JP4421495B2 - High speed catamaran - Google Patents

Description

  The present invention improves the propulsion performance and seaworthiness performance of a high-speed catamaran with a transom surface at the stern and a design maximum speed of 0.35 to 1.5 in terms of fluid number compared to a conventional catamaran. It relates to a high-speed catamaran, especially to the stern hull shape.

  As a high-speed ship, a catamaran that can use a deck having a large area as shown in FIG. 7 is often used, and much efforts have been made to improve the propulsion performance and the seaworthiness performance.

  One of these is the relationship between the ship length L, the full width b of the waterline surface, and the full width B of the waterline surface of the catamaran on one side of the catamaran 15 ≦ L / b ≦ 30, 3 ≦ B / b ≦ 5. As the ship length L becomes longer, the hull resistance during high-speed sailing can be reduced, and the length of the ship will be long enough to improve the seaworthiness and reduce the shaking. A catamaran has been proposed in which the space between the catamaran is narrowed to reduce the weight of the catamaran coupling portion to reduce the required strength and enable an increase in size (for example, see Patent Document 1).

  In addition, for the purpose of reducing wave resistance, the distance from the center line of each hull of the catamaran to the inner surface from the hull center is made shorter than the distance from the center line to the outer surface from the hull outside. Therefore, the sea level gap between the two trunks is widened to slow down the flow velocity at this part, and the high velocity twins are set so that the flow velocity at the inner sea surface part between the trunk parts and the outer sea surface part outside the trunk part are almost equal. A ship hull shape has been proposed (see, for example, Patent Document 2).

  However, these catamarans have a problem of propulsion performance in flat water, and do not mention the fine shape of the hull form. Therefore, there is still room for improvement in the propulsion performance and seaworthiness performance of catamaran.

As shown in FIG. 6, in the conventional normal high-speed catamaran, the bow shape is formed without a bow valve, and the stern shape is formed with a transom surface at the stern. Further, the width of the ship in each cross section is formed so as to gradually increase from the ship bottom side toward the water surface. Maintaining such a hull shape makes it difficult to suppress hull swaying under normal sea conditions where the wave period is relatively short, even if it is intended to further improve the propulsion performance and seaworthiness performance during voyage. There is a problem that it is difficult to improve the propulsion performance and seaworthiness performance in the waves.
JP 05-345586 A JP 2000-344179 A

  The present invention has been made to solve the above-described problems, and its object is to provide a high-speed twin that can further improve the propulsion performance and seaworthiness performance in flat water and in waves compared to a conventional catamaran. It is to provide a boat.

  In order to achieve the above object, a high speed catamaran of the present invention has a transom surface at the stern and a maximum design speed of 0.35 to 1.5 in terms of fluid number. The height from the base line of the buoyancy position is 0.6 to 0.9 times the draft of the high-speed catamaran, and the stern side water line shape in the draft is the ship width at the water surface of the transom surface Is formed by narrowing the ship width on the water surface toward the stern so that it is narrower by 10% to 30% than the maximum width on the water surface in the stern direction. Is formed to be approximately the same as the width of the ship at the surface of the water, and the width of the ship is widened at the bottom of the ship so that the maximum width in the cross section is 10% to 30% wider than the width of the ship at the surface of the water. The

The Froude number Fn is a dimensionless value of the ship speed V, and is obtained by dividing the ship speed V by the square root of the product of the gravitational acceleration g and the water line length LWL (Fn = V / (g × LWL) ^{1 / 2} ). The draft here is a draft in the center of the hull.

  According to this configuration, the width of the ship on the water surface is narrowed toward the stern, and the transom surface is reduced, so that the transom resistance generated at the stern end is reduced. On the other hand, the bottom end of the transom, which is the stern end, is hardly squeezed and has a wide bottom, so the lift received by the bottom during high-speed navigation is hardly reduced compared to the conventional hull form, and the hull is lifted. And maintain a navigational attitude similar to that of a conventional hull form.

  As a result, the hull resistance decreases as the transom resistance decreases, and the propulsion performance in plain water improves. As for the sailing attitude, even if the stern-side levitation force is slightly reduced due to the hull form, the levitation force of the hull can be assisted by actively providing a lift generating device such as a trim tab. It will not be.

  In addition, since the width of the ship on the surface of the water is narrowed toward the stern, the area of the waterline becomes smaller, so the restoring force due to buoyancy in vertical movement and pitching is reduced, so the natural period of vertical shaking in waves Becomes longer. Therefore, under normal sea conditions with a short wave period, the wave period deviates from the natural period of the catamaran, so that resonance can be avoided and the hull motion is reduced.

  In addition, on the stern side, the hull width below the water surface is larger than the ship width near the water surface, so the damping force against vertical and vertical vibrations increases, and this also reduces the hull vibration. be able to. Therefore, from these two points, the hull swaying in the waves can be reduced, and the propulsion performance and seaworthiness performance in the waves can be improved.

  Further, the bow portion is formed with a bow valve. That is, a hull with a bulb having a bulbous volume in the cross-sectional shape below the water surface in front of the bow perpendicular (FP), that is hardly adopted in conventional high-speed catamarans. Shape.

  With this configuration, wave resistance in flat water is further reduced, and on the bow side, there is a bow valve under the waterline that has a great damping effect against vertical and vertical vibrations. Can be further suppressed, and the propulsion performance and seaworthiness performance in the waves can be improved.

  According to the high-speed catamaran of the present invention, the transom resistance can be reduced on the stern side, and the vertical and vertical swings can be reduced under normal sea conditions with a short wave period. Seaworthiness performance can be improved.

  Embodiments of a high-speed catamaran according to the present invention will be described below with reference to the drawings.

  As shown in FIGS. 1 to 5, the high-speed catamaran 1, 1 </ b> A of this embodiment is a high-speed Froude having a transom surface 11 at the stern of the trunk 10, 10 </ b> A having a Froude number Fn of 0.35 to 1.5. It is a catamaran.

  And the water surface W. L. 1, the width BWL (AP) of the transom surface 11 is 10% to 30% narrower than the maximum width BWLmax at the water surface near the center of the ship in the bow direction. In addition, the maximum width BWLmax is gradually narrowed toward the stern. That is, BWLmax × (1-0.3) ≦ BWL (A.P.) ≦ BWLmax × (1-0.1). The dotted line shows the conventional hull shape, and the solid line shows the hull shape of the present invention. The hull shape of the present invention has a narrower stern portion on the surface of the water than the conventional hull shape.

  2 and 4, at the stern end (A.P.) of the high-speed catamaran 1, 1A, the base line (baseline) B. of the floating position Bt on the transom surface 11 is shown. L. The height KBt (A.P.) Is set to 0.6 to 0.9 times the draft d of the high-speed catamaran 1, 1A. That is, d × 0.6 ≦ KBt (A.P.) ≦ d × 0.9. As the draft d, the draft at the center of the hull is used.

  As shown in FIGS. 2 and 4, on the transom surface, the ship width B (AP, Z) in the draft direction is widened below the draft d (AP), and the maximum width Bmax ( AP). This maximum width Bmax (A.P.) is formed so as to be 10% to 30% wider than the ship width BWL (A.P.) on the water surface of the cross section. That is, BWL (AP) × (1 + 0.1) ≦ Bmax (AP) ≦ BWL (AP) × (1 + 0.3) Note that FIGS. 2 and 3 are linear hulls, and FIGS. A curved hull.

  On the bow side, as shown in FIG. P. A so-called bow valve 12 having a volume with a bulbous cross section is formed below the front water surface. The bow valve 12 is formed to have an effect of reducing wave resistance, but can exert a large damping force against vertical and vertical swings.

  And by these structures, this water surface W.D. L. Since the stern width BWL (X) is narrowed toward the stern, the transom resistance at the stern end is reduced. This transom resistance is a hydrostatic resistance, and because the stern end is almost vertical, water does not turn to the stern side during high speed navigation, creating an air cavity, so the pressure on the stern side is low. Resistance.

  On the other hand, the floating height KBt (AP) of the transom surface 11 is set to 0.6 to 0.9 times the draft d (AP) on the transom surface 11 to be a high position, and the transom surface 11 which is the stern end. Since the lower end surface of the slab is hardly squeezed and is kept wide, the lift generated at the bottom of the ship at the time of high-speed navigation does not drop, and the hull can be lifted to maintain the navigation posture. Therefore, the hull resistance is reduced and the propulsion performance is improved. In addition, this levitation can be assisted by positively providing a lift generating device (not shown) such as a trim tab.

  In addition, the water surface W.V. L. The ship width BWL (X) is narrowed toward the stern to reduce the waterline area and L. Since the shape is maintained as it is immediately below, the restoring force due to buoyancy in vertical movement and pitching is reduced. Therefore, the natural period of ups and downs and pitches in the waves can be lengthened and shifted from the wave period under normal sea conditions where the wave period is short, and the hull motion can be reduced.

  Furthermore, on the transom surface, the water surface W.D. L. The ship width B (A.P., Z) on the bottom side of the bottom is the surface of the water. L. Since it is formed larger than the ship width BWL (A.P.), the damping force against vertical and vertical vibrations is increased, so that these hull fluctuations can be reduced. In addition, since the bow valve 12 is provided on the bow side to increase the damping force against vertical and vertical shaking, these hull fluctuations can be further reduced from this point. Therefore, it is possible to improve the propulsion performance and seaworthiness performance in the waves in a high-speed catamaran.

It is a figure which shows the water line surface shape in the water surface in the high-speed catamaran of embodiment which concerns on this invention. It is a figure which shows the cross section of the water surface maximum width of the high-speed catamaran of embodiment of the linear shape which concerns on this invention, and the cross section of a transom surface. It is a figure which shows the cross section by the side of the stern of the high-speed catamaran of embodiment of FIG. It is a figure which shows the cross section of the water surface maximum width of the curvilinear shape embodiment of this invention, and the cross section of a transom surface. It is a figure which shows the cross section by the side of the stern of the high-speed catamaran of embodiment of FIG. It is a perspective view of the bow side of the high-speed catamaran of the embodiment according to the present invention. It is a figure which shows the cross section of the hull shape of a conventional high-speed catamaran. It is a figure which shows the general form of a high-speed catamaran.

Explanation of symbols

1,1A, 1X High-speed catamaran 10,10A trunk
11 Transom surface 12 Bow valve

Claims (2)

In a high-speed catamaran with a transom surface at the stern and a design maximum speed of 0.35-1.5 in terms of fluid number,
The height from the base line of the floating position on the transom surface is 0.6 to 0.9 times the draft of the high-speed catamaran,
The stern line shape at the stern side of the draft is set so that the width of the transom surface on the water surface is 10% to 30% narrower than the maximum width on the water surface in the stern direction. Squeeze and form,
Furthermore, the cross-sectional shape at the transom surface is formed to be approximately the same as the ship width at the water surface near the draft, and the ship width is widened at the bottom of the ship so that the maximum width at the cross-section is the ship width at the water surface. A high-speed catamaran that is 10% to 30% wider than its width. The high-speed catamaran according to claim 1, further comprising a bow valve at a bow portion.

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