US2423860A - Hydroplane boat hull form - Google Patents

Description

y 5 1947- Y c. D. VAN PATTEN 2,423,860

V HYDROPLANE BOAT HULL FORM Filed Aug. 20, 1945 3 Sheets-Sheet l y 15,1947. c. D. VAN PATTEN 2,423,860

HYDROPLANE BOAT HULL FORM Filed Aug. 20, 1945 s Sheets-Sheet 2 INVENTORQ Patented July 15, 1947 UNITED STATES PATENT OFFICE HYDROPLANE BOAT HULL FORM Charles Douglas Van Patten, Flint, Mich. Application August 20, 1945, Serial No. 611,537

9 Claims.

This invention relates to power boats, Vessels, seaplanes and flying boats of the type having a hull or hulls adapted to provide hydrostatic floatation while at rest in the water and a planing or hydrodynamic lifting reaction when forwardly propelled through the water, the principal object being the provision of a new and novel form of hydrodynamic lifting surfaces for such craft which include those forms commonly known as hard-chine hulls and hydroplanes.

Objects of the invention include the provision of a novel form of planing o'r lifting surfaces for a boat of the type described by the use of which the area of wetted surface is considerably .reduced, as compared with conventional constructions, during movement of the boat through the water and by the use of which the entrance wave is prevented from coming in contact with the greater portion of those surfaces which it is not actually reacting against to produce lift; the provision of a planing surface construction for boats and the like so constructed and arranged as to utilize whatever hydrodynamic lifting effort is required and no more; the provision of a planing surface or surfaces for a boat Or the like which will so condition the water over and through which the boat passes as to reduce the surface frictional resistance of the boat to forward motion; the provision of a planing surface construction by the use of which the wave making or residual resistance is substantially reduced, as compared to conventional forms, during movement of the boat through the water; and the provision of a planing surface or surfaces for a boat in which the tendency to compress the water against the Planing surfaces or any part contiguous thereto during its movement outwardly from the keel is largely eliminated. 7

Other objects consist in the provision of a planing surface or surfaces for boats or the like, the use of which largely eliminates the adhesion of water contained in the entrance wave to the bottom of the boat and the consequent abnormal raising of that entrance wave, thereby permitting the use of more easily driven and more seaworthy shapes than are possible in conventional constructions; the provision of a planing surface or surfaces so constructed as to considerably reduce the air resistance of the boat to forward movement by permitting a part of the air that would normally be forced aside to pass under the boat; the provision of a novel form of planing surfaces for a hydroplane of the stepped type so constructed as to greatly reduce the disadvantages present in conventional constructions due to the 2 formation of a region of low atmospheric pressure immediately abaft or back of such step or steps; and the provision of a planing surface or surfaces for boats or the like, the use of which largely overcomes the depressant or weighingdown effect of the atmospheric head on the boat, wherein such head tends to fill "the trough immediately rearward of the entrance wave, by allowing atmospheric access and air passage immediately beneath such surfaces;

Further objects include the provision of a planing surface or surfaces for a boat of the class described having special provision for reducing the area in contact with the Water in accordance with the weight and speed of the boat without impairing the lateral stability of the boat either in turning or moving in a straight line; the provision of a boat planing surface or surfaces so constructed as to materially increase the directional stability over that obtained with conventional constructions; and the provision of a planing surface or surfaces for a boat of the class described by the use of which the longitudinal stability is increased, ascompared with conventional constructions, without increasing the area of wetted surface over that required for most efficient planing of the boat.

Still further objects include the provision of a boat of the class described in which a series of generally longitudinally extending jogs on opposite sides of the keel extend in either parallel relationship to each other and to the keel or in converging relationship with respect to the keel and/or to each other, toward the stern of the boat, and in which each of the generally longitudinally extending jogs is made up of a plurality of shorter portions, preferably parallel with each other a viewed in plan, and each displaced or offset toward the keel from that one immediately forwardly thereof; the provision of a boat of the class described having a planing surface or surfaces of the above described type in which each such portion of a jog is offset from the next preceding or following portion by a distance no greater than the width of the intersected jogged surface; and the provision of a boat of the class described, in which the jogged and offset surfaces may be conveniently provided by suitably lapping the hull strakes; the provision of a boat of the class described having a planing surface or surfaces of the above described type so formed as to have the generally longitudinally extending jogs tapering in depth to zero at their forward and/ or rearward ends.

Still another object of the invention is the pro- 3 vision of a planing surface structure for a flying boat or seaplane which will enable it to more readily and easily lift from the water than is possible with conventional structures.

The above being among the objects of the present invention, the same consists in certain novel features of the construction and combinations of parts to be hereinafter described with reference to the accompanying drawings, and then claimed, having the foregoing and other objects in View.

In the accompanying drawings which illustrate suitable embodiments of the present invention Fig. l is a side elevational view of a planing type of boat, commonly known as a-hydroplane, in which a suitabl embodiment of the present invention is incorporated;

Fig. 2 is a bottom view of the boat shown in Fig. 1;

'Fig; 3 is an enlarged transverse sectional view of the boat shown in Figs. 1 and 2 taken on the line 33 of Fig. 2;

Fig. 4 is an enlarged transverse sectional view of the boat shown in the previous figures taken on the line 4'4'of Fig. 2

Fig. 5 is an enlarged fragmentary plan View of a portion of the boat bottom as illustrated in Fig.

2, showing the action of the offsets on the flow of water contacting the vertical surfaces of the jogs;

Fig. 6 is 'a bottom view of a boat of the planing type, generally similar to the boat shown in Figs. 1, 2, 3, and 4, but in which the embodiment of the present invention incorporates offsets of a greater I lateral dimension than those shown in Fig. 2;

Fig. 7 is a side elevational view of a hydro- -plane of the step type to which the present invention has been adapted; 1

'Fig. 8 isa bottom View of the boat shown in Fig. 5;

Fig. 9 is an enlarged transverse sectional view of the boat shown in the previous two figures taken on the line 9-9 of Fig. 8;

Fig. l0'is an enlarged transverse sectional view of the boat shown in the previous two figures taken on the lin Ifi-lil of Fig. 8;

Fig. 11' is; a partially broken side elevational view of the hull of a flying boat, showing the application of the present invention thereto;

Fig. 12 is a bottom view 'of the boat hull shown in Fig. 11; and,

Fig. 13 is an outline cross-section of the boat hull shown in Figs. 11 and 12, as on the line l3-l3 of Fig. 12. a s a Ideally, a boat having a bottom consisting of one or more fiat or nearly fiat planing or lifting surfaces, when propelled at speed on the water,

would move over the surface of the water rather than through it. Due, however, to the fact that water is'a fluid, that the boat has mass or weight, that surface friction occurs between the wetted surface of the boat and the water, and that therefore there is a tendency to displace water, ideal planing never actually occurs. I he proximity to which ideal planing is approached is dependentupon th relationship which exists between the mass of the boat, the speed, and the hydrodynamic reaction characteristics of the planingsurfaces of the boat.

It is also true in practically all constructions that-an entrance wave is created at the line or point where-the entering edge first'impinges upon the water. This wave is deflected by the force of forward movement of the boat hull in a generally outward, upward and rearward direction in relation to the hull. This wave, therefore, comes in continuous contact with the planing surface or surfaces and in conventional constructions remains in continuous contact with the planing surface to the outer edges of same. For purposes of analysis the lift or planing effort created by the entrance wave can be considered as an adjunct to that created by certain of the other hydrodynamic phenomena, related to the planing surface or surfaces and the forward movement of the boat. It is my theory that this wave factor is of great important in the action of planing boat surfaces on and in the water,

because the outward, upward and rearward movement of the water contained therein not because it produces increased wetted area due to its adhesion to the planing surfaces and consequently increased resistance to forward movement.

Among the principal objects of the present invention are the elimination of the greater part of that portion of the wetted area due to adhesion and the consequent abnormalraising of the entrance wave, increase of the effective lifting or planing effort created by the entrance wave, and substantial reduction of that portion of the remaining wetted area not producing an effective planing or lifting effort. In other words, one theory of my invention is to so form the planing surfaces as to utilize whatever hydrodynamic lifting effort is required to maintain the boat at the most efiicient point of planing, and no more, and to eliminate as far as possible any contact of the hull with the water not directly utilized for lifting purposes.

Specifically, the manner in which this result is accomplished is to form each major planing or lifting surface of a multiplicity of smaller planing surfaces whose greatest dimensions lie in directions preferably varying from parallelrelationship with the keel to complementary diagonal relationship onopposite sides of the boat, each of the latter planing surfaces being vertically displaced from the adjoining ones in an upward direction laterally toward the nearer bilge and the stern, thereby forming a jog between each of the latter planing surfaces. the present invention, these jogs are not of a continuously unbroken character in extending from the corresponding chine to the stern, keel, step or other surface where they run out and their rearmost end, but instead are modified from such a construction. According to one viewpoint, they maybe considered as relatively short jogs arranged in series or in groups, each one of each series or group being parallel to the rest of those 7 in the same series or group and inwardly offset towardthe keel from that one thereof immediately forwardly thereof. According to another viewpoint, each jog may be considered as continuous as above described, but successive longitudinal portions of which are offset inwardly from one another in a rearward progression, with a sharp break between adjacent offsets.

The action of such a construction in the water is considerably different from that of constructions heretofore proposed. Upon impinging at the keelor entering edge and being deflected in a relatively outward, upward and rearward direction, the water, due to its own inertia, is freed of contact with the planing surface of the boat at 'the point where these jogs occur, which greatly Now in accordance with the resistance of the boat to forward movement.

With-such constructions at certain speeds and on certain portions of the bottom the deflected water will leave the jog and flow relatively outwardly and rearwardly again coming in contact with the next laterally outward planing surface, this action continuing until the water has passed the rearward or the bilge extremities of the boat, or by its own inertia takes a course not in contiguity with the surface of the boat. Again, with such construction and at certain other speeds and on other portions of the bottom the water may be deflected into contact with the generally vertical surface of a jog and adhere thereto, thus defeating the purpose of such jogs at such area, resulting in undesired wetted areas, increased drag,,and consequent reduction in efficiency. The offsets in such jogs provided in accordance with the-present invention remedy this defect in that where any water tends to adhere to the vertical surface of any jog, as soon as it reaches the rear end of the corresponding offset, due to its own inertia its adhesion is broken and it is freed of contact with the vertical surface of the jog.

In the ordinary type of stepped hydroplanc construction as conventionally practiced, the forward motion of the boat through the water creates a region of reduced atmospheric pressure back of the step or steps and the stern. This low pressure region, in attempting to relieve itself, draws both air and water into the space behind such step or steps or stern, and tends to draw the surface water up into contact with the bottom of the boat, thereby creating resistance to forward motion to a much greater degree than would occur were this low pressure eliminated. The present invention is of material advantage in this respect as the generally longitudinally extending jogs in combination with the rearward movement of the water and air relative thereto and the provision of the offsets to aid in breakin the tendency of the water to adhere to the boat, all as above explained, induces considerable amounts of air that would'ordinarily be forced aside to pass under the boat, thereby relieving to a great extent the region of low pressure that would ordinarily exist back of such step or steps or stern.

Generally speaking, the application of the present invention is best made to those types of boat planing surfaces shown and claimed in United States Patent No. 1,935,622, issued Nov. 21, 1933, to George G. Eddy, and United States Patent No. 2,039,586, issuedMay 5, 1936, to George G. Eddy and myself. The form shown in the latter of these two patents has been selected herein as the type to which the present invention is shown in the accompanying drawings, but it is to be understood that the application of the present invention is not limited to the specific constructions covered by the above identified patents but is broadly applicable to any construction embodying stepped or jogged surfaces of the general type or effect shown.

Referring now to the drawings and particularly to Figs. 1 to 5, inclusive, it will be noted that there is shown in these figures a boat of the planing or semi-planing type having a singl major planing area, the particular type of boat shown being what is known commonly as a monoplane. In the novel construction of this type of boat the bottom portions of the bow sections usually show straight, concave or convex V formations and generally flatten out as they approach the stern section which is usually approximately flat or has a very large included angle. The boat shownin 6 Figs. 1 to 4, inclusive, is of this general type that its lower surfaces in the bow sectionsshow a generally deep V conformation and the stern sections are of shallower or more nearly fiat shape.

The boat shown includes sides l fl, deck l2, stern l4, and bottom indicated generally as at I 6. As indicated in Figs. 3 and 4, the boat is preferably provided with a keel 18 or equivalent structure, ribs or frame members -2-il and 22 of asuitable nature, and stringers 24 of generally longitudinal disposition. Each side or panel of the bottom 16 on Opposite sides of the keel 181s complementary to the other side, both sides being symmetrically arranged with respect to the keel and to a plane of symmetry passing centrally through the keel. Each half or panel of th bottom it on opposite sides of the keel 1-8 is formed of a plurality of smaller planing surfaces 26, '28, 30, 32 and 34, each of which extends longitudinally to diagonally of the boat and is separated from the next adjacent planing surface or surfaces by a generally vertical jog or jogs M), the vertical surfaces of which jogs face outwardly and in directions toward the nearer bilge and the stern. The jogs '29 may continue for full or varying depth from the bilge to the stern or keel. They may fade out at their forward ends, at or adjacent the bilges or chines, or may fade out at or adjacent their rear ends, at or adjacent the stern ill or the keel 18 depending upon which of these they Would intersect if carried through or may fade out at both ends, which is the construction shown by way of illustration and preference. It will be appreciated that where they thus fade out the planing surfaces beyond them and which would otherwise be separated by them merge together in smooth relationship.

In accordance with the present invention the jogs ll}, or at least most of them, depending upon their lengths and disposition, are not of a continuously unbroken character, but rather each is made up of a plurality of shorter parallel portions each of which is inwardly offset or displaced from that portion immediately forwardly therefrom, toward the keel. On the other hand, each of such short portions may itself be considered as a jog 49, and such portions thus arranged in groups, the portions of each group being parallel in plan, or approximately parallel, with each other, and progressively offset from one another toward the keel in rearward progression. In such case the jog portions M) of each group-are arranged in complementary relation on either side of the plane of symmetry passing centrally through the keel, the jog portions of all groups preferably, but not necessarily in all cases, being arranged at an acute angle with respect to such plane in rearwardly converging relation with respect thereto and preferably with increasing angularity in outward progression from such plane, as shown,

Regardless of how the above is considered, there is a sharp break between each succeeding portion of each jog 48, when considered as first described, or between each pair of adjacent jogs all of each group when considered as last described, forming a lateral surface 4'2, best brought out in Fig.5. These surfaces 42 are not required to be perpendicular to the lengths of the corresponding jogs 40 or portions thereof, but their outer edges should join or intersect the forward of the corresponding jogs or portions 49 at a suflicient angle to provide the sharp break required to free water, under its own inertia, flowing along the jog 4-0 or portion thereof immediately, forwardly thereof, when the boat is travel ing at speed.- In the particular, form of the surfaces: 42 shown by way of illustration, the planes of the surfaces 42, are perpendicular to the planes of the corresponding jogs or portions 40 which they connect, at their outer ends, and are curved into merging relationship with the rearwardmost of such corresponding jogs or portions All at their inner ends. Each such portion of the jogs G0, or each jog 40 of each said group, depending upon how considered, are preferably, but not necessarily, of the same or approximately the same length or longitudinal dimension.

In the operation of the above described boat, and referring particularly to Fig. 2, let it be assumed that with the boat at speed the water will first impinge upon the boat at a'point on the keel such as X. The impingement of the water on the boat will cause what is commonly known as an entrance wave and which entrance wave will be deflected and have a relative flow along a line such as A rearwardly, outwardly and upwardly with respect to the bottom of the boat. In conventional constructions, this entrance wave which necessarily spreads as it moves relatively rearwardly, outwardly, and upwardly, will remain in contact with the bottom of the boat for the full distance from the keel to the outer edge of the bilge or chine, even when such edge is well above the normal surface of the water over and through which the boat is moving. The reason for this occurrence in conventional constructions is that the bottom of the boat is a smooth unbroken surface and the adhesion of water to such a surface carries the entrance wave on up the bottom until it is finally freed at the outer edge of the bilge, which bilge, if it'be of the hardchine form as shown, exercises the same functions as the above described jogs but in a minor and much less effective way.

Now in accordance with the present invention when incorporated in a boat of the type shown in Figs. 1 to 5, inclusive, when the boat attains its speed the bow will tend to lift and the boat will tend to have a planing action on the water. Accordingly, due to the fact that the water has an outward, upward and rearward movement relative to the bottom of the boat, there will be a reaction between the bottom of the boat and the water such as is illustrated on the lefthand side of Fig. 3.

Referring now to Fig. 3 it will be noted that due to the outward, upward and rearward motion of the water relative to the bottom of the boat, and particularly when the boat is at speed, the water in passing outwardly, upwardly and rearwardly over the outward edge of the surface 26 will not strike the surface 28 until it reaches a point thereon materially spaced from the jog iii separating these two surfaces and consequently will leave a portion such a 313 of the area of surface 28 free of contact with the water. The size of the area 35 will depend upon the vertical dimension of the jug 40, the angle which the jog Ail makes with the direction of motion of the water, the relative velocity of the water, the degree of V in the bottom of the boat, and the weight, breadth and speed of the boat. 7

This entrance wave in having a relative rearward, upward and outward flow with respect to the bottom of the boat will then flow rearwardly, upwardly and outwardly over the surface 23 until it reaches the next outward jog it separating the surface 28 from the surface 39 at which point it willbreak away from the surface 28 and flow directly outwardly and rearwardly without coming in contact with the surface 30 and consequently willnot wet such surface nor burdenit with its resistance assuming that the surface 30 as repre sentedin this section is above the normal surface of the water over and through which the boat is moving, Consequently, inthe condition assumed in Fig. 3 the only wetted portion of the bottom-of the boat in the section which this figure represents will include only the surface 26 and a part of the surface 28 and the wetted area of the bottom of the boat will, therefore, be materially reduced over the corresponding wetted area of boats having bottoms'of conventional construction.

Referring now to Fig. 4, it is assumed that the outer edge of the bilge 38 at which this section is taken is below the normal surface of the water over and through which the boat is moving. Consequently, the water which is moving relatively outwardly, upwardly and rearwardly is in contact with the fullwidth of the surfac 26 and with a portion of the width of each of the surfaces 28, 30 and 32, which includes the full breadth of the bottom of the boat at this section. The jogs 40, due to air-water. friction and to the relatively rapid lateral movement of water beneath, induce a portion of the air which they are constantly containing into intimate mixture with the boundary layer of water in the form of small bubbles, which action is represented on the lefthand side of Fig. l.

The result of this action is that the boat moves substantially over and through a layer of water containing air in bubble form which offers less resistance to forward motion than water of a normal consistency, It is my theory that this presence of an aerated layer of water for the boat to ride on is one of the reasons why a boat built in accordance with the present invention is capable of'attaining a greater speed than When built in accordance with conventional constructions, power and load being equal.

Referring again to Fig. 2, in th after or rearward regions of the planing surfaces where the water, through and over which the boat is moving, has acquired varying degrees of momentum in the direction of the boats travel, the transverse extent of each area 35 is greatly reduced and in fact at certain speeds and in some portions of the bottom would cease to exist were it not for the lateral surfaces 52 which break adhesion of the water to the vertical surfaces of the jogs 40 and thus effect the induction of additional air from the atmosphere and from the-air in water solution and from that in bubble form and finally, therefore, result in the reestablishment and continued establishment of areas 36 over much of the boats bottom. This is particularly brought out in Fig. 5 wherein the water is shown a flowing in contact with the vertical faces of some of the jogs 40, and being broken from contact with the forward portion of succeeding jog or portion 48 in passing over'the intervening surface 42, forming an air space or pocket 35 in the same manner as the air spaces or pockets 3% previously described. Again, since thetransverse extent of any area 36 is largely dependent upon the relative velocity. of the water coming off of the preceding planing surface at a jog), the lateral surfaces 42 contribute an additional measure to the inducement of areas 36 through their continuing induction of air into. the jogs 4G, with consequent lessened resistance to the relative-flow of water under the bottom and the then 1 resultant higher relative velocity of the water coming off of the planing surfaces 26, 28, 30,32 and 34.

'With further referenceto Fig. 2 and in adtheikeel such as Y following ,a line such as B ::rearwardly. I and. outwardly with. respect to 1 II the; bottom'hfcthe boat; In the construction as: disclosedtr-in United: States Patent: No 2,0 39;586',- I above referred'sto, :thei water .will flow for. a dis-1: tancexin a manner similarit'o that frompoints X r510 in cline A as. described aboveaw- Due; however, to the: above described acqllisitionroffia :degreeof momentum by the: water. in l the "rearward "part I ofthe' boatsbottom; the'water fiowingzas in line: I B will'adhe-re tothe rearward1parts of thewer- 5; ticalsurfaces of dogs :49Jithus destroying 'th'efeffectivene'ss of :Jparts of the. :otherwise unwette'd 1 areas is and greatly-increasingathe"resistance of t the boatto forward motions The efiectwould be still greater in: theflconstruction. shown in the: United lst t rPatent:iNoL ,1,935j622;;fabove'=:ree I fefred to; Due now to the introduction \OfithG offsets 42: 1:11 th'e' present'." invention the: water" flowingas in line B ='Wi 1]'bG fI'GSdEOfaGhESl'On to I and will lose contact-with. the vertic'al 7' surfaces of"jogsl0 ateach-of the offsetsiwith which. it come's in :contact;iaszlillustratedain Fig. :5, thusforcingg due to the atmospheric ihead; the added induction of air into the :emptieduSpace and the consequent f re-establishment: of v unwetted areas" ;:resulting in .a materiall 1 reduced --head-:re--: sistan'ceiof the :boat':

Anotheriimportant-=- result of :vthe above de- Scribe'd -conjoined actions is the i substantial reductionrof the depressant orrweighing-down of 35.. feet of rthe atmospheric headwhich inevitably attempts It wfill .l the trough to the i-rear. "of the entrance rwave by1 pressingor weighing the -boat) I downward' where all previously proposed or con-i ventional smooth-skin-mr non-jogged construc- 40 tions- -lareemployed. It is evident inr the .-.pres.- l ent' invention that-the creation ofair channels l by the introduction of jogsAfll open to theatmosphere and the maintenance of air'passage, throughout their length by: the provision of late eral-.- surfaces 42-a110w free atmospheric access to :much-of the trough. rearward ofthe' entrance: Wave andinso doing relieves thebo'at of much" of the atmospheric headwhich it I would other wise: carryat speed .as added Weight;thus"resulting sin a smaller entrance'iwavev and "conse-' quent smaller trough. and flatter wake; "a posi' tive existence "oflthe entrance"wave"throughout much of the wetted length of the bottom; and I a smaller area of "Wettedsurface" of the hull; the I final :net'" effects being increased" dynamic -sta- I bilityand increased speed as -compared to craft builtin" accordance with conventional *constructions; static displacement andpropulsive power being equal-. 60.

An important" general result -ofthe =construction providedby t-he 'presentinve'ntiong the elim inat-ion of thegreater part of- -th'e bu'rdening: ef: ii fects ofwater adhesion, makes-possible I the. use: of -*distifict1y convex shapes-in the bottomlzportions' of th'e bow an d midship section'sii:resu'lting' i in easier and drien riding an'dv .materially .:-in"- creased speed ianw seaworthine'ss cover? that ob-:- tainedwith boats havings b0tlI0ll1'S' Df"IC0I1VeII-" tional constructions'.-xz

The relati-onl'betwe'en' rth'ei depthi ofizthe" jogs dileand the width :Kof the correspondin -planing surfaces" 26,:28 ;-"30 and 32:01: the equivalent; as a wellias the: number ofssuch:planing-surfaces win: I relation tosthe width of thGbOEltgzIIlEiiY=Va1yrCOIL siderably in different) designsgldepending on v the bottom loadinggspeed-and l other Ifactors of the particular boat 'to which theyare adapted. Likewise, the amountaof lateralaoffsetaof succes-1 sive portions0feach ljog m when each-jog is considered -;-.as extending from a chiner the bilge tox the stern orto the keel; or the rofifset-be-- tween successive'jogs ill-when each is considered" as extending-.- only ubetween the --surfaces--42-and arrangedxin groupsjzaspreviously expl'ained may vary: considerably depending sup on 1 the I f actors I above explained; the relative: angle "between the I jogs liliandrthevkeel, and: otherw'factorsl For in-:. stance; *andw-as. illustrated in Fig. .6, the boat: rhottorn-: 'there: shown is illustrated as zaprovided witha relatively I smaller" number ofrelativelywider-t-plani-n surfaces 25'; 28 and-139%, cor-re-' sponding: to z-the -surfacesi-26;rz28 -andtall of the first described construction, Y said-surfaces being separated from one another by the jogs 4t, cor- I responding 1 to "the --jog=s A9 first describedm Also in this ,=case, the amountuof-off-set rloetwe'en":the: successively :offsetportions of each I :jog; defined 1 by the :laterallytiextending walls ;or surfaces I 42 corresponding t thesurfaces42in: the "first .de scribed-2 construction; f :are 'of much greatenlat- I eral extent: than in the first describedconstrue-:1 tionzz- Suchia constructionmaybefoundiof more advantage in: certain types of I --bo'ats' J: than :the i I relativevarrangementiof -parts ShOWlI' in: Figs: r 1 to.5 inclusive? Referring now to Figs: 5 to'8, inolusivepof them:

drawings rit WlHrbB' noted thatrinzthesenfigures -a E planing type of boat is represented'of-the-stepped type; commonly :used: forf'highspeedtype :of boats II and lmo'difications" of Which 'areV-commonly used-1*: as the :hull component :orracomponents of a flying: "g boat or seapla-ne.- While two.- or-rmorersteps rarer"! frequently zemployed: without departing fromithe" s general type and .fOI'l'i'ifiShOWH, a single-step as? represented-is sufficient -forv-purposes Eof- :cl'escripec tion II and defin iti"on. -.a The boat @shovvn'3:includes" sides -50; 'deck EZ; stern 54 andabottomincludirrg, two major planing-areas;primary"and secondary; indicated generally: as at: SB andi 58;? respeetivelyg: and :se.parated from each other -by:a transverse? step-60; Eachof the majon planing-areasifirand';r 58 closely follows the general-construction'rof thew entire-bottom l6 of -thevboat described" in cone nection' withi-Figs.-1 1305, inclusive; Specifically3 V the -lprimaryplaning area -56 is formedofa series of I smaller planin'g surfaces- 6 2-, 64,-"66, r68; :andi l0? arranged-in compleinentary relationship son; mp .posit-elsidesof 'keel 82 and-of a plahenofrsymmetry; L passing-centrally throughjthekeelyand" extending; diagonallyrancl longitudinally .of the :boat; each of? such planing surfaces: 'bei-ngvseparatecl" 'fromrthei i next-Jadjacentisplaning:surface byamupwardrdog 90,- the verticalsurfaces of: such jogs facing: outi wardly and :indirections towardthe nearer-c bilge and thestern, which jogs -are:interruptedin their" :1 longitudinalcontinuity at intervals; by lateralsurfaces 92 corresponding. tothe'surfaces 12 first described; displacedmowar-d the keel in rearward i progression. VI

Similarly.rthei' -secondary planing: area-58l is formedsof. a series of: smaller planing-surfaces J2;- 14, =16; I8; and arranged-in complementary" relationship on opposite sides of the keel BZ and we of a planelef synunetry-;ipasSing centrallythrough the keel; i and extending diagonallyand longitudi nall-yof :the I boat,--each of such pla-ningzsuriacesv I being'separatedfrom the next adjacent planing; I, sur-taeelby -an upward jog .fifl thevertical surfaces iofz which 'jog yiacing outwardly and indirection's' are interrupted in their longitudinal continuity at.

intervals by lateral surfaces 92 displaced toward the keel in rearward progression.

The bottom of this boat in passing through and over the water effects a reaction as is represented and in the lefthand sides of Figs. 9 and 10, generally similar to that effected by the construction previously described in connection with Figs. 1 to 5, inclusive, in that the water has a relative flow rearwardly and outwardly with respect to the keel, and because of this relative movement it loses contact with the bottom of the boat at each jog 90 and at each lateral surface or notch 92 with which it comes in contact, thus .providing and maintaining through the continual induction of air at speed, an area 86 as represented in Figs. 9 and 10, corresponding to the areas 36 of the first described construction, free of contact with the water.

Likewise the conjoined actions of the jogs 90 and the lateral surfaces 92, which act in the same manner as the surfaces 42 of the first described construction, materially reduce the depressant effect of the atmospheric head which is present in great degree in the operation at speed of conventional planing boats of the smooth-skin type.

In this type of boat as previously mentioned the reaction of the boat with the water when at speed tends to create a region of reduced atmospheric pressure immediately tothe rear of the transverse step 60 and this reduced pressure in attempting to relieve itself tends to draw the water up into contact with the rearward majo planing area 58 at a point much closer to the transverse step 60 than would otherwise be the case, the re sult of such tendency when unchecked being to increase the water adhesion effect and the wetted area of the boat bottom and correspondingly decrease its speed. When the bottom of the boat is constructed in accordance with the present invention sufiicient of the air contained in the jogs 90 is carried rearwardly along the forward major planing area 56 to the region back of the transverse step 60 to largely relieve the low atmospheric pressure at this point, thereby greatly reducing the detrimental effects which would otherwise exist in considerable degree.

The construction described is particularly adaptable for use in connection with flying boats and seaplanes. This is especially true because of the difficulty often encountered in getting such aircraft off of the water in the beginning of a flight. This difficulty arises from the fact that the sum of the weight of the craft and the depressant effect of theatmospheric head taken as weight is often greater than the lifting effort which the wings can exert at the maximum speed of which the craft is capable while in contact with the water. noticed in smooth water conditions, where the existence of a chopwould otherwise allow some degree of atmospheric'access to the wetted portions of the bottom and thus relieve the aircraft of a certain portion of the load imposed by the atmospheric head. In smooth water conditions and in cases where the static displacement vided to the bottom surfaces of the boat, and,

This difficulty is particularly to be,

the consequently great reduction of the atmospheric head depressant, materially lessens the lifting force required of the wings to break the hull loose from the water. Likewise, the substantial reduction of adhesion of the entrance wave water to the bottom of the hull contributes materially to the reduction of wing loading at take-off speed and, in reducing head resistance as previously described, permits a higher waterborne speed to be reached for take-off. Additionally, and as described previously in connection with other applications of the invention, the great reduction of adhesion of the entrance wave water to the bottom of the seaplanes hull permits the use of a more efficient hull conformation having in itself a further reduced head resistance and consequent higher water-borne speed for take-off, as compared to seaplane hulls of conventional construction. Seaplane and flying boat hulls constructed in accordance with the present invention will ordinarily have no trouble in raising off the water, even with a calm surface, with wing and power loadings, and indeed may substantially increase these wing and power loadings without incurring the smooth water take-off limitations of conventional hulls. Another advantage made possible by the present invention through its reduction of entrance wave adhesion is the use of distinctly convex hull conformations of more than ordinary deadrise in the forward and mid parts of the primary planing surface with a consequent material lessening of impact in landing, or setting the aircraft down, on the water and in taxiing and taking off in a rough sea. This is of importance in all water-landing aircraft of whatever size since the magnitude of this impact largely determines the strength and, therefore, the weight and cost of the hull structure required, and is of particular consequence in the present larger, longer seaplane hulls since severe impact in the bow and forward portions of the hull imposes longitudinal stresses which are costly, in terms of weight of structure, to resist.

The application of the present invention to a flying boat hull is illustrated in Figs. 11, 12 and 13 from which it will be noted that the boat hull which is indicated generally at I00 in fragmentary form is provided with two major planing areas I02 and I04, corresponding generally to the planing areas 56 and 58 of the construction shown in Figs. 7 to 10, inclusive, and separated from one another by a transverse step 106 corresponding to the step 60. The planing surfaces I02 and I84, while generally of the same arrangement as shownin the preceding construction, are different in this respect in that preferably in accordance with conventional practice the planes of the two major planing surfaces I02 and HM immediately adjacent step I06 are not disposed in parallel or approximately parallel relation, as are the equivalent planing surfaces illustrated in Fig. '7, but are disposed at an angle with respect to eachother, the plane of the rear section I04 being upwardly inclined with respect to the plane of the forward section I02 adjacent the step I06, at an angle of approximately 12 degrees. This 7 last feature may not be necessary in' all cases but is believed will be of advantage particularly in the larger sizes of flying boat hulls.

Referring particularly to Fig 12 it will be noted that the forward section IE2 is provided with a plurality of planing surfaces I020, I021), I020, IBM, and "Re arranged symmetrically on oppositesides of-a planepf symmetry including the keel of thehullor its equivalentland the" rear section l M i's provided 1 -witltplaning-s'urafaces I Did} I l 041), 4c;-- and. =l'04'd s'imilarly arranged with respect to -such p1anc-. -'-These various planing-survio'usl y idescribed-:-constructions,::and1the:jogs.-: H161- i are'rinterrupte -iby th'e Itransv'erse' rsurfaces': l l 6 '1 corresponding: toitheitransverseasurfaces'm and 92 of the previously sdescribede constructions; vIt

will ibe 'notedithat particdlarly:th'ezrear "end; of therboa't' hull shown in .planoview 'in 'stFig. 12 is 1 not :of the square character ofithestraight marine Whatis claimed is 1. A bo'at' hull of :theplaning type having: sub stanti'ally' the'-entire bo-ttom surface thereof comprised-oi a plural-ity of generally rearwardly. :ex-

tending distin'ct plar'iing surfaces 1 arranged r in compler'nenta'ry: relation-oniopposite sidcs :of the longitudinal plane of asymmetry of said :hullgeach' 2 of: said planing surfaces-being separated: from the next adjacent planing surfacexby a relatively sharp 'jog'cfacin'g generally away from i said planes and said j 'ogs' comprising =por-tions' constituting a fractionof 1 the length thereof offsettoward said 5 ane-ers'ymmetry froni each-other in 'rearwardr progression. 7

2. A boat hull of the planing type havingsub stantially the entire bottom surface thereof comty'pese of=izconstructionswrshown Yin the-preceding views but is rounded offz 'this .'-being in accordanc'e -twith conventional? flying hoat' hull practice and inr: orderto'i-providerthe" streamlined effect necessary: to lower the: dragcthereof -"in'moving throughythe airs? Thesection shown in Fig. -l3 does=-not illustrate I thin-metal suitably :forme'd to-.-shape.- Likewise ink-thesection -shown in Fig.- 13 it will be appre ciatedrthat the jogs-.--l 081-are notprovidedwith-r a square -inner= corner: assin the precedingviewswhere wooden planking is shown, the same being":-

shown 'rounded' orradiused' inFig:13: -'-Wherethe bottom is formed from metal and where two or more planing surfaces are formed from the same sheet of metal, it will ordinarily facilitate construction to provide such rounded corners as shown. The essential feature is that the lower edges of the jogs Hi8, and the outer edges of the surfaces I Ill, or their equivalent, be sharp as these are the edges which control the breaking away of the water from the cooperating planing and jog surfaces, respectively.

In the application of the present invention to flying boat hulls it will be appreciated that as the flying boat picks up speed on the water the bottom loading, or effective weight of the hull on the water, decreases and as the effective weight de creases and the hull rises relatively with respect to the water the area of wetted surface of the bottom of the hull decreases, contrary to the smooth skin conventional constructions, the drag of the hull in the water thus being materially reduced as the speed of the seaplane increases and consequently its effective weight upon the Water decreases. This in itself reduces the adhesion between the boat hull and the water to a great extent and, taken in conjunction with the flow of air along the jogs I08 relieving the atmospheric head tending to hold the boat on the water, results in a construction of vastly superior characteristics from a take-off standpoint.

Although I have shown but three specific examples of the present invention in connection with the drawings, it will be apparent that the prisedare; plurality"offlgenerally rearwardly ex 1- tending distinct planing: surfaces :arranged in comple'iiienta'ry relation onopposit'e sides of the longitudinalplaneof symmetry-of s'aidiliullpeacha of -said. pianingzsurfaces bein-gzseparatedrtromithe nextadja'cent planing surface byJa relatively'sharp "cing generally=iaway:..fromcsaidlplanerand' ogs';comprising:portionssconstitutinga f-rao tion'iof theilen'gthithereofaoffset towardsaidrplane' of 'symmetry fronneachbther'in'rearward progress sion; eachof-saidqiortidhs terminatihgaatits rear= r mosteendi infra relatively ifsharp edge.

3. A boatnhull 'of the planing:- type havingsub at stantially the entire bottom isurfaceuthereof :com-- prised ofa plurality of'rearwardly ext'ending distinctoplaningFsurtaces arrangedrincomplementary relation 'orropposite sides of .the longitudinalzplanev ofvsymmetry of said hull: andin?" rearwardly con-r verging relationship with respect to said plane, each of said planing surfaces being separated from the next adjacent planing surface by a relatively sharp jog facing generally away from said plane, and said jogs comprising portions constituting a fraction of the length thereof offset toward said plane of symmetry from each other in rearward progression, each of said portions terminating at its rearmost end in a relatively sharp edge.

4. A boat of the planing type having substantially the entire bottom surface thereof comprised of a plurality of diagonally and longitudinally extending distinct planing surfaces arranged in complementary relation on opposite sides of the longitudinal plane of symmetry of said boat, the medial lines of said planing surfaces increasing in angularity with said plane of symmetry successively rearwardly, each of said planing surfaces being separated from the next adjacent planing surface by a relatively sharp outwardly and rearwardly facing jog, and said jogs comprising a plurality of longitudinally distinct portions offset in rearward progression toward said plane of symmetry.

5. A boat hull of the planing type having substantially the entire bottom surface thereof comprised of a plurality of genenally rearwardly extending distinct surfaces arranged in complementary relation on opposite sides of the longitudinal plane of symmetry of said hull, each of said planteachings herein will be sufficient to permit one skilled in the art to adapt the inventive thought to like devices of different types of construction, and, accordingly, it is to be understood that formal changes may be made in the specific embodiments of the invention described without departing from the spirit or substance of the broad invention,

' the scope of which is commensurate with the appended claims.

6. A boat hull of the planing type having substantially the entire bottom surface thereof comprised of a plurality of generally rearwardly extending, distinct planing surfaces arranged in complementary relation on opposite sides of the longitudinal plane of symmetry of said hull, each of said planing surfaces being separated from the next adjacent planing surface by a relatively sharp jog facing generally away from said plane, said jogs comprising portions constituting a fraction of the length thereof offset toward said plane of symmetry from each other in rearward progression, and each of said jogs tapering in depth from a maximum in its central portions to minimal at its rearward end.

7. A 'boat hull of the planing type having substantially the entire bottom surface thereof comprised of a plurality of generally rearwardly extending distinct planing surfaces arranged in complementary relation on opposite sides of the longitudinal plane of symmetry of said hull,-each of said planing surfaces being separated from the next adjacent planing surface by a relatively sharp jog facing generally away from said plane, said jogs comprising portions constituting a, fraction of the length thereof offset toward said plane of symmetry from each other in rearward progression, and each of said jogs tapering in depth from a maximum in its central portion to minimal at its forward end.

8. A boat hull of the planing type having substantially the entire bottom thereof formed of 'a plurality of longitudinally separate major planing areas separated from each other in rearward progression by a vertical step, each of said major planing areas comprised of a multiplicity of generally rearwardly extending distinct planing surfaces larranged in complementary relation on opposite sides of the longitudinal plane of symmetry of said boat hull, each of said planing surfaces lbeing separated from the next adjacent planing surface by a relatively sharp jog facing generally away from said plane, and said jogs comprising portions constituting a fraction of the length thereof offset toward said plane of symmetry from each other in rearward progression.

9. A boat hull of the planing type having substantially the entire bottom thereof formed of a plurality of longitudinally separate major planing areas separated from each other in rearward progression by a vertical step, each of said major planing areas being directed upwardly from such step, from which it rearwardly extends, with respect to the general plane of the preceding major planing area in the region of such step, each of said major planing'areas comprised of a multiplicity of generally rearwardly extending distinct planing surfaces arranged in complementary relation on opposite sides of the longitudinal plane of symmetry of said boat hull, each of said planing surfaces being separated from the next adj acent planing surface by :a relatively sharp jog facing generally away from said plane, and said jog-s comprising portions constituting a fraction of the length thereof offset toward said plane of symmetry from each other in rearward progression.

CHARLES DOUGLAS VAN PATTEN.

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