US3773006A

US3773006A - Hull construction

Info

Publication number: US3773006A
Application number: US00184711A
Authority: US
Inventors: R Black
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-09-29
Filing date: 1971-09-29
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20

Abstract

A hull construction in which displacement portions are carried to depend downwardly from the bottom surface of the hull and have a progressively increasing depth and width extending rearwardly along the bottom surface. The displacement portions terminate in a step. A planing surface is disposed adjacent the step to extend laterally across the bottom surface in a direction defined between the port and starboard chines of the hull and in spaced relation beneath the hull. The displacement portions and bottom surface serve to form flow passages commencing forwardly beneath the bottom surface, progressively diminishing in cross-section rearwardly beneath the hull, and terminating above the planing surface.

Description

[ Nov. 20, 1973 HULL CONSTRUCTION [76] Inventor: Robert B. Black, 1250 34th Ave.,-

San Francisco, Calif. 94121 [22] Filed: Sept. 29, 1971 [21] Appl. No.: 184,711

[52] US. Cl. l14/66.5 H, 1l4/66.5 S, 114/67 A [51] Int. Cl B63b l/20, B63b 1/38 [58] Field of Search 1l4/66.5 R, 66.5 H, 114/665 P, 66.5 S, 61, 56, 67 A [56] References Cited UNITED STATES PATENTS 1,831,697 11/1931 Ziegler 114/67 A 2,555,307 6/1951 Aylsworth 114/66.5 S 3,150,626 9/1964 lrgens 114/66.5 I-l 3,547,064 12/1970 Glass 114/66.5 S 3,602,179 8/1971 Cole 114/66.5 S 3,628,485 12/1971 Gill et a1 114/66.5 P FOREIGN PATENTS OR APPLICATIONS 660,557 4/1963 Canada 1l4/ 66.S 11

762,452 4/1934 I France l14/66.5 H

Primary Examiner-Milton Buchler Assistant Examiner-Barry L. Kelmachter Att0rney-Flehr, Hohbach, Test, Albritton & Herbert [57] ABSTRACT A hull construction in which displacement portions are carried to depend downwardly from the bottom surface of the hull and have a progressively increasing depth and width extending rearwardly along the bottom surface. The displacement portions terminate in a step. A planing surface is disposed adjacent the step to extend laterally across the bottom surface in a direction defined between the port and starboard chines of the hull and in spaced relation beneath the hull. The displacement portions and bottom surface serve to form flow passages commencing forwardly beneath the bottom surface, progressively diminishing in crosssection rearwardly beneath the hull,and terminating above the planing surface.

9 Claims, 8 Drawing Figures PATENIEDNUYZO mm 3.773. 006

INVENTOR. ROBERT B. BLACK ATTORNEYS PATENIEUunvzo 197s SHEET 2 OF 2 kw a @w A \mm/ g H I UIHIH INVENTOR. ROBERT B. BLACK F/MM IW uWIiII HI ATTORNEYS BACKGROUND OF THE INVENTION This invention pertains to a hull construction and more particularly to a hull construction useful'in planing across the surface of the water with limited wetted surfaces while maintaining stability and a substantially constant trim.

Typically, various types of planing hulls have been provided as, for example, in the step hydroplane wherein the bottom surface of the hull planes at a relatively low angle to the horizontal. Such'previous craft as are known typically are characterized by a handling characteristic of some substantial stiffness in the longitudinal direction as where the hull may tend to slap or pound relatively firmly against waves passing beneath.

Accordingly, it is desirable, if possible, to provide a planing hull which rides softly and eliminates this stiffness in handling without sacrificing stability or the ability of the craft to maintain a substantially constant trim angle. Accordingly, as disclosed herein, a hull construction is provided which substantially followsthe waves rather than driving directly through them so long as the height of the waves does not become too great.

SUMMARY OF THE INVENTION AND OBJECTS In general, there has been provided a hull construction wherein displacement portions are carried to depend downwardly from the bottom surface of the hull. These displacement portions have a progressively increasing depth and width commencing beneath the forefoot of the bottom surface and extending rearwardly along the bottom surface so as toprovidedisplacement portions having a cross-section of progressively enlarging area. A step is formed in the bottom surface intermediate the ends of the hull and the displacement portions terminate in the region of the step. Further, a planing surface is disposed adjacent the step and extends laterally between the port and starboard chines of the hull in spaced relation beneath the bottom surface of the hull. The displacement portions and bottom surface serve to form flowpassages or channels commencing forwardly beneath the bottom surface as at the forefoot and having progressivelydiminishing cross-section beneath the hull to terminate above the planing surface so as to funnel water across the planing surface as the water is tossed up beneath the hull.

Additional preferred features are provided herein so as to provide an improved planing'hull all as explained further below.

Accordingly, it is a general object of the present invention to provide an improved planing hull which solves the foregoing and other problems.

It is another object of the invention to provide a planing hull characterized by improved stability and substantially constant trim but without incorporating the characteristic longitudinal stiffness experienced in typical stepped-type planing hulls.

It is a further object of the invention to provide an improved planing hull of the type applicable for use in conjunction with sail boats, power driven hydroplanes, and various other types of craft.

The foregoing and other objects of the invention will be more readily evident from thefollowing detailed description of a preferred embodiment when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the bottom of a hull construction, according to the invention, as viewed in perspective view from beneath with portions broken away for clarity;

FIG. 2 shows a bottom plan view according to the invention;

- FIG. 3 is a side elevation view' of FIG. 2 according to I the invention;

FIGS. 4 and 5 are section views respectively taken along the lines 4-4 and 55 as shown in FIG. 3;

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The bottom of the hull construction as shown in FIG.

" 1 is characterized by somewhat pyramid-shaped disto provide outwardly and rearwardly angled substantially vertical step portions 16a flanking a slanting stepped surface 16b. Surface 16b, in turn, forms the rear surface of displacement portion 11. Thus, the displacement portions terminate in the region of step 16.

A planing surface member, referred to hereafter as a high speed planing surface 17, is disposed adjacent step 16 and carried by attachment to the trailing portions of displacement portions 11-13 which form substantially co-planar regions. Surface member 17' extends between the port and

starboard chines

18, 19 respectively for purposes as will be described further below. Planing surface member 17 is further disposed in spaced relation beneath the bottom surface of the hull so that the displacement portions and bottom surface 14 serve to form flow channels or passages 21, 22 (FIG. 4) commencing from beneath the forefoot of bottom surface 14 and having a progressively diminishing cross-section beneath the hull and terminating above planing surface member 17 so as to funnel the water which is tossed up beneath the hull directly into the region of planing surface member 17.

The high speed planing surface member 17 comprises a pair of substantially flat, elongated relatively broad, thin plate members 17a, 17b joined at one end to form a V-shaped planing surface which is secured at its lateral outer (i.e., outboard) ends in the region of

chines

18, 19 of craft 15. One edge, such as the trailing edge of each of the plate members 17a, 17b, lies in a common plane while the other edge of each plate member 17a, 17b, such as their leading edges, lies in a second plane which is spaced from the first plane so as to provide a forwardly and upwardly inclined slope to the two high speed planing plate members 17a, 17b. In this way, merely the trailing edge margins of members 17a, 17b constitute substantially the entire wetted surface of the high speed planing member 17 when the craft is operating at high speed.

Preferably, the planing surface member 17 is disposed so that the apex of the V-shaped planing surface is disposed in a leading position in advance of the tips of the V which it forms. At the outer ends of the V- shaped high speed planing member 17, a pair of relatively short fins 23 serve to provide the function of a keel, centerboard, or the like, as where the hull is employed in conjunction with a sail carried by a mast carried topside by the craft.

Aft of step 16 the bottom surface portion 24 is rela tively broad and flat bounded at its port and starboard edges by downwardly depending displacement portions or

shapes

26, 27 respectively which extend aft to the transom 28 of the boat. At that point, the two

displacement shapes

26, 27 are joined by a transversely extending rear planing plate 29.

The rear planing plate 29 has been provided for purposes as will be explained more fully below in conjunction with the operation of the hull construction and is constructed of a relatively elongated wide plate of generally flat construction having a wedge-shaped crosssection as shown best in FIG. 7. In general, the planing plate 29 serves to lift the stern of the craft when under forward movement so as to enable the craft to more readily obtain a planing attitude supported ultimately substantially solely on the high speed planing surface 17.

In addition to the above, the region immediately astern of step 16 has been vented by means of vent passages 31 extending from the bow of the hull rearwardly to exhaust aft of step 16 so as to disperse eddys created at that location.

in addition, bow wave deflecting means have been provided in the form of the V-shaped deflector 32 carried in advanced spaced relation with respect to the bow of the hull and comprising elongated plates disposed across and in advance of the bow at the water line of the hull at low speed for initially deflecting the bow wave and serving to from an air passage 33 (FIG. extending downwardly and rearwardly to supply air beneath the forefoot of the hull and also into the vent passages 31. The bow wave deflector quickly lifts the bow to diminish the resistance of the displacement portions ll-l3 and bottom surface 14.

Further, by providing the air passage 33, the bow wave deflecting means prevents suction and eddys as may occur forwardly under the hull section upon making changes in direction. The bow wave deflector 32 provides a relatively efficient means of ventilating step 16. Preferably, bow wave deflector 32 is fabricated with aluminum or plastic sheet/polystyrene foam sandwich panels for small craft. However, larger craft might require conventional deep V wave deflection.

The hull construction as shown and described above operates preferably as a small craft whereby at slow speed, the bow deflector 32 first quickly climbs the bow wave since there is typically negligible weight forward in the hull.

After the bow is up, the whole underside of craft l5 acts as a planing surface, whereby the stern subsequently rises somewhat. The bow wave is for the most part tossed up under the craft and discharged aft via the flow passages 21, 22 (FIG. 3) whereby as the craft picks up speed, the high speed planing surface 17 has increasingly less wetted surface friction and the displacement portions ll, l2, 13 have less immersion.

The shape of the under surface of the hull continues to discharge water aft upon which the stern planing surface member 29 tends to plane. With increasing speed, the high initial planing angle experienced by the craft puts a relatively high loading upon the after under surface 24 whereby the stern rises further to reduce the trim of the craft 15 until the craft is planing substantially only on the two

planing surfaces

17, 29. This, however, is only accomplished at a sufficiently high speed wherein the flatter planing angle reduces residual resistance and skin friction aft thereby allowing the craft to commence planing upon the two planing surfaces.

At this point, a slight shift in weight forwardly allows the after planing surface 29 to clear the water whereby substantially the entire load of the craft is carried upon the V-shaped high speed planing surface member 17 in a substantially stable condition.

In a theoretically ideal glassy surface water state, only the rear edge margin of planing surface 17 will be contacting the water' This is explained by the fact that the two planing surface members 17a, 17b are inclined at an angle on the order of 3 to provide a trim remaining substantially constant even at higher speed.

By comparison, on an ordinary planing hull, any attempt to carry the load on a wide, narrow strip of water typically results in unstable conditions referred to as porpoising. Further, in order to keep the trim of the craft at a relatively low angle, the ordinary boat hull must have substantial weight located forwardly thereby resulting in high longitudinal moments of inertia developing a certain handling stiffness in the boat.

In accordance with the present design, however, the loading is provided on a relatively stable planing surface with substantially fixed trim and low drag so as to allow the weight to be located above the water plane area. In this manner, the stiffness typically experienced in boats of this type is avoided and the boat will substantially follow the waters surface whereby any water which is encountered, and for which the boat cannot follow the waves surface, causes the after portions of the pyramid-shaped displacement portions to become wetted as water passes above the planing surface 17, and the stern planing surface 29 is also wetted. In this manner, the serious pounding which is typically experienced in other types of craft of a generally similar nature is avoided such as found in racing hydroplanes and the like.

it has been observed that the provision of flow passages above the two planing

members

17, 29 serves to provide the foregoing capability in permitting the hull to follow the surface of the water while for small irregularities in the water, the planing surfaces 17, 29 simply carve through the water with some of the smoothness of a hydrofoil or the like.

Further, it is to be observed that the keel and chines portions of the under surface of the craft become deeper-running progressively aft and then abruptly become stepped at a position intermediate the ends of the hull so that these shapes can act to provide the soft riding characteristics derived from an elongated forefoot for the craft thereby making it ride more comfortably on the water at high speeds as it remains continuously in contact with the water. Wave deflection is soft for waves the size of the height of the displacement portions 11-13. While the forward shapes are acting as displacement hulls, the after portion of the hull acts as a true planing craft at a very early speed.

From the foregoing, it will be readily evident that there has been provided an improved hull construction suitable for use in conjunction with small craft and other craft taking advantage of the features which are disclosed herein.

I claim:

1. In combination, a hull construction having a bottom surface, displacement portions carried to depend downwardly from said bottom surface, said displacement portions having a progressively increasing depth and width commencing forwardly beneath said bottom surface and progressing rearwardly therealong and forming substantially co-planar regions, a V-shaped planing member supported by said displacement portions at an inclined angle to the bottom surface in spaced relation beneath said bottom surface and extending transversely of the centerline of the hull.

2. In a hull construction the combination comprising a bottom surface, displacement portions carried to depend downwardly from said bottom surface, said displacement portions commencing forward beneath said bottom surface and progressing rearwardly along said bottom surface and forming substantially co-planar region, a step formed in said bottom surface, a planing surface disposed adjacent said step and extending laterally to and connected to the substantially co-planar regions of said displacement portions in spaced relation beneath said bottom surface, said displacement portions and bottom surface serving to form flow passages commencing forwardly beneath said bottom surface and terminating above said planing surface.

3. In a hull construction the combination comprising a bottom surface, port and starboard and displacement portions carried to depend fowardly from said bottom surface, said displacement portions having a progressively increasing depth and width commencing beneath said bottom surface and progressing rearwardly along said bottom surface, a step formed in said bottom surface, said displacement portions terminating in the region of said step and forming substantially co-planar region, a planing surface disposed adjacent said step and extending laterally in the direction defined between the port and starboard chines of the hull in spaced relation beneath said bottom surface and supported by the substantially co-planar region of said displacement portions, said displacement portions and bottom surface serving to form flow passages commencing forwardly beneath said bottom surface and having progressively diminishing cross-section beneath the hull and terminating above said planing surface.

4. In a hull construction according to claim 3, bow wave deflecting means carried in advanced spaced relation with respect to the bow of the hull and forming an air passage therebetween, and a vent passage extending aft from said air passage to exhaust aft of said step for dispersing eddys thereat.

5. In a hull construction according to claim 3 further including a vent passage extending from the bow of the hull to exhaust aft of said step for dispersing eddys thereat, bow wave deflecting means carried in advanced spaced relation with respect to the bow of the hull and comprising elongated, inclined plates disposed across and in advance of the bow at the water line of the hull at low speed for deflecting the bow wave and serving to form an air passage downwardly and rearwardly to supply air beneath the forefoot of the hull and into said vent passage, and further serving to quickly lift the bow to diminish the wetted surface resistance of said displacement portions.

6. In a hull construction according to claim 5 further including a transversely extending planing plate disposed in spaced relation beneath the stern of the hull for lifting said stern under forward movement of the hull.

7. In a hull construction according to claim 3 wherein said planing surface comprises a pair of substantially flat, elongate, relatively broad thin plate members disposed in a V-shaped configuration to provide planing surface portions, one edge of each of said plate members lying in a common plane and another edge, parallel to said one edge, of each of said plate members lying in a second plane spaced from the first named plane to provide an inclined slope to said members.

8. In a hull construction according to claim 7 wherein the apex of the V-shaped configuration is disposed in a leading position in advance of the tips of the V.

9. In a hull construction according to claim 7 wherein said plate members are joined at the apex of said V- shaped configuration.

( 73 I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION latent No. 3' 006 Dated November 973 ..RQBERT B. BLACK Invcntor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below} IN THE INVENTOR'S ADDRESS! I Cancel the Zip code "94121" and substitute therefor -94l, 22.-. v a IN THE CLAIMS: I

claim 2, column 5, lines 25 and 26, cancer --"region" and substitute therefor .-.-regions.;

Claim 3, column 5, line 35, after "starboard? insert c-hines,'--.

Claim 3, column 5, line 36, cancel "fowardly" and substitute therefor --dov mwardly.-

0 Claim 3, column 5, line 43, cancel "region'.' and substitute therefor --regions-.

Claim 3, column 6, line 1, .cancel "region" and substitutetherefor --re g'ions Signed and sealed this 7th day of May 197 4,.

(SEAL) Attest:

EDw-IARD M.FLETGI-ILR,JR. C. PLARSIIAILIL DANN Attesting Officer Commissioner of Patents

Claims

9. In a hull construction according to claim 7 wherein said plate members are joined at the apex of said V-shaped configuration.