US1877380A - Marine craft - Google Patents

Description

Sept. 13, 1932. E. E. BALDWIN MARINE CRAFT Originl Filed Nov. 12. 1929 5 Sheets-Shet 1 INVEN O I I I ATTORNEY P 13, -7 E. E. BALDWIN v MARINE CRAFT Original Filed Nov. 12. 1929 5 Sheets-Sheet 2- ATTORNEY I B 8g Agnew-:21 G u.

Sept. 13, 1932. BALDWlN 1,877,380

- MARINE CRAFT Original Filed Nov. 12.- 1929 5 Sheets-Sheet 3 ATTORN EY Sept. 13, I932.

E. E. BALDWIN MARINE CRAFT 5 Sheets-Sheet 4 Original Filed Nov. 12. 1929 ATTORNEY Sept. 13, 1932.

E. E. BALDWIN MARINE CRAFT Original Filed Nov. 12. 1929 s sheetsrsne et 5 ATTORNEY Patented Sept. 13, 1932 PATENT OFFICE.

EDWARD E. BALDWIN, OF NEW YORK, N. Y. I

MARINE CRAFT Application filed November 12, 1929, Serial No. 406,604. Renewed January 29, 1932.

This invention relates to marine craft, and

boats; some of the objects being to increase the efliciency of the power expended, there- L by increasing the speed; the reduction of turbulence in the liquid and the elimination of hammer blows on the hull bottom; the reduction of friction or adhesion of water to the hull bottom; the reduction of head wind pressure, while increasing the stability of the hull and the manageability by the ease with which the craft holds a straight course; and the elimination-of side Wake and spray; all 5 being desirable results for the general improvemeiit of commercial and pleasure craft.

In seeking to attain these objects successfully, my invention makes use of a hull, having a stream line upper body and a bottomv system of planing surfaces, which are so ar-' ranged that while being a type of stream line formation in themselves, their action on the fluids as the craft moves forward, sets up a reverse secondary stream line formation in the fluids or liquid over which the hull rides; with a resulting decrease in. turbulence, friction, side wake, spray, etc, of the fluids on the hull bottom. so The invention is primarily predicated moreover on the novel idea of using advantageously the head wind pressure, effectively diverting the direction ofthis wind pressure to a point between the exterior bottom surfaces of the hull and the water thereunder.

This air stream interposed under the hull body becomes part of the secondary fluid streamline formation set up by the aforesaid arrangement of planing surfaces, while 4 -";-sorbing the turbulence of water against the hull bottom, and converts this turbulence into skin friction. Also areduction in friction is obtained by substituting an air surface for water surface'on the hull bottom, the air secondary fluid streamline formation of the combined fluid over which the hull moves, a great amount of the commotion, or turbulence, caused in the water by the hydroplane typeof hull is avoided. The side wake,.or

lubricating the hull bottom. Owing to the:

back drag, is entirely eliminated by the above methods of construction.

I'have found in actual experiments that the following construction is effective. A hull streamlined above the freeboard; and, placed forward in the hullsurface, an opening leading to an air chamber within the bow of the hull to provide an entrance and a containing means for head wind pressure, the aforesaid opening combined with shutters as a means for graduating the quantity of air entering the chamber. Means are used for controlling said air in the chamber consisting of a conoidal wheel revolving in a plenum chamber, with exit means on the hull bottom in the form of a step outlet, which step divides the bottom planing surfaces into forward and aft sections. The forward section has a central cutwater with concave surfaces to edges of the hull sides. These edges joining the sides of the hull are lower than the apex of the concavities, as a meansof directing a current flow inwardly, toward the apex of concavity, and outwardly from the cutwater.

The concave surfaces spiral downwardly in a graduated radius of curvature to the terminus of the planing angles. The concavity of the surfaces also is graduated, diminish ing towards the terminus of the planing an gles, therefore the planing surfaces act as channels for directing the fluid and liquid in a current stream under the hull bottom, The terminus of the planing angles become the flat lower surface of the step, or air outlet means. The aft planing surfaces extend from the vertical side of the step to the stern and are formed in two surfaces with the apex of the angle at the keel line of the hull and the outer edges joining the sides of the hull level with the lowest side of the step. Therefore, aft of the step, when the hull moves forward, a four sided pocket or suction space is formed. The vertical side of the step is to a great extent open to allow air to enter into the suction pocket. Two sides are formed by the =inverted V of the angularly placed planing surfaces and the lower or fourth sideis formed by the liquid. The aforesaid pocket i'sa means to facilitate the hull in attaining a position in the Water offering the least resistance to its forward progress, owing to the buoyancy, or lifting power, of the air; and the pocket is a suction space to facilitate the air means within the hull in delivering the air through the step into the pocket and between the exterior surfaces of the hull bottom' and water thereunder and without destroying the current flow of either fluid or liquid.

The apex of the inverted V of the aforesaid aft planing surfaces extends to the stern of the hull, said angle conveying the air in a steam formation from step to its discharge from under the hull directly aft of the stern as wake. The aforesaid inverted V type planing surfaces are graduated from step to stern and the angle is more acute towards the stern with the apex of said angle at the keel line of the hull and tilting upwardly towards the stern; and the edges of the surfaces join the sides of the hull level with the bottom of the step air exit opening. As the craft moves forward in the water which contacts the outer portion of the angular surfaces adjacent to the air stream, a current flow is caused in the water with a tendency to. glance towards the air stream, the tendency increasing towards the stern of the hull bottom.

Thewater owing to the glancing inward motion is turned in one direction and the hull does not hit the water a direct blow and scatter it in all directions; thereby the passage of the hull through the water causes a minimum of turbulence and no side wake and spray. The water glancing inwardly meets the air stream which further reduces the turbulence against the hull bottom by absorbing and cushioning the hull bottom.

The combined surfaces of the inverted V type bottom direct the current flow in the combined fluids into a stream formation or secondary fluid streamline formation harmonious in line to the hull formation, thereby reducing turbulence into skin friction on the hull bottom; the skin friction is further reduced by substitution of air surface for water surface. All of the wake is discharged from underneath the hull directly aft of the stern, and disregarding the action of the propeller on the water, is the tail or concave trailing edges of a fluid streamline body. This wake rapidly disappears as it is white water heavily charged with air.

While I have carefully described certain successful embodiments of the main features of my invention, I wish it distinctly understood that what I have presented is only a specimen or example of the many' forms which the invention mi ht assume, and I do not wish to be restricted to the precise form or the examples herein offered, because the configuration and features combined there:

with may be greatly modified without depart ing from the invention claimed.

In the accompanying drawings illustrating my invention:

Figure 1 is a top plan view of my improved marine craft.

Figure 2 is a side elevation of the same.

Figure 3 is a longitudinal central section of the same.

Figure 4 is a bottom plan view, delineating the action of the currents of air and water.

Figure 5 is a similar bottom plan view, delineating more particularly the shape of the bottom of the hull.

Figure 6 is a partial or fragmentary side elevation at the front end.

Figure 7 is a rear end elevation.

Figure 8 is a front elevation of the same.

Figure 9 is a cross section on the line 9, 9,

of Figure 3.

Figure 10 is a cross section on the line 10, 10, of Figure 3.

Figures 11 and 12 are diagrammatic views indicating the shape of the front concave re cesses in the bottom of the bow of the hull from the front end back as far as the air outlet opening.

Figures 13 and 14 are similar diagrammatic views indicating the shape of the inverted V-bottom of the hull from the air outlet to the stern.

Figure 15 is a fragmentary perspective of the bow portion of the boat, somewhat diagrammatically expressed.

Figure 16 is a small plan view'of my improved form of boats in outline to indicate the streamline action of the boat in the water in forming a straight wake at the stern.

Figure 17 is a similar plan view in outline of the common form of boat with a pointed bow and the usual hull that creates lateral turbulent areas to obstruct its progress, this being shown in contrast with my improved construction indicated in Figure 16.

Similar characters of reference designate corresponding parts in all the different figures of the drawings.

1 denotes the hull of any type of marine vessel, given as an illustrative specimen only, the shape of which hull may obviously vary within wide limits. The particular-example of hull shown is that of a modern high speed motorboat. The hull 1 is a streamlined hull above the freeboard, to reduce wind resistance, and is preferably fashioned on its upper longitudinal surface with narrow sections la that curve downwardly at the bow into the blunt nose 2, such sectional surface being similar in appearance to certain kinds of streamlined dirigible air ships, but obviously this construction may be altered as desired.

7 denotes the rumble or pit, wherein is one or more seats at 8, or a cabin structure may be provided instead if preferred. 9 denotes an engine or motor; 10 a shaft driven by said engine and carrying a bladed propeller 11, be-

sides being forwardly connected to actuate a fan mechanism 12; 13 the rudder or rudders; and 14 a steering wheel to control the position of the rudder through suitable cables or other connections.

All these features may be arranged in connection with the hull and related to each other in position and function in the most convenient and approved manner, and I do not wish to be restricted to any precise plans. Also the steering wheel 14 is adjacent to the instrument board or dash in pit 7, which may carry all the usual or desired indicators, gauges, pointers, and other devices and controls.

.In order to more fully contrast the per formance of my improved contour of hull with old and well known forms, I have indi cated my improved boat at A in Figure 16, and the boat commonly in use today at A in Fi ure 17. The boat A creates the lateral elds of foam, turbulent agitation or side wakein the liquid known as back drag and hammer blows and which take power to produce, thereby causing loss of speed. My improved boat A, with its novel arrangement of bottom planing surfaces and air cushioning and absorbing process, first reduces the size of the turbulent field of water to that surface directly underneath the hull bottom, thereby eliminating all side wake or spray; second, 'the turbulence in the liquid is converted into skin friction by the com bined action of the planing surfaces of the hull bottom and the air stream, thereby eliminating hammer blows and back drag to a great extent; third, reducing the friction to a minimum by substituting air for water on the hull bottom; fourth, by directing the current flow in one direction or the formation of a secondary fluid streamline under the hull bottom harmonious in line to the hull and its forward motion, thereby reducing the adhesive grip of the combined fluids to the hull bottom to an absolute minimum, thus allowing boat A to steadily and smoothly ride forward and increasing the efiiciency of the power expended.

The reason of the difference and argument for what I accomplish will'appear as I proceed. a

The two concave surfaces 5 on opposite sides of the cutwater 3 spiral downwardly with a graduated radius of curvature, the concavity diminishing toward the terminus of the planing angle, at the flat bottom 4 or lower surface of the air outlet 23. Viewing the front end of the bow we see nose 2 above cutwater 3 and the curved concave surfaces 5. See Figure 8. From nose 2 the edges 2a of the boat curve around as seen in plan View in Figure 1. The bottom edges of side sections 2a curve downwardly until they merge into the bottom edges 26 of the aft planing surfaces 25. As seen in Figure 8 the concave surfaces 5 are graduated with a radius of curvature as they recede from nose 2 to the flat bottom 4 below outlet 23, at the terminus of the planing angle. The changing shape of the different sections of the concave surfaces 5 isbrought out in the diagrams in Figures 11 and 12, which indicate the sectional curves at various points. Thus in Figure 12 the dotted curves indicate the shape of the concavities 5 at the extreme front,as viewed in Figure 8. Various points in the length of the concave channels have been selected and indicated by the vertical lines 6, f, g, and h; and from the points where these lines intersect the curved surfaces of the channels 5 I have drawn horizontal lines respectively, as lines e f 9 and k These lines in Figure 12 show the position of curves e f 9 and k which represent the cross sections of the concave showing the relative graduation of curvature at the points out by the vertical lines.

In this diagrammatic way I show that the rather sharp curve at the extreme front gradually merges into section after section of lesser curvature until the flat horizontal section 4 is reached, at the terminus of the planing an 1e. This is only one example, and given y way of illustration merely, since the concave surfaces may vary widely in shape, as also in'number, for there may be one or several of them curved out or in or longitudinally or otherwise.

In the front portion of the how 2 is an air chamber 16, one or more, with a front opening 6, or window, which is equipped with a series of pivoted shutters 17 operated by a connection 18 provided with a handle 19 at the instrument board 15. Thus we have'an air chamber which is largest at the front end of the bow where the opening 6 furnishes an air outlet controlled by the cover composed of shutters 17, which may be opened more or less at will. The inner smaller end 20 of the chamber 16 communicates with the fan chamber or casing 21 which has a curved lower end 22 at the bottom of the hull which is formed with an air delivery mouth 23, that is thin and wide and preferably in the form of a step as it were and the bottom of the hull and into the inverted V type channel as indicated by arrows F, F, formed by the after planing surfaces, while the water, with the.

forward movement of the hull glances or grazes the under side 4 of the air outlet at 23.

However, I do not wish to be confined to an outlet step. It is preferable and has been found eflicient but the air outlet as well as the air inlet may obviously be widely varied. The air travels around the hull, top, bottom and sides. vary widely and still retain the efficiencyof a streamline hull. The air intake in the bow may be through one or several openings, to

The streamlines of the hull may allow the head wind pressure at the bow or point of greatest resistance to the forward movement of the hull, to flow or be absorbed into the air chamber and through the fan, if one is used, to be passed through the exit opening on the bottom of the hull in large enough quantities to form a stream of airv a percentage of the water under the hull.

The deflection of the air may be accomplished in a variety of ways. Pressure through the opening in the bottom of the hull may be regulated and controlled by means of a variety of air compression or blower devices, such as blower or compression fan wheels, or other types of compression devices. The type of fan wheel at 12 is of the blade type revolving ina plenum chamber.

The air deflected under the hull has a lifting action, as well as functioning as a lubricant to reduce friction and turbulence of liquid on the hull bottom. It is a most important feature of my invention that air or fluid pressure taken in through an opening in the hull of the boat and following through an opening in the water side of the hull adds buoyancy to the hull in motion and exerts a lifting power, which aids the hull in quickly and easily attaining a planing positlon or position in the liquid, offering the least resistance to its forward motion through fluid and liquid. The central portion of the air surface deflected downwardly joins the surface of the water underneath the hull. See Figure 4.

If air pressure were thus used only to help the hull to rise to a planing position on the water, this could be done without involving the other principles of the invention, in regard to the location and kind of intake, the placing of an air compression unit and dif ferent kinds and shapes of air exit openings, all of which the water surface serves as a seal. The boat I have shownand described is a type of construction that has both buoyand a continuous flow of air under the The bow from the nose 2 to the air outlet 23 is partially in the water when the hull is stationary. When the hull moves forward, the concave planes 5 on either side of tho cutwater 3, with the air of the lifting power, or buoyancy, of the air stream underneath the hull bottom, cause the hull to attain a planing position, or position in the fluid and liquid offering the least resistance to its forward progress, owing to the tendency of the current flow in the fluid and liquid to move outwardly from the central outwater 3 and inwardly from the edges of the above surface 4 on line a, a. The air under concavities of planing surfaces 5 toward line the concave bow planing surfaces meets the water at this point and forms a surface of charged water, which adds itself to and forms j the underseal to the air stream'formation under the hull body from the air exit to stern.

The under surface of the hull may have a. variety of forms of a channel designed to keep the air under the hull, the water being used as a seal for the air under the hull, the sides of the channel or channels being so arranged that the air is delivered from the air exit on the bottom of the hull in a stream formation toward the stern and out from underneath the hull directly aft of the stern.

The channel is angular, its central side being determined in relation to the planing angle of forward surfaces, size of air exit on the hull bottom, lifting capacity of air under this hull, weight of motive power, so that the point of least resistance to the exit of air from underneath the hull is directly aft of the stern.

The aft bottom surfaces of the hull are so arranged that while being a type of stream line surface in itself directs the current flow of fluid and liquid into a secondary fluid stream line formation, also converting turbulence in the liquid into skin friction. The aft planing surfaces extending from the air exit to the stern, are angularly set surfaces of the inverted V type bottom, the angle of the inverted V var ing from the air exit to the stern, it being atter and more obtruse where it receives the air and sharper and more acute at the stern where it discharges the air, and the flat sides of surfaces of this angular channel being inclined from one end to the other, which inclination will have the rear end highest when the hull is at rest, but will assume an approximately horizontal position when the hull is moving forward has attained a full planing position, to correspond with water line a, a, in Figures 2 and 3.

The flat surfaces 25 of this inverted V shaped or angular channel 24 have outer edges 26, 26, which are the bottom edges of the sides of the hull, and these edges are level with the lower side of the air exit 4.

The graduation in angle from air exit to stern is accomplished by tilting the apex of the angle of the surfaces. With the forward movement of the hull, water contacts with the aforesaid surfaces from the edges 26 inwardly towards the air stream, as indicated at X, Figure 10, by arrows, sealing in the air stream. The upward and inward inclination of the angular surfaces of the inverted V forming a surface, while directing the current flow in fluid and liquid longitudinally with the hull. The tendency of the liquid stream is to glance inwardly, which tendency increases as the angle of the surfaces becomes more acute toward the stern from edges 26, 26, towards the central air stream and the surfaces opposed to the liquid being angularly placed, cause the liquid to glance on rather than strike directly at said surfaces, the air stream absorbing or dispersing said turbulence and converting the latter into skin friction, thereby eliminating turbulence or hammer blows and back drag on the hull.

The graduated increase in the acuteness of angle of the planing surfaces from the air outlet to stern forms an angular surface so graduated that with the forward motion of the hull the action of the combined lateral (at G, G, Figure 7) and longitudinal angles of the planing surfaces and the air stream, in which latter the current flow is directed mechanically, and causes the liquid to join and become part of this general stream formation causing the combined mass of liquid and fluid under the hull bottom to become a fluid streamline formation with lines harmonious to the lines of the hull.

This harmony of line established between hull formation and the surface over which it rides, the turbulence or eddy flow in the liquid having been absorbed or dispersed by the lighter fluid mass of air,'reduces friction on the hull bottom to an absolute minimum, and as the greater part of this efliciency is gained without the aid of motive power, a decided increase in the efiiciency of power expended'is the result.

Generally speaking, a streamlined body is one shaped to prevent turbulence in the fluid through which it passes and directly aft in its wake. The bottom surfaces of the hull area streamline formation, but so formed that a reverse or secondary fluid streamline formation is caused in the fluid and liquid .over which the aforesaid surfaces ride. The wake is discharged from underneath the hull directly aft of the stern, and disregarding the action of the propeller on the liquid. The wake becomes the concave trailing edges or tail of the fluid streamline mass, rapidly disappearing as the liquid is heavily charged 7 with. air.

The air exit at 23 discharges air into the V-channel which is shallow at that point and whose centre line is at 24. This channel varies in its angle from the outlet 23 where it is quite flat and obtuse to the rear end where it is more acute. This has been plotted in a general diagrammatic way in Figures 13 and 14, so as to show the variation in the angles. The vertical lines 6, 0, and (Z, intersect the bottom of the hull, and from the intersecting points run respectively the horizontal lines 6 0 and d, which in Figure 14 meet the angle line and show how the planes vary in their angular relation to each other from end to end at the inverted V'-channel. In this way the channel has a streamlined formation. The degrees of the different angular lines are indicated at b", 0 and d in Figure 14.

I seek to utilize and extend this harmony of motion or streamline principle in my hull construction and to add the advantages thereof to the other features of my improvement.

What I claim is:

1. In marine craft, a hull, the bottom of which is provided with a cutwater and forward concave planing surfaces at opposite sides of the cutwater, and aft planing surfaces forming an angular channel of inverted V type, the angle of the channel being graduated in acuteness from end to end, in combination with means within the hull for receiving air pressure as the craft moves forward, and means having an outlet for delivering air into said channel under the hull, and said channel directing the current flow in fluid and liquid with a secondary fluid streamline formation.

2. In marine craft, a hull streamlined above the free-board, the bottom of which has a forward concave planing surface graduated from a concave at the nose of the bow to flat at the terminus of the planing angle on the hull bottom, aft planing surfaces extending from the terminus of said angle to the stern, which latter is formed with angularly set surfaces of inverted V-type graduating from flat at the aforesaid terminus of the planing angle to acute at the stern, and means within the hull for receiving and controllin fluid pressure and delivering it into said 0 annel at a point contiguous to the flat bottom section.

3. In marine craft, a hull streamlined above the free-board the bottom of which is formed with a forward concave planing surface, concave at the nose of the how, the concavity decreasing gradually toward the terminus of the planmg angle from terminus of angle aft to the stern, angularl set surfaces of inverted V type channel ormation graduating from obtuse at said terminus to acute at the stern to direct a current flow in fluid and liquid, as the craft moves forward longitudinally under the hull bottom so that all the wake is delivered from under the hull directly aft to the stem.

4. In marine craft, a hull, the bottom of which is divided into forward and aft plan-- ing surfaces, the latter surfaces extending from the terminus of the forward secton to the stern in a channel formation, said chan nel graduating from shallow at said terminus to deep at the stern, a means to cause the liquid to glance on said surface from side towards center of said channel while, with the forward movement of the hull, directing the current flow of liquid longitudinally under the hull bottom, as meansto reduce turbulence in the liquid and convert the latter into skin friction.

5. In marine craft, a hull, the bottom of which is divided laterally by a step into forward and aft planing surfaces, combined with means within the hull for receiving head wind pressure and delivering and controlling same through exit means located in the vertical side of said step, the forward planing section having a cutwater on opposite sides of which with a spiralling graduated radius of curvature the surfaces extend to the edges of the hull sides, in a channel formation, the outer edges of the channels being lower than the center of the channels, the curvature of said channels extending from the nose of the craft downwardly to the terminus of the planing angle, the lateral concavity of said channels diminishing toward terminus of said angle into the approximately flat bottom of said step, as means to direct the current flow of fluid and liquid longitudinally with said channels and under the bottom of said step as a seal to air delivered from head Wind pressure to the aft planing surfaces.

6. In marine craft, a streamlined hull above the freeboard, means within the hull for receiving head wind pressure as the craft moves forward, means for regulating quantity of air entering receivlng means, means for increasing and diminishing a pressure in said receiving means, means for delivering said air pressure to the exterior bottom surface of the hull, which latter surfaces are a type of streamline formation, so placed that an inverted channel is formed on the hull bottom, the graduation laterally and longitudinally of said surface sloping to form said channel that with the forward movement of the hull a current will flow longitudinally sternward is caused in fluid stream and liquid in a secondary streamline formation harmonious in line to the aforesaid bottom surfaces, as means to convert turbulence in the liquid into skin friction and further reduce said friction by the harmony of motion established between the hull and fluid and liquid surface over which it rides.

7. In marine craft, a hull, the bottom of which is divided into forward and aft sections by a step, in combination with means within the hull for receiving head wind pressure and discharging same through air exit means in the vertical side of said step, the aft bottom section forming an inverted channel, the lateralangle having its apex at the keel line of the hull and they edges joining the sides of the hull level with the bottom of the aforesaid step, the longitudinal angle tilting upwardly on the keel line of the hull from step to stern, causing the lateral angle to be obtuse at 'the step and graduating to more acute at the stern, said combination of angularly arranged surfaces, as means for holding the air current derived from means within the hull to a stream foundation from step to stern while the said lateral angle of surfaces causes an angularinward pressure on the liquid surface and the turbulence, hammer blows and eddy motion in the liquid caused by the forward momentum of the hull glance inwardly on said surface to be absorbed and'disintegrated by the air stream, the combined mass of fluid and liquid being formed by the longitudinal angle of said surfaces with a current fiowlongitudinally with the channel towards the stern, theincrease in acuteness of angular surfaces toward the stern forming a graduated increase in angular pressure exerted on said fluid and liquid, as means to cause the aforesaid current flow to form a secondary fluid streamline formation, thereby eliminating side wake and turbulence in fluid and liquid aft, and delivering the fluid and liquid from under the hull directly aft of the stern, this wake form-' ing the tail of the fluid streamline formation.

8. In marine craft, a hull with streamlined free-board, the bottom of which from the stern forward is an inverted channel, the

apex of which is higher than the hull bottom adjacent to the forward terminus, the sides extending downwardly from the apex to the edges of the channel, said edges being continuous with the hull forward of the channel terminus, said channel being in combination with means within the hull for receiving fluid and delivering fluid under pressure into said channel, which is graduated laterally and longitudinally to directthe current flow of fluid and liquid, with the forward motion of the hull, into a secondary streamline formation, coordinating in motion with the fluid stream passing over the freeboard surface of the bull to serve as means to economically convert turbulent drag into viscousor skin friction and establish a harmony of motion between the fluid and the liquid in which the craft is immersed.

9. In marine craft, a hull, the bottom of which is an inverted channel with right tom and continuing to the stern with keel line continuing to the stern above the chines, with the angle of the chines in relation to the keel expanding to the stern and forming a right and left laterally and longitudinally graduated planing surface on opposite sides ofthe keel, with the craft at full planing angles and chines depressed downwardly at the stern, but with the keel line substantially parallel to the water surface at the stern, forming a central channel unobstructed by the depression of the hull at the stern due to planing with two longitudinal suspension areas determined at the chines, the whole serving as means to lubricate the hull by a mixture of air and water under the hull bottom due to velocity head pressure having passed the point of critical velocity and to form a fluid and liquid stream line formation longitudinally harmonius in line with the inverted channel, with velocity head pressure forming the center and moving fastest, the wake forming the concave trailing edges,

the discharge being directly aft of the stern.

10. In marine craft, a hull, combined with air means within the hull having inlet and outlet means, the latter in connection with forward and aft planing surfaces of the hull bottom, the latter forming an inverted channel from saidoutlet means to the stern, the right and left sides from the chines to the keel being of longitudinally similar dimensignature.

EDWARD E. BALDWIN.

sions, the longitudinal angle of the chines in I relation to the keel line expanding to the stern, the aforesaid air means developing suction forward and static head pressure in said outlet means, said static pressure being converted into velocity head pressure at the forward enol ofsaid channel with the point of least resistance to its discharge longitudinally central with the channel at the stern, as means to propel the craft forward while forming fluid and liquid into a stream line formation, all the wake being delivered directly aft of the stern.

'11. In marine craft, a hull, the bottom of which has forwardand aft planing surfaces formed with right and left sections from chines to keel and longitudinally continuous and of similar dimensions, the forward planing surfaces extending from the nose with chines joined at the keel to form the forward leading edge, and extending downwardly and expanding laterally to the width of the hull bottom, the keel continuing to the stern above the chines, the aft planing surfaces being in inverted channel form, the longitudinal angle of the'chincs in relation to the keel expanding to the stern. combined with means located in the forward end of said channel for dischargin: fluid and gases under pressure, caused by the operation of means within the hull, and directing the velocity longitudinally within the channel to the stern and forming the fluid. liquids, and gases into a stream line formation, all the wake being delivered directly aft of the stern and as means to propel the craft forward.

12. In marine craft-,a hull, the bottom of which is divided into rightand left sections longitudinally of similar dimensions,

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