US3160134A - Boat hull - Google Patents

Description

1954 H. F. HlLLMAN ETAL ,160, 3

BOAT HULL 3 Sheets-Sheet 1 Filed March 21, 1962 INVENTORS. //nz.e Y E A614 MI/I q irraxwiyr 1964 H. F. HILLMAN ETAL 3,160,134

BOAT HULL INVENTORS. //4,e4 55 4 Lamaze-(x1,

5 Sheets-Sheet 3 M vm 1/ 3 BY 57, :454/6. Can/orig M Filed March 21. 1962 United States Patent Ofiice ddfifiddd Patented Dec. 8, 1964 3,150,134 BSA! HULL Harry F. Hillrnan, Lake Forest, and Ralph E. Lambrecht and Warren C. Conover, Waukegan, llL, assignors to ()uthoard Marine Corporation, Waukegan, lit, a corporation of Delaware Filed Mar. 21, 1962, fier. No. 182,719 29 Claims. (Cl. 114-665) The invention relates generally to boats incorporating planing hulls. More particularly, the invention relates to three-point suspension hulls and to multiple-entry hulls.

A three-point suspension hull is defined as a planing hull including two forwardly located planing surfaces or areas located at opposite sides of the fore and aft center line of the boat hull, and an after planing surface or area extending along and symmetrically intersected by the longitudinal center line of the boat hull. A multipie-entry hull is defined as a unitary hull including more than one how formation which cuts the water during movement of the hull. It is known to provide three-point suspension, multiple-entry, planing hulls of contours other than that claimed herein.

Three-point suspension permits carrying relatively larger loads With relatively smaller and particularly less wide after planing areas. In addition, the use of more than one planing surface serves to stabilize the angle of attack during planing while the use of two forward planes provides stability against rolling or side-to-side rocking of the hull. Angle of attack is defined as the angle measured in the direction of movement, between a planing surface and the theoretical surface level of the water. The multiple-entry feature aids steering by preventing broaching, serves to facilitate beaching of the hull with the center line thereof in generally perpendicular relation to the shoreline, and serves to minimize side-to-side tipping, both when the boat is beached and when it is afloat.

The invention contemplates a hull providing the above features, as well as other advantages. Specifically, the hull disclosed herein serves to avoid or eliminate cavitation and turbulence in the stream of water acted upon by the propeller. As used herein, cavitation generically refers :both to technical cavitation and to ventilation. Technical cavitation is the formation of vapor pockets in the path of the propeller in which the pressure is essentially equal to the vapor pressure of the surrounding water. Ventilation is defined as the formation of air pockets in the propeller stream due to entrapment of air under the boat hull. Air may also be introduced into the Water in the path of the propeller by turbulence, which is defined as a condition of agitation produced, for example, by the entry of a bow formation through water. In general, undesirable air pockets are usually present in turbulent water.

Reduction of turbulence and cavitation in the path of the propeller is achieved by the use of a triple-entry, three-point suspension hull including a bow incorporating (1) a center bow formation and a pair of laterally spaced, forwardly located sponsons providing planing surfaces, and (2) means in the form of fins or spoilers which project downwardly in parallel relation to the center line in the area between the sponsons' and the center bow formation. The spoilers are spaced outwardly at opposite sides of the area into which the propeller or propellers are advancing. Preferably, the spoilers are located inwardly of the junction of the wakes from the center bow formation and the respective sponsons. The spoilers act as baffles or barriers tending to exclude turbulence created by the inside surfaces of the sponsons from entering the otherwise quiescent water in the path of the propellers. This is of particular importance during acceleration or in a following sea.

In the preferred embodiments, the spoilers extend rear- Wardly from points adjacent the bow and terminate adjacent the transom, thereby providing barriers extending substantially the full length of the hull against the introduction into the path of the propeller of turbulent water from the wake of the sponsons. When the spoilers extend to the transom, they contribute materially to the lateral area which is wetted. The term wetted lateral area, as used herein, is defined as the projected area of each part of. the hull below the water line in the profile view plus the projected area of each keel and spoiler below the waterline; that is, the projected area of each sponson is counted even through the projections coincide and the projected area of each spoiler is counted although they coincide and overlap with the hull projection over part of their length. Wetted lateral area is important, in relation to the center of gravity, in obtaining superior turning action. In some embodiments, use of a downwardly projecting keel or center fin along the after portion of the hull can be dispensed with.

If desired however, the spoilers may terminate substan tially forwardly of the transom, but aft of the forward planing surfaces, and a downwardly projecting keel or center tin can be employed aft.

Turbulence in the path of the propeller is also avoided by constructing the after plane with a positive dead rise angle, so as to effect lateral displacement of any turbu lence created by cutting-of the water by the forward point. of the after plane. The inclusion of a dead rise angle in the after plane also aids in proper boat control and banking during turns.

Dead rise angle is defined as the angle, measured in a station between the base plane (or base line) and the laterally extending part of the station (or station line) extending generally from the lowest point on the station. Base plane is defined as the plane defined by the lowest point of each of the three planing surfaces. Station is defined as a transverse section perpendicular to the base plane and to the fore and aft center line of the hull.

The disclosed construction also advantageously facilitates planing of the boat hull at an optimum angle of attack with the center bow formation at least partially submerged in the water to assist in providing in the path of the propeller a stream free of turbulence and cavitation. The optimum angle of attack represents that angle wherein the sum of frictional resistance and wave-making resistance is at a minimum. Travel of the hull at its optimum angle of attack, while retaining at least 'a part of the center bow formation in the water, is obtained by the provision of a knuckle or break in the angle of incidence of the after plane.

Angle of incidence is defined as the angle, measured at any buttock, between the base plane and any partor extension of the buttock (or buttock line) intersecting the base plane. Buttock is defined as a fore and aft section perpendicular to the base plane and parallel to the fore and aft center line.

As a result of the break or knuckle in the after plane, the planing area forwardly of the knuckle has an angle of incidence less than the angle of incidence of that portion of the after plane rearwardly of the knuckle. In the disclosed construction, the forward portion of the after plane extends parallel to the base line, thereby providing a generally triangular planing area having a less sharply converging, forwardly projecting extension provided, at its foremost extremity, by a portion of the central bow formation.

Such an after plane formation additionally serves to increase the distance between the propeller and the extreme forward end of the after plane so as to further remove the 3 propeller from the area where turbulence is created by passage of the central bow formation through the water.

In addition, the disclosed construction is designed to provide a soft ride, i.e., to reduce the pounding which commonly occurs incident to crossing a series of two or more waves, and to aiford better steering control. More particularly, these advantages are obtained by reason of the use of a pair of relatively narrow sponsons having relatively large dead rise angles, which sponsons are symmetrically located with respect to the center line of the hull and are each generally symmetrical about their individual center lines, at least in the area normally subject to wetting during planing. This symmetry of design is specifically advantageous, coupled with the multiple-entry feature, in preventing broaching.

The sponson construction is also designed to avoid suction loads during movement through the water. Such loads are undesirable as they tend to reduce speed and may tend to rock the boat if the sponsons are not subject to substantially equal suction loads. This rocking effect is particularly noticeable during turns and when crossing waves when the depth of submergence of the sponsons may be different. Moreover, unequal suction loading during a turn noticeably hinders return of the boat to a straight course.

Avoidance of suction loads is obtained by fabricating the sponsons with an absence of downward convexity and by the provision of buttocks having portions which are straight throughout the area normally subject to wetting during planing.

In addition to the before-mentioned advantages, including softer ride, better steering control and superior power utilization due to a minimum condition of turbulence and cavitation in the path of the propeller, the disclosed hull provides, as a result of its multiple-entry bow, an exceptionally large area available for use as a passenger cockpit, substantially increased forward buoyancy, and superior stability against undesired tilting or tipping in any direction. Still further, the bow formation of the disclosed hull produces little wave generation or reflection during movement through the water, thereby also minimizing spray. It also serves to locate the center of gravity of the boat at a relatively more forward position than was heretofore generally the case.

Other objects and advantages of the invention will become apparent by reference to the following description and the accompanying drawings in which:

FIGURE 1 is a side elevational view of a boat hull embodying various of the features of the invention;

FIGURE 1a is a fragmentary side elevational view of a modified embodiment of boat hull incorporating various of the features of the invention;

FIGURE 2 is a front elevational view of the boat hull shown in FIGURE 1;

FIGURE 2a is a fragmentary front elevation view, similar to FIGURE 2, of the modified boat hull shown in FIGURE 1a;

, FIGURE 3 is a rear elevational view of the boat hull shown in FIGURE 1;

FIGURE 3a is a fragmentary rear elevational view, similar to FIGURE 3, of the modified boat hull shown in FIGURE 1a;

FIGURE 4 is a buttock or fore and aft sectional view taken generally along line 44 of FIGURE 2;

FIGURE 4a is a fragmentary buttock or fore and aft sectional view, similar to FIGURE 4, showing the corresponding buttock of the boat hull shown in FIGURE 1a;

FIGURE 5 is a fragmentary buttock or fore and aft sectional view taken generally along line 5-5 of FIG- URE 2;

FIGURE 5a is a fragmentary buttock or fore and aft sectional view, similar to FIGURE 5, showing the corresponding buttock of the boat hull shown in FIGURE 1a;

FIGURE 6 is a fragmentary buttock or fore and aft l sectional view taken generally along line 6-6 of FIG- URE 2;

FIGURE 7 is a fragmentary buttock or fore and aft sectional View taken generally along line 77 of FIG- URE 2;

FIGURE 8 is a composite half station or transverse sectional view taken generally along lines ll-l, 22, 3-3, 4- 4, 5-5, 6-6, and 7-7 of FIGURE 1; and

FIGURE 9 is a composite half station or transverse sectional view taken generally along lines 88, 99, and iii-4ft) of FIGURE 1.

The planing hull ill shown in FIGURE 1 of the drawings can be unitarily constructed of plastic and is symmetrical about its fore and aft center line 13 (line 4-4; of FIGURE 2). The planing hull 11 includes a multipleentry bow 15 including a central bow formation 17 and a pair of how formations 1% respectively forming one part of each of a pair of laterally spaced sponsons 2:1. The sponsons 21 provide forward supporting surfaces or planing areas 22 (see FIGURE 1), and together with an after plane, indicated generally by the numeral 23, provide stepped-three-point suspension. The sponsons 21 also serve to laterally enlarge the bow is" and merge with the sides 25 which extend aft to a transom 27.

Extending aft from a point between each of the sponsons 21 and the central bow formation 19, in fore and aft parallel relation to the center line 13, is a spoiler 29. In the embodiment shown in FIGURE 1, the spoilers 29 terminate rearwardly of station 3- and prior to station 9, as shown in FIGURES 8 and 9 and in FIGURE 5, and a fin 31, projecting downwardly along the center line 13, is provided. However, in the boat hull I'll, as shown in FIGURE 1a, which boat hull is generally of identical construction to the boat hull Iii except as will be noted, the spoilers 129 are extended to adjacent the transom I27 and the fin fill is omitted as sufficient wetted lateral area can be obtained by proper vertical sizing of the spoilers 129. Extension of the spoilers to adjacent the transom 12.7 serves to provide a barrier, extending almost to the propeller area, against the entry of turbulence into the path of the propeller.

Considering the construction in greater detail, each of the sponsons 21 is symmetrically located relative to the center line 13 and is symmetrical about its own center line b3, at least in the area normally subject to wetting durlng planing. Each of the sponsons 21 is relatively narrow and, as shown in FIGURE 8, includes, at each station, a substantial dead rise angle, thereby providing a relatively soft ride and contributing to minimum wave reflection.

Each sponson 21 is also constructed, as seen best in FIGURE 8, so that each station extends in a straight line from each side of its center line 33 (stations 4 through 7), or is downwardly concavely facing on each side of its center line 33 (stations 1, Z, and 3). Moreover, each sponson 21 is also constructed so that the buttocks are straight, as seen in FIGURES 6 and 7, at least in the area normally subject to wetting during planing. The provision of straight or downwardly concave stations together with straight buttocks avoids any downward convexity in the sponsons, and thereby eliminates suction loading thereof.

The after plane 23 extends forwardly from the transom 27 until merging with the central bow formation 17 and, as seen best in FIGURE 9, it includes, at each station, a positive dead rise angle aifording lateral displacement of any turbulent condition created by passage of the central bow formation 17 through the Water. The construction of the after plane is also free of any downward convexity. In addition, the after plane 23 includes a knuckle or break 35, shown best in FIGURES 1 and 4. The knuckle 35 generally divides the after plane into an aft portion 37 having substantially the same angle of attack as the sponsons 21 and a forward portion 39 which has a zero angle of attack and which includes a progressively increasing dead rise angle, thereby effecting transition of the after plane 23 into the central bow formation 17 generally in the area of station 6. Breaking of the after plane, as indicated at 35, extends the rearward planing surface forwardly to at least partially submerge the central bow formation 17.

The central bow formation is symmetrical about the,

center line 13 and, as seen best in FIGURE 2, is of less depth than the sponsons at all stations and merges into the after plane at or near station 6. As can be seen from FIGURE 8, each of stations 1 through 6 is either straight or downwardly concave on each side of the center line 13. Each station of the central bow formation 17 also includes a positive dead rise angle. If desired, the central bow formation can be omitted, while retaining certain of the advantages of the invention, as for example, the soft ride, and the resistance to broaching.

Extending rearwardly into the after plane along the center line 13 of the hull from the central bow formation 17, is the central keel or fin.31. The fin 31 begins to appear at about station 6 and extends almost to the transom 27, providing suificient wetted lateral area to resist sidewise shifting or sliding during turns.

The spoilers 29 extend between the sponsons 21 and the central bow formation 17 from about station 2 to beyond station 8, i.e., Well beyond the rearward end of the sponsons 21, and as seen best in FIGURE 8, provide a generally vertical surface or bafiie 41 against passage of turbulence from the sponsons to the propeller path, while presenting inwardly and downwardly concave sides or surfaces 43 toward the central bow formation 17, thereby tending to deflect curvilinearly downwardly any turbulence created by passage of the central bow formation 17 through the water, and thereby permitting passage of such turbulence past the spoilers 29 and out of the propeller path.

As can be seen from the drawings, the side and trailing edges of the planing surfaces terminate abruptly along sharp lines, thereby preventing water from following. In particular, at the rear of each sponson 21, there is provided a vertical step in order to mark abruptly the end of the sponsons. Preferably, the step is only of such height as will prevent following of the water, and there extends, from the top margin of the step, an arched portion of the hull which extends rearwardly and merges into the after plane. The arched portion, indicated at 45, provides improved structural strength over that which would result if the rear surface of the sponson were completely or substantially planar.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

1. In an integral multiple-entry planing hull including a bow having a sponson spaced laterally on each side of the center line of said hull and an after plane extending aft of said sponsons, the improvement comprising sponsons which are symmetrical with respect to said center line and which are individually symmetrical at every station at least Within the area normally subject to wetting during planing.

2. A boat hull in accordance with claim 1 wherein each of the sponson stations incorporates a positive dead rise angle, and is free of convexity within the area normally subject to wetting during planing.

3. A boat hull in accordance with claim 1 wherein each sponson buttock is straight within the area normally subject to wetting during planing.

4. A boat hull in accordance with claim 1 wherein each sponson station incorporates a positive dead rise angle and is free of convexity within the area normally subject to wetting during planing, and each sponson buttock is straight within the area normally subject to wetting during planing.

5. In a three-point suspension planing hull including an after plane and two laterally spaced forward planes disposed at acute angles to the base line, the improvement comprising means providing a break in said after plane midway of its fore and aft length with the portion of said after plane forwardly of said break being disposed at a lesser acute angle to the base line than the portion of said after plane re arwardly of said break.

6. A boat hull in accordance with claim 5 wherein said forward portion of said after plane has a zero angle of incidence.

7. A boat hull in accordance with claim 5 wherein each station through said after plane includes a positive dead rise angle.

8. A boat hull in accordance with claim 5 wherein each station through said after plane is free of downward convexity in the area normally subject to wetting during planing and each station through said after plane includes a positive dead rise angle.

9. In an integral multiple-entry planing hull including a center bow formation merging into an after plane and a laterally spaced sponson on each side of said bow formation providing a pair of laterally spaced forward planes, with said planes being disposed at acute angles to the base line, the improvement wherein said sponsons are symmetrical with respect to said bow formation and are individually symmetrical at every station at least within the area normally subject to wetting during planing, and

said after plane incorporates a break therein midway of its fore and aft length, thereby defining a forward portion and an after portion, said forward portion of said after plane being disposed at a lesser acute angle to the base line than the rearward portion of said after plane.

10. A boat hull in accordance with claim 9 including a downwardly projecting spoiler extending parallel to the center line of the hull between each of said sponsons and said center bow formation.

11. A boat hull in accordance with claim 10 wherein said hull includes a transom, and said spoilers extend through said after plane substantially to said transsom.

12. A boat hull in accordance with claim 10 wherein said spoilers each include a portion having a concave surface on the side thereof adjacent to said center bow formation and a generally vertical surface on the side thereof facing outwardly of the center line.

13. A boat hull in accordance with claim 9 wherein each station through said after plane includes a positive dead rise angle and is free of downward convexity in the area normally wet during planing.

14. An integral, multiple entry planing hull including a bow having a sponson spaced laterally on each side of the center line of said hull, said sponsons each being symmetrical with respeot to said center line and each being individually symmetrical at every station at least within the area normally subject to wetting during planing, an after plane extending aft of said sponsons, a transom, and a downwardly projecting spoiler extending pmallel to said center line between each of said sponsons and said center line and extending along said after plane substantially to said transom.

15. An integral, multiple entry planing hull including a transom, a bow having a sponson spaced laterally on each side of the center line of said hull, said sponsons each being symmetrical with respect to said center line, each being individually symmetrical at every station Within the area normally subject to wetting during planing, and each terminating substantially forwardly of said transom, an after plane extending aft of said sponsons, a downwardly projecting spoiler extending panallel to said center line between each of said sponsons and said center line, said spoilers terminating substantially forwardly of said after plane and rearwardly of said sponsons, and a fin projecting downwardly from said after plane along said center line to a point near said transom.

16. An integral, multiple entry planing hull including a bow having a sponson spaced laterally on each side of the center line of said hull, said sponsons each being symmetrical with respect to said center line and each being individually symmetrical at every station at least Within the area normally subject to wetting during planing, and a downwardly projecting spoiler extending parallel to said center line between each of said sponsons and said center line, each of said spoilers including a portion having a generally Vertical surface facing outwardly from the center line of said hull.

17. An integrfl, multiple entry planing hull including a bow having a sponson spaced laterally on each side of the center line of said hull, said sponsons each being symmetrical with respect to said center line and each being individually symmetrical at every station at least within the area normally subject to wetting during planing, a downwardly projecting spoiler extending parallel to said center line between each of said sponsons and said center line, each of said spoilers including a portion having a generally vertical surface facing outwardly from the center line of said hull, and an inwardly facing concave surface on the side thereof adjacent to said center line.

18. An integral, multiple entry planing hull including a transom, a bow having a sponson spaced laterally on opposite sides of the center line of said hull, said sponsons each terminating forwardly of said transom, each providing a planing surface, each being symmetrical with respect to said center line, each being symmetrical with respect to its own center line within the area normally subject to wetting during planing, each including a positive dead rise angle within the area normally subject to wetting during planing, each being free of downward convexity within the area normally subject to Wetting during planing, and, at each buttock, each being straight within the area normally subject to Wetting during planing. 7

V 19. An integral, multiple entry planing hull including a transom, a bow having 'a sponson spaced laterally on opposite sides of the center line of said hull, said sponsons each being symmetrical with respect to said center line,

each being individually symmetrical at every station at least within the area normally subject to wetting during planing, and each terminating forwardly of said transom.

20. An integral, multiple entry planing hull including a transom, a bow having a sponson spaced laterally on each side of the center line of said hull, said sponsons being symmetrical with respect to said center line, being individually symmetrical at every station within the area normally subject to wetting during planing, and terminating forwardly of said transom, and an after plane extending along said center line between said sponsons and said transom.

References Cited in the tile of this patent UNITED STATES PATENTS

Claims (1)

1. IN AN INTEGRAL MULTIPLE-ENTRY PLANING HULL INCLUDING A BOW HAVING A SPONSON SPACED LATERALLY ON EACH SIDE OF THE CENTER LINE OF SAID HULL AND AN AFTER PLANE EXTENDING AFT OF SAID SPONSONS, THE IMPROVEMENT COMPRISING SPONSONS WHICH ARE SYMETRICAL WITH RESPECT TO SAID CENTER LINE AND WHICH ARE INDIVIDUALLY SYMMETRICAL AT EVERY STATION AT LEAST WITHIN THE AREA NORMALLY SUBJECT TO WETTING DURING PLANNING.

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