Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
  • B63B1/32—Other means for varying the inherent hydrodynamic characteristics of hulls
  • B63B1/40—Other means for varying the inherent hydrodynamic characteristics of hulls by diminishing wave resistance
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T70/00—Maritime or waterways transport
  • Y02T70/10—Measures concerning design or construction of watercraft hulls

Definitions

• the present invention proposes to reduce the disturbances of this kind of flow.
• the invention finds a particularly interesting application in the improvement of the hulls of fast sailboats in order to enable them to reach higher speeds under the action of the motive power exerted by the winds on the wing; it can also advantageously be applied to any other partially or totally submerged body comprising a shell and one or more protuberances.
• the invention proceeds from the results of resistance to advancement tests carried out on hulls composed of a hull proper and of one or more submerged protuberances constituted by a keel and its ballast, by a rudder or by d other devices.
• the hull proper is given a regular traditional longitudinal profile from the bow to the stern as defined up to
• the principle of the invention consists in delaying this damaging formation of the wake wave which is established at the level of the keel or more generally at the level of a protuberance on the transverse submerged profile.
• the profile of the hull is determined in such a way that the curve representing the variation, from the bow to the stern, of the total submerged cross-sectional area (hull + protuberances) shows no bump or sudden variations in curvature; in other words, in the cross sections affected by the protrusions, the sections of these protrusions are "erased” by compensating for them by reductions in the submerged sections which contain them.
• Test results carried out in the hull basin show that, for the same speed, the engine power can be reduced by more than 20% at a speed of 9 knots and reduced by more than 25% at a speed of 12 knots.
• the gains are therefore in a speed zone commonly reached by fast yachts.
• FIG. 1 illustrates, in perspective with cross section, the general principle of modification of a hull profile in the case where the protuberance is located in a predetermined position
• 2 shows, in side view, the longitudinal profile of a sailboat hull provided with a keel and a rudder with indication of the horizontal waterline
• Figure 3 is a graph showing the variation of the submerged cross section for a shell according to Figure 2
• FIGS. 4 to 6 are diagrams of wake waves for increasing speeds of this type of hull in water
• FIG. 7 is a graph illustrating the variation of the inclination of the wake wave as a function of the speed in knots for a hull according to FIG. 2
• FIG. 1 illustrates, in perspective with cross section, the general principle of modification of a hull profile in the case where the protuberance is located in a predetermined position
• 2 shows, in side view, the longitudinal profile of a sailboat hull provided with a keel and a rudder with indication of the horizontal waterline
• FIG. 8 represents a perspective view, with partial cutaway, of a hull of a keel boat with illustration of profile corrections
• Figure 9 is a graph similar to that of Figure 3, but established for the shell of Figure 8 corrected according to the invention
• Figures 10 and 11 show, in cross section, a sailboat with section corrections taking into account its sailing conditions. tion with lodging
• Figure 12 shows, in perspective, a half shape for molding a profiled polyester shell according to the invention.
• Figure 1 there is shown a partially submerged body, for example a boat moving in the direction of arrow A, cut in line with a protuberance perpendicular to the direction of fluid flow represented by arrows E.
• a reference section (as it results from the determination of the hydrodynamic profile carried out by means of tests recalled above) is delimited by the curve C partially drawn in dotted lines. If a protuberance P is created above the zone C1 of the curve C in the submerged part, this protuberance determines an increase in surface area Sp of the section.
• the idea of the invention consists in correcting in hollow the reference section C in two zones located on either side of the protuberance, surface zones S1 and S2 and limited by two curves P1 and P2 to the inside areas C2 and C3 of curve C.
• FIG. 2 the longitudinal profile of the hull proper, for example of a sailboat, has been indicated in 1, while the ballasted keel is indicated in 2 and the rudder in 3.
• the hull ensures the buoyancy of the whole while the keel, the ballast and the rudder ensure
• the solid line illustrates the section of the shell 10, as it has been corrected in reduction from the theoretical contour 11 always illustrated in this figure 8.
• the mixed line represents the corresponding overall section to the previous section (solid line) increased by section S "of the keel 12.
• FIG. 10 is a cross section which indicates that the reduction in cross section of the hull, according to the method described in support of FIG. 8, is extended beyond FF ′ (water line as in FIG. 8 ) to the smooth bb 'under the same conditions.
• Figure 11 is a cross section of the hull of the sailboat at maximum heel G. It indicates that the reduction in area S'G is equal to the reduction in area S 'in FIG. 10.
• the surfaces of the circular sectors Hf and H'f are equal.
• the surface Hf which is added to S 'and the surface H'f which is subtracted therefrom compensate each other and S' is equal to S'G.
• the liquid flow can remain continuous (laminar) despite the presence of this protuberance and thus the appearance of turbulence is delayed, which causes parasitic drag.

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• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
• Wind Motors (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9244808

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (2)

Citations (3)

• 1980
  • 1980-08-01 FR FR8017058A patent/FR2487774A1/fr not_active Withdrawn
• 1981
  • 1981-07-16 GR GR65526A patent/GR74633B/el unknown
  • 1981-07-31 IT IT23271/81A patent/IT1138484B/it active
  • 1981-08-03 JP JP56502523A patent/JPS57501474A/ja active Pending
  • 1981-08-03 WO PCT/FR1981/000095 patent/WO1982000447A1/fr not_active Ceased
  • 1981-08-03 GB GB8209046A patent/GB2092075B/en not_active Expired
• 1982
  • 1982-03-31 SE SE8202056A patent/SE434248B/sv unknown

Patent Citations (3)

Non-Patent Citations (1)

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