust circle R by the flow vector V _T integrating unit. Next, a graph is plotted (not shown) by the graph plotting unit from the center coordinates of the maximum driving force R and the result of shipment. In this way, the graph is plotted to obtain the contour line. The maximum point of this contour is set as the optimum position.

On the other hand, the above-described vector of flows may be created from, for example, results measured physically in an experimental facility, or may be obtained as a result of model experiments, computer simulations, or the like. As long as it satisfies the premise that it can be obtained in a close form during actual operation of the ship equipped with the skeg 12, any means of the means is not required.

As described above, the flow vector V _T integral addition, to the flow vector V _T at the point (x, y) on the circumference of the maximum driving force source R, as long as one revolution on the circumference, only performing the integration, obtained by this A possible value is called a circulation (equivalent value). On the other hand, with respect to the value corresponding to the circulation {circulation (equivalent)}, the hydrodynamically speaking circulation is obtained by integrating the product of the tangential direction and the line segment of each point along the closed curve in the flow. In the case of the form, since the propeller refers to a broad meaning including a cyclically obtained by using a vector of a flow along a rotating circumference, it is expressed as 'circulation = value corresponding to circulation' in the present description. Moreover, in deriving the point which becomes the maximum of circulation, the means can also be devised while considering the cost-effectiveness.

In addition, depending on the propeller shape, the position of the peak at which the propulsion force is maximized may be different, so that the circumference of the integral may be displaced from the position of 70 to 80% of the reflux distribution, thereby preventing the study to obtain a valid result. It is not.

In the above description, the case where the propeller is also processed two-dimensionally by using a vector on the propeller surface (whole surface) is described. However, the three-dimensional method is used to obtain an offset, or the three-dimensional offset and the propeller. The position may be obtained. In this case, in the above, the graph plot unit obtains a circulation (equivalent value) determined by the coordinates (x, y) of the center of the maximum thrust circle R at each point on the Z axis, and calculates a value on the Z axis in the xyz space. You can plot it.

In this case, the 'plot the value on the Z axis in the xyz space' is a visual representation of a significant value determined by one meaning at the coordinate (x, y) of the center of the maximum thrust circle R. For example, as a graph, using a plurality of graphs remaining in the two-dimensional manner using the xy plane does not prevent various designs such that the height of the value in each graph is represented by the color or the contour. As long as you can see and recognize the value and the height of the significant value, it does not matter.

In the case where there is a significant peak near the origin, it has the (x, y) coordinates of the point and serves as the central axis of the propeller's rotation axis. If it is inconspicuous, the coordinate (x, y) of the propeller's axis of rotation will change from the center axis of the skeg to more than the radius of propeller rotation, and the maximum propulsion circle R center coordinate control will be changed in sequence. The plot section plots the corresponding value, which is the result of each calculation.

Rotational flow is naturally generated near the center axis of the skeg, and rotational flow does not occur originally at a place far enough from the center axis, and there is a significant value even if the center of the rotational axis of the propeller is changed there. The value of does not change. Therefore, if there is a significant peak, it is not located so far from the center axis of the skeg, and even if it is farthest, it can be considered as the range of the radius of the propeller from the center axis of the skeg.

In this way, the central axis of rotation of the propeller, in which the propulsion performance of the vessel is almost maximum in the skew shape and the size of the propeller, is determined.

The propulsion performance is almost maximum. Depending on the shape of the ship, for example, even if pod propulsion is used, there is a possibility that the rotational axis of the propeller cannot be set at the optimum position due to physical constraints. It means setting in the vicinity of the coordinate of the optimal rotation axis calculated by. The purpose of the present invention is to improve the propulsion performance by the positional relationship between the skeg shape and the propeller, and is not limited to maximizing the propulsion performance to the strictest in the practice of the present invention. , In accordance with the spirit of the present application.

On the other hand, the above is an example of a method using software in order to find the optimum position of the propeller's rotational axis to the last, for example, by making the water flow from the front in a predetermined skeg shape, the environment as in the case of propulsion of the ship It is also possible to use a method of obtaining a rotation axis of the propeller that is the maximum propulsion force by using the actual value obtained from the experiment, such as making it and operating the pod propeller from the rear to measure the force obtained by the pod propeller.

Fig. 11 and Fig. 12 show three-dimensional display of the contours of the graph- plotted circulation and the contours of the graph plotting the coordinates of the central axis of the propeller's rotation determined uniquely by the shape of the ship's skeg and the radius and shape of the propeller. It is a schematic diagram showing. The approximate circulation (equivalent value) derived in the series of steps described above is plotted. FIG. 11 is a view of the graph from the Z axis, and FIG. 12 is an overhead view of the graph.

This approximate circulation can be determined based on where the rotation axis of the propeller is installed and the magnitude of the radius of rotation of the propeller, provided that the vector of the rotational flow occurring behind the skeg is defined on the plane. The axis of rotation (x, y) of the propeller that maximizes this approximate circulation is the point that maximizes the return gain in the propeller, and is approximately optimal in the skeg shape and the size (rotation radius) of the propeller. It is thought to be the position of the rotation axis.

Next, the operation | movement and operation | movement of the said embodiment comprised as mentioned above, and the increase effect of the propulsion force acquired at the time of the said ship moving forward are demonstrated.

As shown in FIG. 5, the vessel is provided with two sets of skags and a pod propeller. As shown in FIG. 4, the skeg has a twisted shape. The pod propeller has a clockwise rotation on the left side as shown in FIG. 5 and a counterclockwise rotation on the right side, each having an offset of the form shown in FIG. 10 toward the central axis side of the hull. It is installed.

When the vessel starts moving forward, flow begins to develop behind the stern and the skeg. From the left and right skegs in the center of the hull, a flow is directed toward the left and right directions, respectively, but as described above, since the skeg is twisted, the left and right skegs As for that, a rotational flow is generated on the left side and is stronger than the flow generated on the opposite side. That is, stronger rotational flow is generated on the side of the central axis of the ship.

In order to capture this rotational flow as a counter flow, a pod propeller is provided with an offset toward the center axis direction of the hull. This allows the propeller to capture more of the rotational flow caused by the torsional skeg as offset counterflow, so positioning of the pod propeller with the most common skeg shape and shaft center is achieved. Compared to the ship, the propulsion is increased significantly.

Therefore, according to the fourth embodiment, the position of the rotating shaft of the propeller that maximizes the return flow gain in the deformed skeg shape for amplifying the rotational flow and the combination of the skeg shape and the propeller can be obtained. Since the propeller can be installed at the optimum rotational shaft position of the pod propeller and the main engine direct propeller, it contributes to the improvement of the propulsion efficiency of various vessels and the reduction of fuel economy.

In addition, by using a two-axis stern catamaran type ship, the skeg provided for the stability of the hull becomes small enough, and the adverse influence on the return as an obstacle in front of the propeller is reduced, and the center of the drive shaft is the center of the skeg. By having a propeller offset from the shaft, it is possible to make the propeller's rotation direction and the reverse flow stronger in the rear of the skeg by using a unique upstream of a two-axis stern catamaran type vessel, and increase the return gain. . That is, by offset, the vector component of the flow which acts effectively with respect to a propeller with respect to a propeller can be made large behind a skeg, and the ship which is suitable from the viewpoint of energy saving which improved propulsion efficiency is provided.

In addition, there is no structure passing through the propulsion shaft of the single-axis propulsion ship or the two-axis propulsion ship in the front of the propeller by the skew positioned with the offset and the pod propeller driving the propeller to propel the ship. It is possible to reduce the adverse effect on the backflow as an obstacle in front of the propeller, to eliminate the water flow that adversely affects the propeller propulsion efficiency, and also to make the flow behind the skeg optimally act as a counter flow to the propeller. As a result, the driving efficiency can be further improved.

Furthermore, after obtaining the flow vector data, the input of the propeller radius and the drawing of the maximum propulsion circle, the central coordinate value of the maximum propulsion circle R, the continuous fluctuation and the derivation of the flow vector on the maximum propulsion circle R, and the total circumference over the maximum propulsion circle of the flow vector value As a result, a series of processing algorithms can be algorithmized, such as the loading of the minute, the drawing of the contour line by the graph plot from the loading minute result, the optimal position classification of the maximum point of the contour line, and as a result, in the combination of the skeg shape and the propeller The design method of the stern shape which automated the calculation process of the optimum position of propeller installation which enlarges the counter flow which a propeller receives is realizable.

Existing ships using Ford thrusters with mechanical drives can increase propulsion efficiency by making simple modifications to offset the installation location, which is cost effective and resource saving.

In addition, due to differences in navigational areas such as salt areas such as polar ice floe areas and high and low seawater temperatures, the viscosity of seawater may rise or fall, or the amount of draft may change due to changes in draft due to loading. Assuming that it changes, by taking the structure that the offset position of a propeller can be changed suitably to an optimal place, it is thought that the improvement of propulsion efficiency and fuel economy can be aimed at further.

(Embodiment 5)

As described in Embodiments 1 to 4, the present invention improves the driving force by effectively utilizing the flow formed in the tunnel-shaped concave portion (tunnel portion) between the skgs. A biaxial stern catamaran vessel aims at obtaining maximum transport efficiency especially by the boundary layer suction apparatus provided in the tunnel part between skegs.

The space defined by the skeg and the bottom of a two-axis stern catamaran ship is called the tunnel part, but the inclination angle of the outer surface of the tunnel part in the horizontal direction is greatly related to the hull resistance and propulsion performance. When the inclination angle of the outer surface exceeds about 15 degrees, the resistance of the hull increases, and at 20 degrees or more, the increase in resistance due to peeling of the boundary layer becomes remarkable. In addition, since the fast flow of water (rising flow) generated in the tunnel part is transported out of the upper part of the tunnel part to near the surface of the water, the fast flow of water is recovered by the propeller, that is, it can be used as a counter flow of the propeller. none.

Therefore, by providing a boundary layer suction port in the tunnel portion and sucking water in the boundary layer, peeling of the boundary layer is prevented and an increase in resistance is suppressed. In addition, the direction and the rotational direction of the propeller are studied, and it is assumed that the propeller can be effectively recovered by using a high speed flow of water generated in the tunnel portion. In addition, by discharging the water in the boundary layer sucked from two places, it is possible to use as a steering at sea.

EMBODIMENT OF THE INVENTION Hereinafter, this embodiment is described with reference to drawings. In addition, below, the range required for description for achieving the objective of this invention is shown typically, The range required for description of the said part of this invention is mainly described, and the place which abbreviate | omits description is based on well-known technique. Shall be.

First, the problem of the conventional two-axis stern catamaran vessel is demonstrated. It is sectional drawing which shows typically the state which cut | disconnected the vicinity of the stern part of the conventional two-axis stern catamaran vessel in the front-back direction in the vicinity of the center. As shown in the figure, in a two-axis stern catamaran vessel, the bottom 520 of the hull 501 surrounding the tunnel-shaped recess 514 is inclined rapidly to rise toward the stern 513. . For this reason, confusion arises in the flow of the water in the ship bottom 520, and since resistance increases, it becomes disadvantageous in propulsion performance.

In particular, the resistance starts to increase from the degree of the inclination angle X of 15 degrees to the horizontal direction of the ship bottom 520 shown in FIG. 20, and when the inclination angle X becomes 20 degrees or more, the increase of resistance by peeling of a boundary layer becomes remarkable. . As shown by the thick dashed line in FIG. 20, the flow of water near the bottom 520 is a flow in the opposite direction to the flow of water in a region farther from the bottom 520.

FIG. 13: is sectional drawing which shows typically the state which cut | disconnected the stern part vicinity of the stern part of the biaxial stern twin type ship of Embodiment 5 of this invention in the front-back direction near the center, FIG. 14 is embodiment of this invention. It is a schematic diagram which shows the outline of the structure which looked at the 2-axis stern catamaran vessel which concerns on 5. As shown in the figure, a pair of scoops 11 and 12 are installed at the stern portion 13 of the hull 1, respectively, and a pair of pod propellers 210 are disposed just behind them. Ford propeller 220 is provided. The pair of pod propellers 210 and pod propellers 220 are provided with propellers 2101 and propellers 2201, respectively, and generate a propulsion force by the rotation of the propellers. In addition, the driving force is also caused by the discharge of the water from the discharge port 71 described later.

And when the biaxial stern catamaran vessel of Embodiment 5 of this invention propels, it is the vicinity of the stern part 13 which is enclosed by the skeg 11, the skeg 12, and the ship bottom 20 of the hull 1. In the tunnel-shaped recess 14, a strong upward flow F occurs in the direction of the stern portion 13 (the front direction in FIG. 14) indicated by the broken-line arrow in FIG.

Although FIG. 13 shows the state cut along the C1-C2 axis | shaft of FIG. 14, as shown in the said figure, the biaxial stern-biaxial type ship of Embodiment 5 of this invention is the boundary layer suction opening 70 and the discharge opening. 71, a path 72, an impeller (suction means) 73 and a motor (suction means) 74 are provided. As the impeller 73 provided in the path 72 is rotated by the motor 74, a flow of water from the boundary layer suction port 70 to the discharge port 71 is formed, and the water in the boundary layer is routed from the boundary layer suction port 70. It can suck in 72 and it can discharge backward from the discharge port 71. FIG. Moreover, the inclination angle X which the outer surface of the tunnel-shaped recessed part 14 makes with respect to a horizontal direction is set to 15 degrees or more.

The boundary layer suction port 70 is provided near the entrance of the tunnel-shaped recess 14. For this reason, in the vicinity of the entrance (A1 in the figure) of the tunnel-shaped recess 14, the water in the boundary layer whose flow closer to the bottom 20 is delayed by the viscosity of the water can be removed. As a result, in the tunnel-shaped recess 14, along the inclination angle X of the ship bottom 20, the water flow (A2, A3 in drawing) with high uniformity in speed can be formed. Thereby, peeling of the boundary layer in the tunnel-shaped recessed part 14 can be prevented and increase of resistance can be suppressed. As a result, the inclination angle X of the ship bottom 20 in the tunnel-shaped recessed part 14 can be made into 15 degrees or more, and since the volume of a stern part can be enlarged, it is a biaxial shaft with large loading capacity and high transport efficiency. A stern double vessel can be realized. Further, by discharging water backward from the discharge port 71 provided in the stern portion 13, the propulsion force of the two-axis stern twin-type vessel can be improved.

On the other hand, the boundary layer suction port 70 is preferably provided near the inlet of the tunnel-shaped recess 14 as in the present embodiment, but it is not necessary to necessarily be provided in this part. Since the boundary layer suction port 70 may complete the function of removing the water of the boundary layer, the boundary layer suction port 70 may be provided on the bow side or the stern side rather than the entrance of the tunnel-shaped recess 14. In addition, the boundary layer suction opening 70 may be provided in a plurality of sections or may be provided in a plurality of stages.

FIG. 15: is a schematic diagram which shows the outline of the state which looked at the tunnel-shaped recessed part 14 of the biaxial stern catamaran ship of 5th Embodiment from the ship bottom 20 side. In the figure, the left side is the bow side, the right side is the stern side, the upper side is the port side, the lower side is the starboard side, and the closest side is the downward side and the innermost side is the upper side. to be. As shown in the figure, the boundary layer suction port 70 is formed at the entrance of the tunnel-shaped recess 14 with the same width as the width dimension of the tunnel-shaped recess 14. Thereby, since the boundary layer of the whole width direction can be sucked in in the entrance of the tunnel-shaped recessed part 14, the increase of resistance can be suppressed effectively.

In addition, the water drawn in from the boundary layer suction port 70 is supplied to the stern portion 13 of the hull 1 (see FIG. 14) by an impeller 73 and a motor 74 provided in the path 72 indicated by the broken line. The driving force can be improved by discharging backward from the discharge port 71 provided.

As described above, the biaxial stern catamaran vessel of the fifth embodiment sucks water from the boundary layer from the boundary layer suction port 70 provided in the tunnel-shaped recess 14 to the tunnel-shaped recess 14. Therefore, peeling of a boundary layer can be suppressed and an increase in resistance can be suppressed. As a result, the inclination angle X of the bottom 20 in the tunnel-shaped recess 14 can be set to 15 degrees or more, so that a two-axis stern catamaran type vessel having a large loading capacity and high transportation efficiency can be realized.

In addition, when the angle of the inclination angle is set to 15 degrees or more, the flow of water in the tunnel portion is easily decelerated unless the suction means and the boundary layer suction port are provided. However, by sucking the boundary layer at the boundary layer suction port, it is possible to control the flow of water in the tunnel portion to obtain a water flow suitable for use as a counter flow to the propeller. Thus, when the angle of inclination angle is 15 degrees or more, the propulsion force of the two-axis stern catamaran type ship can be improved by using the flow of the tunnel part which was not available conventionally.

Embodiment 6

As described in the fifth embodiment, the biaxial stern catamaran vessel of the present invention discharges the water of the boundary layer sucked from the boundary layer suction port from the discharge port, thereby reducing the resistance and improving the driving force and the transport efficiency. In the following, the discharge port is set to two, and by changing the amount of water discharged from the two discharge ports, the rotational moment is applied to the hull to replace the micro steering during sailing. Explain. In addition, about the member demonstrated in Embodiment 1, description is abbreviate | omitted in this Embodiment.

FIG. 16: is a schematic diagram which shows the outline of the state which looked at the tunnel-shaped recessed part 14 of the biaxial stern catamaran ship of 6th Embodiment from the ship bottom 20 side. The relationship between right, left, up, down, front, and inside is the same as that described with reference to FIG. 15. As shown in the figure, the two-axis stern catamaran vessel of the present embodiment is provided with one discharge port in each of the stern on the right side and the stern on the left side of the stern portion 13 side from the central portion. It is a structure, and the discharge port 71A and the discharge port 71B are provided in the stern part 13 specifically ,. And in the vicinity of the discharge port 71A and the discharge port 71B of the path | route 72, the impeller 73A and the impeller 73B are provided, and rotation is changed by the motor 74A and the motor 74B, The amount of water discharged from the discharge port 71A and the discharge port 71B can be varied, respectively. Thus, two suction means, the motor 74A, the impeller 73A, the motor 74B, and the impeller (2) are provided in the path 72 from the boundary layer suction port 70 to the discharge port 71A and the discharge port 71B. By controlling 73B, the discharge amount of the water from the discharge port 71A and the discharge port 71B can be changed. In other words, by setting the discharge amounts of the two to be different, it is possible to give a rotation moment to the biaxial stern catamaran type ship to replace the micro steering during sailing. As a result, it is not necessary to steer the Ford propeller, and the problem of cavitation and noise resulting therefrom can be suppressed. In particular, by controlling the two impellers 73A and the impeller 73B and changing the amount of water discharged from the two discharge ports 71A and the discharge port 71B, for example, the rotational speed is lowered to discharge the water. In the lower side, the suction amount at the boundary layer suction port 70 also decreases, so that the discharge amount is weakened and the shipbuilding effect can be enhanced.

On the other hand, the discharge port 71A and the discharge port 71B are for shipbuilding by providing a rotation moment to the biaxial stern catamaran type ship and replacing it with the micro steering in voyage. For this reason, 71 A of discharge ports and 71 B do not necessarily need to be installed in the position which discharges water from the stern part 13 back. However, if it is set as the structure provided in the stern part 13, the propulsion force of a two-axis stern twin type vessel can be improved.

For example, the discharge to the rear of the water sucked from the boundary layer suction port 70 may be configured to be discharged from the stern portion 13 to the rear, but may be performed from the ship side, the ship bottom or the like. However, in order to improve the propulsion performance of the ship, the vessel is prevented by removing the boundary layer from the tunnel-shaped recess 14 to reduce the resistance, and by discharging the water sucked back to reduce the resistance. It is preferable that the direction (vector) for discharging water is toward the rear of the ship so as to achieve all of the driving functions.

On the other hand, the effect of imparting a rotation moment to the hull becomes large when discharging water in the direction immediately to the traveling direction. Usually, the shipbuilding state in which water is discharged to the side is extremely slow and the separation of the boundary layer is not a problem. However, when the water sucked in order to prevent the separation of the boundary layer is used for shipbuilding at low speed, It is also possible to employ a configuration in which water is discharged to the side.

As described above, the position, the number of the discharge ports, and the discharge direction of the water may be appropriately set in consideration of the effect of improving the driving force and the effect of applying the rotation moment.

Although the structure for changing the quantity of water discharged is not specifically limited, As a structure other than what was mentioned above, the structure shown in FIG. 17 is mentioned, for example. The said figure is a schematic diagram which shows the outline of the state which looked at the tunnel shape recessed part 14 of the biaxial stern catamaran vessel of this Embodiment 6 from the ship bottom 20 side. In addition, the relationship of right, left, up, down, front, and inside is as having demonstrated in FIG. In the structure shown in the figure, the movable portion 75, the sheet 75A, and the sheet 75B of the vane shape (guide blade shape) for changing the flow of water formed by the rotation of the impeller 73 are in the path 72. Of the water in the path 72 formed by the impeller 73 and the motor 74 by controlling the movable portion 75 provided in the path 72 from the boundary layer suction port 70 to the discharge port 71. It is set as the structure which changes a flow. As shown by the dashed-dotted line in the figure, by changing the direction of the movable portion 75, the flow of water from the two divided paths 72A to the discharge port 71A, and the discharge port from the path 72B ( By controlling the flow of water to 71B, the discharge amount of the water from the discharge port 71A and the discharge port 71B can be changed. Specifically, by changing the direction of the surface of the movable portion 75 with respect to the flow of the path 72, the amount of water flowing through the path 72A and the path 72B is changed, and the ratio of the amount of water discharged is changed. Can change. In addition, the path 72A can be closed by engaging the rotatable end of the movable portion 75 with the seat 75A, and the path 72B can be closed by engaging the seat 75B. have.

On the other hand, as a configuration for changing the flow of water in the path 72, as shown in Fig. 17, any path among the paths 72A and 72B branched in two directions from the middle can be blocked or the path width thereof can be narrowed. The valve which can block | close a path width or its width | variety and narrowness in each of path | routes 72A and 72B other than the moving part 75 is comprised by the plate-shaped body whose one end was pivotally supported so that the other end can rotate, You can see that installed. Controlling these movable parts 75 and providing valves in each of the paths 72A and 72B control the amount of water discharged even when there is only one impeller 73 or motor 74, so that two-axis stern twins are used. Has the advantage of ship type ship.

As described above, the biaxial stern catamaran vessel of the present embodiment includes two discharge ports, one for each of the left and right sides of the stern, and can be shipped by changing the amount of water discharged from these two discharge ports. It can be.

In the present embodiment, however, the discharge port 71A and the discharge port 71B are provided in the stern portion 13 toward the rear side. However, in addition to this configuration, a plurality of discharge ports may be provided on the ship side. For example, four discharge ports in total, two at the stern and two at the ship side, can be provided. In this case, (1) both of the stern and two of the ship side are discharged in the state of rearward while (2) navigating, and (2) at the time of the orientation change during navigation, two of the stern or the stern according to the situation The discharge amount is changed by combining two of them and two at the ship side, and (3) at low speed, such as at the time of entry, the discharge is discharged from the discharge port by stopping two of the sterns, changing the two directions on the ship side, and controlling the discharge amount. Various modifications can be considered in the method of controlling the discharge amount of water used.

(Embodiment 7)

As described in the fifth embodiment, the biaxial stern catamaran vessel of the present invention prevents the boundary layer from peeling off in the tunnel-shaped recess 14 by sucking the boundary layer at the boundary layer suction port 70. By providing the boundary layer suction port 70, an effect of making the upward flow F (see FIG. 14), which is a fast-flowing flow in the tunnel-shaped recess 14, suitable for use in improving the driving force, is also achieved. . Therefore, below, the embodiment which devises the rotational direction and the position of a propeller, and improves propulsion force using this upward flow F is demonstrated. In addition, description is abbreviate | omitted in this embodiment about the member demonstrated in Embodiment 1 or 2.

FIG. 18: is a schematic diagram which shows the outline of the structure which looked at the 2-axis stern twin type ship of Embodiment 7 of this invention from the rear. As shown in the figure, a pair of scoops 11 and 12 are installed at the stern portion 13 of the hull 1, respectively, and a pair of pod propellers 210 are disposed just behind them. Ford propeller 220 is provided.

The gap between the shaft center line 2101A of the propeller 2101 and the center shaft 11A of the skeg 11 at offset 2A, respectively, and the shaft center line 2201A of the propeller 2201 and the skeg ( The gap with the center axis | shaft 12A of 12 is respectively represented by the offset 2B.

As shown by the arrow in FIG. 18, the propeller 2101 of the pod propeller 210 and the propeller 2201 of the pod propeller 220 turn in the opposite direction. More specifically, the pod propeller 2101 is rotated clockwise when viewed from the rear, and the propeller 2201 is rotated counterclockwise when viewed from the rear, and is rotated so-called inwardly. For this reason, the pod thruster 210 can use the upward flow F as a counter flow in the area | region R1 of the right half of the rotating surface of the propeller 2101 shown by the circle | round | yen using a dashed-dotted line in the figure. Similarly, the pod thruster 220 can use the upward flow F as a counter flow in the area L2 of the left half of the rotation surface of the propeller 2201 shown by the circle | round-dotted line in the figure. On the other hand, the counter flow refers to the flow of water in a direction opposite to the rotation direction of the propeller. By using this counter flow, the loss caused by the propeller rotating water can be reduced, and the propulsion force can be improved.

In order to offset the pod thruster 210 and the pod thruster 220 from the center axis of the skeg 11 and the skeg 12 and reach a predetermined position, a connection part for connecting the pod thruster 210 with the bottom 20 is required. Do. Providing this connecting portion in the longitudinal direction causes a large frictional resistance by being exposed to the upward flow F in the tunnel-shaped recess 14, thereby reducing the propulsion efficiency.

Therefore, as shown in FIG. 18, in the two-axis stern catamaran vessel of the present embodiment, the pod propeller 210 and the pod propeller 220 are moved in the horizontal direction of the skeg 11 and the skeg 12. By connecting, the surface area of a connection part is made small and the frictional resistance by the exposure of the connection part to the upward flow F is realized.

That is, the pod propeller 210 has the skeg 11 across the pod strut (connection part) 21 provided in the inner side of the skeg 11 (a side which becomes the right side of the skeg 11 when viewed from the rear). ), And the pod propeller 220 has a pod strut (connecting portion) 22 provided inside the skeg 12 (side that becomes the left side of the skeg 12 when viewed from the rear). It is connected to the skeg 12. The position at which the pod propeller 210 has an offset and faces it is closer to the skeg 11 than the ship bottom 20 normally. For this reason, by connecting the pod propeller 210 inside the skeg 11, the pod strut 21 can be made small compared with the case where the pod propeller 210 is connected to the ship bottom in the vertical direction. That is, by connecting the pod strut 21 in the transverse direction of the skeg 11, the surface area can be set extremely small as a result. In addition, the flow of the upward flow F is slower between the pod propeller 210 and the skeg 11 than between the pod propeller 210 and the bottom 20. The same applies to the pod strut 22 which connects the other pod thruster 220 to the inside of the skeg 12.

Therefore, by installing the pod struts 21 and the pod struts 22 in the transverse directions of the skegs 11 and 12, the surface area is made extremely small and it is possible to arrange the portion where the flow is slow. Can be. Thereby, the pod strut 21 and the pod strut 22 which connect the offset pod thruster 210 and the pod thruster 220 to the hull 1 are due to exposure to the upward flow F. The resistance can be made small.

Moreover, most of the area | region L1 of the left half of the rotating surface of the propeller 2101 is located in the area | region where the flow of water of the back of the skeg 11 and the pod strut 21 is late. In addition, most of the region R2 of the right half of the rotating surface of the propeller 2201 is similarly located in the region where the water flow is late. For this reason, in the area | region where the upward flow F cannot be used as a counter flow, it is hardly influenced by the offset. Therefore, by offsetting the shaft center line 2101A of the propeller 2101 from the center axis of the skeg 11, it is hardly adversely affected by the upward flow F. As shown in FIG. The same applies to the propeller 2201.

Therefore, since the upward flow F can be used as a counter flow by offsetting the propellers 2101 and the propellers 2201, the driving force is greatly improved.

Thereby, since the upward flow F resulting from the inclination of the bottom 20 near the stern part 13 can be used for the improvement of propulsion force, the inclination of the bottom 20 can be enlarged. Therefore, the starting point of the inclination of the ship bottom 20 in the vicinity of the stern part 13 can be moved to the rear rather than before, and the load amount of a biaxial stern twin boat type can be enlarged.

As described above, the biaxial stern catamaran vessel of the seventh embodiment offsets the propeller 2101 and the propeller 2201 from the center shafts of the skeg 11 and the skeg 12 to improve the propulsion efficiency. It is an improvement. Moreover, since the pod strut 21 and the pod strut 22 are provided in the transverse direction of the skeg 11 and the skeg 12, they minimize the frictional resistance by exposing them to the upward flow F. You can do

Embodiment 8

The two-axis stern catamaran vessel of the present invention can be implemented as having two propulsion means provided with a propeller, as in the two-axis stern catamaran vessel described in Embodiments 1 to 3 and 5 to 7, It can also be implemented by having more. However, the propulsion force of a two-axis stern catamaran vessel equipped with three or more propulsion means is mainly obtained by two propulsion means in which a part of the rotating surface of the propeller is arranged between the skegs. In the present embodiment, a two-axis stern twin vessel equipped with four pod propellers will be described.

FIG. 19: is a schematic diagram which shows the outline of the structure which looked at the biaxial stern double catamaran ship which concerns on Embodiment 8 of this invention. As shown in the figure, in the stern portion 13 of the hull 1, the two-axis stern catamaran type ship of the eighth embodiment is located just behind the pair of skegs 11 and 12. In addition to the pod propellers 210 and the pod propellers 220 respectively provided on the inside, the pod propellers 230 and pod propellers 240 are provided on the outer side immediately behind the skegs 11 and 12. Is provided. Among the other configurations provided by the two-axis stern catamaran vessel of the eighth embodiment, those described in the above-described embodiments are denoted by the same numerals and description thereof is omitted.

The pod propeller 230 is connected to the outside of the skeg 11 by the pod strut (connection part) 23. Thus, although the pod propeller 230 is connected to the skeg 11 similarly to the pod propeller 210, when viewed from the stern side of a two-axis stern twin-type ship, the center shaft of the skeg 11 ( The offset from 11A) is reversed. For this reason, when the two-axis stern twin vessel moves forward, the pod propeller 230 rotates the propeller 2301 in the direction opposite to the pod propeller 210, as indicated by the thick solid arrow in the figure. Thereby, the water flow outside the skeg 11 shown by the arrow with a thick broken line in the said figure can be used as a counter flow.

The pod propeller 240 is connected to the outside of the skeg 12 by a pod strut (connection part) 24. As described above, the pod propeller 240 is connected to the skeg 12 similarly to the pod propeller 220, but when viewed from the stern side of the two-axis stern twin-type vessel, the center shaft of the skeg 12 ( The offset from 12A) is reversed. Therefore, when the biaxial stern twin vessel moves forward, the pod propeller 240 rotates the propeller 2401 in the direction opposite to the pod propeller 220, as indicated by the arrows in the figure. Since the water flow outside the skeg 12 shown by the thick broken line arrow in the figure can be used as a counter flow, the propulsion force of the two-axis stern double catamaran vessel can be improved.

As described above, the biaxial stern catamaran vessel of the present embodiment further improves the driving force by the pod propeller 230 and the pod propeller 240 provided in addition to the pod propeller 210 and the pod propeller 220. At the same time, the straightness can be improved.

In addition, by providing the pod propeller 230 and the pod propeller 240 outside the skeg 11 and the skeg 12, it becomes easy to change directions, for example, at the time of port entry.

In addition, this invention is not limited to each embodiment mentioned above, It is possible to change variously and to implement in the range which does not deviate from the main meaning of this invention. In addition, this invention can also be implemented as what combined said structure demonstrated as embodiment.

For example, the propeller offset position can be appropriately changed to an optimal location by changing the propeller offset position in units of a single navigation schedule or by other means, for example, seawater. Means to measure in real time information such as temperature, viscosity, and draft, such as the depth of the ship immersed in water, and automatically change the optimum offset position of the propeller at any time. It may be in the form of adjusting the system.

In addition, embodiment mentioned above is only what was shown to the example for implement | achieving the technical thought concerning this invention, and it is possible to apply the technical thought concerning this invention in other embodiment.

[Industry availability]

Therefore, the present invention can be used for small vessels, including large vessels, and in addition to the general maritime industry including shipbuilding and marine industries, as well as the whole of society in terms of environment such as prevention of global warming. It brings great benefits.

1: hull
2A, 2B, 3A, 3B: Offset
11, 12, 51, 52: Skag
11A, 12A, 51A, 52A: Center Shaft
21, 22, 23, 24: pod struts
210, 220, 230, 240: Ford Propeller
2101, 2201, 3101, 3201: propeller
2101A, 2201A, 3101A, 3201A: Propeller Shaft
310, 320: main engine direct propeller
3202: drive shaft
3203: main engine
61, 62: protrusions
70: boundary layer inlet
7171A, 71B: Outlet
72, 72A, 72B: route
73, 73A, 73B: impeller (suction means)
74, 74A, 74B: Motor (suction means)
75: movable part

Claims (16)

In a two-axis stern twin vessel equipped with two propellers, a propulsion means for driving the two propellers to propel the two-axis stern twin vessel, and two installed on the hull of the two-axis stern twin vessel A two-axis stern twin vessel provided with a skeg, the center of which drive shafts of the two propellers are offset from the center shaft of the two skegs, respectively. 2. The two-axis stern twin vessel according to claim 1, wherein the direction of each of the offsets is changed by the directions of rotation of the two propellers. The method of claim 1 or 2, wherein the width of the offset is determined in accordance with the point that the maximum of the circumference of the circle around the circle drawn with a radius of 70 to 80% of the return distribution on the propeller surface is determined. 2-axis stern catamaran vessel. The propeller located on the left side of the propeller on the left side is rotated on the right side according to the rotation direction of the propeller driven in two axes. A two-axis stern catamaran vessel, characterized in that the propeller is located in the counterclockwise rotation. The two-axis stern catamaran vessel according to claim 1 or 2, wherein the rear portion of the skg is twisted in a direction opposite to the rotational direction of the propeller. The two-axis stern twin vessel according to claim 1, wherein the propulsion means comprises two pod propellers. The two-axis stern catamaran vessel according to claim 6, further comprising a connecting portion for connecting the pod propeller in the transverse direction of the skeg. The two-axis stern twin vessel according to claim 6 or 7, wherein the pod propeller is electrically driven. The propulsion means according to claim 1 or 2, wherein the propulsion means is a main engine for driving the two propellers, and the skeg has a protruding portion for receiving the drive shaft of the propeller in the transverse direction of the skeg. A two-axis stern twin vessel. In a two-axis stern twin vessel with two skags on the stern and two propellers driven in two axes,
A two-axis comprising a boundary layer suction port provided in the tunnel portion formed between the two skgs, suction means for sucking water from the boundary layer suction port, and a discharge hole for discharging water sucked by the suction means; Stern catamaran vessel. The two-axis stern catamaran vessel according to claim 10, wherein the boundary layer suction port is provided near an inlet portion of the tunnel portion. 12. The two-axis stern twin vessel according to claim 10 or 11, wherein the width dimension of the boundary layer suction port is set to an approximate width dimension of the tunnel portion. The two-axis stern catamaran type ship according to claim 10 or 11, wherein an angle of the inclination angle of the outer surface of the tunnel portion with respect to the horizontal direction is 15 degrees or more. 12. The shipbuilding of the biaxial stern catamaran type ship according to claim 10 or 11, wherein at least two discharge ports are provided and the amount of water discharged from the two discharge ports is changed. A two-axis stern catamaran vessel, characterized in that. 15. The method of claim 14, wherein the two suction means are provided in a path from the boundary layer suction port to the discharge port, and the amount of water discharged from the two discharge ports is changed by controlling the two suction means. A two-axis stern twin vessel. 15. The apparatus according to claim 14, further comprising a movable part for changing the flow formed by the suction means in a path from the boundary layer suction port to the discharge port, and controlling the movable part to change the amount of water discharged from the two discharge ports. A two-axis stern catamaran vessel, characterized in that.

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