HIGH STRENGTH, HIGH SAFETY SUBMERSIBLE VESSEL

Abstract: A submersible or submarine vessel (10) having a unique pressure hull formed from a plurality of truncated generally spherical cells (16) lying in a common plane and having at least one opening (22), wherein the cells are connected together preferably in a generally loop array with the cell openings (22) in confronting relation to define an interconnected internal space for utilization by personnel, equipment, or machinery. When the connected cells define a loop array having an open central area, a dome (40) encloses the central area permitting utilization thereof, or, a further spherical cell or cells are disposed in the central area (28) with access thereinto from a cell in the loop array for utilization, whereby at all times convexly curved spherical surfaces are exposed to high hydrostatic pressures, thereby to provide a maximum strength pressure hull. An external generally flattened hydrodynamic hull (12) encloses and is braced to the pressure hull, and which is not subjected to significant water pressure differentials on either side thereof.

Description: HIGH STRENGTH, HIGH SAFETY SUBMERSIBLE VESSEL Background of the Invention Throughout the long history of submersible and submarine vessels a chief design and structural goal has been to provide a submarine or other underwater vessel having the capability of withstanding extreme external underwater pressure, which is directly related to functional depth operations, and also to be capable of maintaining structural integrity during rapid pressure changes due to necessary or accidental transitions of depth. Collateral thereto is the necessity of ensuring safety to the occupants or crew within the submersible, and more particularly in the pressure hull thereof by virtue of the pressure hull strength, while yet providing a relative maximum amount of volume area for workspace and equipment space therein. In comparable manner, a submersible or submarine vessel must be capable of maximum speed of travel through the sea by virtue of streamline form, while yet maintaining high structural rigidity. Development over many years, including the intense active engagements in two World Wars, have largely resulted in the development of submersibles and submarines having pressure hull configurations essentially of cylindrical or cigar-like form, having an external hydrodynamic form streamlined to suit surface operation, thus evolving an elongated, essentially linear, internal volume for habitation and machinery compartmentation, utilizing the inherent hoop strength of a small diameter and circular cross-section to adequately resist depth pressure. While this form has been and is universally employed for submarine form, the same are more suited for withstanding internal pressures, in an engineering sense, than an external hull collapsing pressure, the latter of which is a principal area of concern in submersibles and submarines. Further advancements toward high underwater speeds and nuclear propulsion created the need for larger displacement hulls, significantly increasing the cylindrical hull diameters, and demanding the use of exotic and costly metallurgy to achieve the required hull strength, with attendant large increases in fabrication costs. This developmental change in submarines resulted in redefining the hydrodynamic form to suit a fully underwater operation, and introducing large single hull construction and shifting variable ballast systems away from amidships. The demand for increased size has extended the overall hull length beyond the generally accepted length over diameter ration of six-to-one. The diameter is restricted by the draft limitations of harbors, and the increased structural requirements for enlarged diameter hulls. This ratio has proved unattainable throughout the twentieth century. The need to limit growth in the vertical profile has in some instances required designers to employ two parallel laterally adjacent cylindrical pressure hulls to accommodate larger displacement, thereby shortening hull length and draft, and avoiding excessive wetted surfaces. Despite such efforts, the factors of limited depth capability and very high cost of construction are not alleviated. Further, the general cylindrical form of the pressure hull is not materially altered, even into very recent times. See, illustratively, the discussions of submarine design in Marine Technology. "SEAWOLF Design for Modular Construction", October, 1992 commencing at p. 199. It is noted, for example, that bulkheads in the SEAWOLF class submarines have diameters on the order of 40 feet, and an area of some 1,256 square feet each, with resultant serious and expensive fabrication and pressure resistance problems to be overcome in building the hull. There is manifestly indicated a need for a pressure hull design that is far more structurally efficient, significantly less costly, and yet satisfy the volumetric demands of modern submarines. Further, and correlative thereto, there is practical and necessary interest in an improved submersible that would have a more shallow draft as compared to present constructions. Brief Summary of the Invention The present invention embraces the use of interconnected cells or chambers, having spherical curvatures, to form the pressure hull, and wherein the working volume thereof, occupied by crew and equipment, is maintained at substantially one atmosphere irrespective of craft depth. While such shapes have been known in very general terms for submarine hulls and to a very limited extent hitherto, as in U.S. Patent 3,413,947 to Picard or in Italian Patent 715,120 and British Patent 279,483, the prior development is only incipient in concept and not suggestive of advanced structures of such character of the present invention. In the present invention, the utilization thereof in especially unique forms, as a hexagonal, looped, or arcuate array of spheres (or cells) for personnel and equipment, inter alia, results in the provision of massive structural strength of the submersible or submarine against the external hydrostatic pressures at great depths or during cycles of changing pressure during dive or ascent. Yet with exceedingly high pressure resistance and interior volume or space for all needed personnel, equipment, and machinery, the bulkhead height can be reduced to less than half that of conventional submarine bulkhead diameter, with resultant reduced wetted area and lower power requirements for the same speed. In a principal form of the invention, a looped array of six such cells or modules defines a central opening or void which receives a seventh cell of similar or greater diameter than the other cells, which seventh cell significantly reinforces and buttresses the hexagonal array, and wherein further, all cell intersections form flat vertical bulkheads. Such an arrangement, in broadest terms, may be said to resemble a so-configured cluster of soap bubbles. This preferred hexagonal form as naturally occurs in snowflakes, honeycombs, and divers crystalline formations in nature is regarded as having the greatest strength as well as the most efficient integrated application of structure. In the present invention, as applied to submersible craft, further extension of this cellular structure by the addition of other looped arrays will provide the needs of even larger displacement hulls, and without resorting to the difficulties or even impossibilities of hulls of ever increasing diameters, and in preference to increasing cell spherical diameters in the present invention. In like manner, a structured array of similar but smaller spherically curved cells, interconnected in clusters or groups of three, four, or five, and having similar common vertical bulkheads, are suited to smaller submarine applications, as for marine research or special testing. Relatively low vertical profile, shallow draft hull configurations following from utilization of the pressure hull of the invention provide yet the further advantages of a more sleek hydrodynamic external hull for surface and subsurface speed and maneuverability. Other objects and advantages will become apparent from the detailed description of the invention hereinafter. Brief Description of the Drawings The invention will be better understood in conjunction with the accompanying drawings, in which: Fig. 1 is a general perspective illustration of a shallow draft submersible of the invention wherein the spherical cell structures forming the pressure hull thereof lie within the exterior streamlined hydrodynamic hull; Fig. 2 is a diagrammatic illustration of a single generally spherical cell according to the invention, and showing the preferred location of weld lines between the cell sections; Fig. 3 is an isometric view of a seventh cell which occupies the central area of an hexagonal six-cell open center array, showing the upper and lower domes and with the bulkheads along the hexagonal faces being removed for clarity; Fig. 4 is a diagrammatic isometric view of a hexagonal array of cells including the illustration of the central top dome which creates the hexagonal prismatic core; Fig. 5 is a diagrammatic side view of the submersible generally corresponding to Fig. l, and including reinforcing members extending between the cells and the exterior hydrodynamic hull; Fig. 6 is an isometric view similar showing the basic hexagonal array of cells with center dome, and further illustrating rearwardly extending adjacent cells, as may be employed for propulsion machinery compartmentation or other purposes; Fig. 7 is a fragmentary view of two adjacent cells intersecting a surrounding reinforcing hoop and with a fragmentary portion of a inner bulkhead between the cells, and with an indication of connection between the hoop an the exoskeleton; Fig. 8a is a diagrammatic plan view of a modified cell arrangement including two central cell areas with eight surrounding cells, and illustrating an exoskeleton structure tying the several cells and the outer hydrodynamic hull together generally at the bulkheads at each cell juncture; Fig. 8b is similar to Fig. 8a, but in a side view; Fig. 9a is a diagrammatic illustration of a modified form of pressure hull having four connected cells as well as a central core or opening; Fig. 9b is a diagrammatic illustration of a further modified form of pressure hull having four connected cells with no central core or opening; Fig. 9c is a diagrammatic illustration of a yet further modified form of pressure hull having three connected cells with no central core or opening; and. Fig. 10 is a diagrammatic isometric view generally showing the bulkheading arrangement in the preferred hexagonal array of cells including the reinforcing hoops therearound, and further including a showing of the lower dome portion in the central area as well as generally complete cells at one hexagonal position and as satellite cells on either side thereof. Detailed Description of the Invention To facilitate quick reference to the drawings and the following description, the following glossary of reference characters is provided: HI - hemispherical head member of cell H2 - spherically curved center section member of cell 10 - overall shallow draft submarine or submersible 12 - hydrodynamic outer hull 14 - pressure hull of spherical cells within outer hull 16 - truncated spherical cell 18 - exoskeleton between inner and outer hulls P20 - welded seam between upper HI and H2 22 - truncated opening in cell P24 - welded seam between lower HI and H2 26 - rigidifying hoops between cells 28 - central core including bulkheads, and upper and lower part-hemispherical caps 30 - welds between cells 32 - four cell array with center core 34 - four cell array without center core 36 - three cell array without center core 38 - bulkheads between cells 40 - domes over central core area In Fig. 1 an illustrative shallow-draft submersible or submarine 10 according to the invention is shown wherein the exterior hydrodynamic hull 12 is appropriately and preferably streamlined. In the illustrative form, the same is somewhat of a flattened ellipsoid configuration similar in broad respects to a manta ray, but it is to be understood that any alternative external effective and generally flattened submarine hull configuration may be used within the spirit of the inventive concepts herein. The unique and inventive pressure hull of the invention is defined by the connected plural spherical cell working volume within the exterior hull 12 of submarine 10, which plural cell system includes those generally indicated at 14 in Fig. l. As such, the same presents an overall illustration of a submersible/submarine, wherein the several internal cell spheres define the pressure hull of maximum resistance to high and changing or cycling sea hydrostatic pressures, while the outer skin or hydrodynamic hull 12 is ^ not subjected to pressure extremes in usual manner by the presence of water pressures or air pressures between the external hull and the cells providing the crew, equipment, and machinery working space within the cells 16, which space is normally and necessarily and customarily maintained at about one atmosphere of pressure for normal functioning of crew and equipment. Further, so far as propulsion power, whether nuclear, diesel, or any defensive or offensive armaments are concerned, as well as control surfaces and the like, the submersibles of the invention may be provided as desired with the same in known manner, and which do not form a part of the present invention. As indicated disposed within the exterior hull 12 is the pressure hull 14 of the invention. The same is formed from a plurality of substantially spherical cells 16, a single one of which is illustrated in enlarged form in Fig. 2. The checked pattern thereon does not represent a structural feature, but, is provided for clarity of illustration as to internal and external relationships. The cells 16 are substantial in size thereby to accommodate crew, living quarters, and equipment, flooring, storage, etc. , all as is customary in submarine and submersible vessels. The diameter and number of spherical cells 16 may be greater or smaller as needed. For example, in Figs. 1 and 6, the auxiliary cells 16a or 16b are attached to the primary six-cell array, and may be of different size than the principal cells 16. As seen in Fig. 6, the cells 16a and 16b attached to hexagonal array of cells 16 are diametrically sized to accommodate the external hydrodynamic hull 12, as well as is necessary to accommodate crew, equipment or machinery therein. The aforementioned patent to Picard 3,413,947 is illustrative of differing cell sizes for varying purposes. The cells 16 can be manufactured and fabricated from selected steel, crafted alloys, or exotic metals as necessary to meet depth/pressure requirements and manufacturing considerations. Techniques for formation of spheres 16 employ current fabrication techniques which are applicable to both commercial and military markets, and as such can conform to all ANSI, MIL-SPEC and other applicable inspections as necessary to insure structural integrity. Preferably, again for ease of manufacture, the cells 16 are provided and assembled for each cell in two hemispherical sections HI, HI and a generally part-spherical section H2 as generally indicated in Fig. 2. The upper and lower hemi-heads HI, HI , are respectively joined to center section H2 along globe-like parallels P20 and P24. Such hemispheric connection is made by welding. As indicated, several of the cells 16 are serially connected as in the hexagonal matrix of Fig. 3, for example, and along with added cells 16a and 16b form the basic pressure hull 14 seen in Fig. 1. In order to provide communication between the cells 16 and appropriate access by personnel and to equipment, each cell 16 that is connected to an adjacent cell 16 is truncated or hemispherically incomplete to define an opening or openings 22 of desired size to permit passage of personnel, equipment and connections therethrough as necessary in the assembled hull 14, as noted further hereinafter. In order to maximize the strength of the structure through the spherical curve of each cell 16, the size of the opening 22 is as small as reasonably feasible, extending preferably not over about o 60 of arc. The spherical cells are sealingly connected to each other at the openings 22, which are preferably peripherally flanged thereat, by weldments and like means as seen in Fig. 7. To rigidify and strengthen the connection, a separate annulus or hoop 26 as diagrammatically seen in Fig. 5 and in partial section in Fig. 7 extends completely about each pair of the confronting openings 22 of adjacent cells 16, and is secured to each spherical member as by welding 30, Fig. 7. Within the hoops 26 at the cell junctures suitable bulkheads 38 are provided between the cells with appropriate hatches therethrough. Fig. 10 illustratively shows such bulkheads in diagrammatic form to demonstrate clearly the relationship of the bulkheads to the pressure hull. In this regard, the unique hexagonal array with the bulkhead locations as shown provides maximum safety and strength with minimum usage of material. Thus, as illustrative of a cell and bulkhead dimensioning in accordance with the invention as compared to conventional cylindrical form submarine practice wherein a usual bulkhead may be 30 feet in diameter: Example: Diameter of Cell 16 = 30 Feet; Diameter at Bulkhead 38 *= 15 Feet Submarine bulkhead area herein **= 7.5»D = 176.715 Sq. Ft. Conventional bulkhead area = 15.0»B = 706.858 Sq. Ft. Reduction in Steel Required for Each Bulkhead Construction: 176.715 - 796.858 = 25%, or a 75% Reduction in Steel As above indicated, volumetric requirements of conventional cylindrical submarines are immense, whereby submarines use 40-foot diameter bulkheads, with therefore an area in excess of 1,250 sq. ft. In the present invention with the horizontal array of cells 16 providing vast volume space with the other advantages as noted, it is expected from design considerations that the maximum bulkhead diameter will be only 16.5 feet with a maximum area of 213.8 square feet, with resultant like massive reduction in materiel, cost, and weight. At a selected point or points in the connected array of cells 16, access ports and air locks from the outside may be had as necessary for personnel or equipment connections, the same having appropriate sealable hatches, as is well known in submersible or submarine construction. Further, to the extent feasible, necessary penetrating connections can be made at the junctures of cells 16, thereby maintaining to the maximum extent possible the structural and leakproof integrity of the spherically curved system. The hoops 26, circular in form and rigidified by their mechanical association with the spheres 16, form attachment points for the exoskeleton 18 extending between the pressure hull 14 and the external hull 12, thereby along with companion trusses and reinforcing means therebetween providing an effective exoskeleton 18 supporting the hydrodynamic hull 12 about the pressure hull 14. In so doing significant reinforcement against bending stresses directed toward the pressure hull is provided. Further, the integrated nature of the spherical cells 16 permit as needed, or in the event of accident, a free flood area and volume between the hulls without jeopardizing the pressure hull integrity. A further function of the looped array of cells 16 is the multiple access to each cell from up to three adjacent cells, with resultant improved safety and work or maintenance access, in striking contrast to the limited linear arrangement of usual compartments in a conventional cylindrical submarine. By way of example, a flooding of a mid-compartment of a conventional submarine can eliminate access between forward and aft compartments on wither side thereof. In the subject invention, in the array of Fig. 8, for example, flooding of any one or in most cases even two cells does not block access to all others. As indicated, ir ~ne form of the invention, an array of six cells 16 is _ hexagonal form as in Figs. 4 and 5 thereby to define a central open area or core 28. The array is further immensely strengthened by the provision of part-spherical upper and lower domes 40. Domes 40 have their peripheral skirts scalloped or contoured so as to seat upon and be complementary with the contiguous surfaces of the six spherical cells 16, and are sealed thereto as by welding. By so doing, the arched part-spherical domes not only impart additional strength to the hexagon array, but also convert the core space into an integral part of the pressure hull volume for use. Accordingly, one or more of the spherical cells 16 may be provided with access ports on an inside arcuate face to as to permit utilization of the now-closed core space 28. The foregoing description has emphasized the utility and volume of a hexagonal array of six cells 18. It is evident that five such cells arranged in a pentagon, or other circular arrays may be provided to gain a central space which may be closed by domes similar to those at 28, as in the four-cell array of Fig. 9a, or may have other arrangements without a central core section between the array of cells 16, as in Figs. 9b or 9c, for example. In like manner, in lieu of the central upper and lower domes 40, a further cell 16 may occupy the central space of the hexagon, if desired, although not providing the additional internal volume achieved with the domes. It will be seen that in all forms of the invention, all exterior surfaces of the pressure hull are spherically convex for maximum strength and resistance to undersea external hydrostatic pressures. Further, by use of the common spherical form for all components, and including the part-spherical form of the domes, a maximum reduction in fabrication costs is obtained. While disclosed in the context of submersible or submarine construction, to which the system is most apt as a radical improvement over existing submersible structures, it is evident that the concepts herein may be utilized in many other environments than that of personnel and subsea vehicles, as for example, diverse forms of fluid handling equipment, whether liquid or gaseous, which may or may not require protected personnel and machinery, as in offshore subsea wellhead operations, inter alia.

Claims: What I claim is : 1. A pressure hull for submersibles or submarines and the like comprising a plurality of generally spherical cells, each said cell being truncated at at least one point to define an opening of limited arcuate extent communicating interiorly of said cell, said cells being arranged in a loop array with the opening in each cell confronting a like opening in the next adjacent cell, and with the loop array defining an open area centrally thereof, an additional cell disposed in the central area and having a like connecting opening therein, wherein further at least one of the loop array cells has a complementary opening communicating with the additional cell, structure fixedly securing the cells to each other in leakproof relation at said confronting openings, thereby to define a connected internal space between at least two cells for utilization, the structure including a circular reinforcing hoop disposed between the cells and in surrounding relation about the cell openings and secured to each adjacent cell thereat, and, at least one access port on an outer face of at least one spherical cell of the loop array for entry to and exit from the cells internal space. 2. The pressure hull of Claim 1 wherein the communicating cell openings each extend over an arc of no o greater than about 75 . 3. The pressure hull of Claim 1 wherein each cell has a pair of said openings, thereby to provide a continuous internal space interconnecting all cells in the loop array. 4. The pressure hull of Claim 1 wherein each cell is fabricated from three components, namely upper and lower domed portions, and an intermediate truncated generally spherical portion connected at its upper and lower edges respectively with the upper and lower domed cell portions. 5. The pressure hull of Claim 1 wherein there are six cells arrayed in a hexagonal loop array pattern and having the central open area. 6. A pressure hull for submersibles or submarines comprising a plurality of generally spherical cells, each cell being truncated at at least one point to define an opening of limited arcuate extent communicating interiorly of the cell, the cells being arranged in a closed loop array with an opening in each cell confronting a like opening in the next adjacent cell, and with the array defining an open area centrally thereof, structure fixedly securing the cells to each other in leakproof relation at the confronting openings, thereby to define a connected internal space between at least two cells for utilization, a pair of generally spherically curved domes overlying and underlying the central area, [and] structure securing the domes to the cells in leakproof relation thereto, thereby to define a sealed usable central space within the loop array, and, at least one access port on the outer face of at least one cell for entry to and exit from the cells internal space. 7. The pressure hull of Claim 6 further including at least one access port on the inner face of one of the cells communicating with the central space. 8. The pressure hull of Claim 1 wherein the additional spherical cell is secured to all the surrounding spherical cells. 9. The pressure hull of Claim 1 further including bulkheads within the hoops. 10. A submersible or submarine comprising an external hydrodynamic hull and a plurality of substantially spherical cells disposed within the hydrodynamic hull to define a pressure hull therewithin, the cells being arranged in a common plane and in a loop defining a central open area, each of the cells being truncated at two spaced points to define two openings of limited arcuate extent, with an opening in each cell confronting a like opening in the next adjacent cell, a pair of generally spherically curved domes overlying and underlying said central area, means securing the domes to the cells in leakproof relation thereto, thereby to define a sealed usable central space within the loop array, structure fixedly securing the cells to each other at the confronting openings in leakproof relation, thereby to define a loop-like connected internal space for utilization, the structure including a circular hoop about the openings and secured to each adjacent cell thereat, and, at least one access port on the outer face of at least one cell. 11. The submersible or submarine of Claim 10 wherein bracing connections extend outwardly of the hoops and between the hoops and the external hull, thereby to support the hydrodynamic hull and fixedly locate the pressure hull therewithin rigidly supported against bending stresses. 12. The submersible or submarine of Claim 11 wherein the bracing connections include watertight bulkheads between the hoops and external hull. 13. The submersible or submarine of Claim 12 wherein the bulkheads between the hoops and external hull extend at substantially right angles to the hoops between the cells, and thereby define a honeycomb-like configuration of chambers between the multiple cell pressure hull and the external hydrodynamic hull for increased rigidity with relative light weight. 14. The submersible or submarine of Claim 12 wherein the loop array of the cells is generally planar and the external hydrodynamic hull is generally flattened, thereby to provide a minimum wetted external surface with higher underwater efficiency. 15. The submersible or submarine of Claim 10 wherein the cell openings each extend over an arc of no greater than about 75 . 16. The submersible or submarine of Claim 10 wherein there are at least five of the cells arranged in a substantially planar array to define an open area centrally thereof within the external hull. 17. The submersible or submarine of Claim 16 wherein there are six of the cells arrayed in a hexagonal pattern having the central open area. 18. The submersible or submarine of Claim 11 wherein a pair of generally spherically curved domes overlie and underlie the central open area, and means securing said domes to the cells in leakproof relation thereto, thereby to define a sealed usable central space therebetween and within the external hull. 19. The submersible or submarine of Claim 11 further including at least one access port on the inner face of one of said cells communicating with the central open area. 20. A submersible or submarine comprising an external hydrodynamic hull and a plurality of substantially spherical cells disposed within the hydrodynamic hull to define a pressure hull therewithin, each of the cells being truncated at two spaced points to define two openings of limited arcuate extent, the cells being arranged in a loop array with a said opening in each cell confronting a like opening in the next adjacent cell, and with the loop array defining an open area centrally thereof, an additional cell disposed in the central open area and having an opening therein, wherein further at least one of the loop array spherical cells has a complementary opening communicating with the additional cell, and structure sealing and securing the last-named cells to each other. 21. The submersible or submarine of Claim 20 wherein the additional cell is secured to all surrounding cells. 22. A submersible or submarine comprising an external hydrodynamic hull of generally streamlined generally planar configuration and a plurality of generally spherical cells disposed within said hydrodynamic hull in a common plane to define a pressure hull therewithin, each of the cells being truncated at two spaced points to define two openings of limited arcuate extent, the cells being arranged in a loop array with an opening in each cell confronting a like opening in the next adjacent cell, and with the loop array defining an open area centrally thereof, a pair of generally spherically curved domes overlying and underlying the central area, structure securing said domes to the cells in leakproof relation thereto, thereby to define a sealed usable central space within the loop array, structure fixedly securing the cells to each other at the confronting openings in leakproof relation, thereby to define a loop-like connected internal space through the cells for utilization, at least one additional generally spherical cell extending generally outwardly from one cell of the loop array and in said common plane, at least one access port between one of the cells and the central space within the domes, and, propulsion equipment within the additional cell. 23. The submersible or submarine of Claim 22 wherein the fixedly securing structure at the cell openings further include bracing elements extending radially therefrom and fixed to the interior of said hydrodynamic hull. 24. A submersible craft comprising, a pressure hull including a plurality of cells each having a generally spherical exterior surface with the cells arranged in a common plane, the cells each having truncated generally circular openings, with each two adjacent cells connected to each other at the openings, flat bulkheads between the cells at the openings, and, hoop structures surrounding the bulkheads at the openings and connected to the bulkheads by welding, thereby to define a cell array of generally honeycomb-like appearance for maximum mutual reinforcement and distribution of stresses from external subsea pressures. 25. The submersible craft of Claim 24 further including an external generally flattened hydrodynamic hull enclosing the pressure hull, bracing structure extending between the bulkheads and the interior of the hydrodynamic hull further defining additional honeycomb-like chambers between the hydrodynamic and pressure hulls.

Inventors: NESS C CLIFFORD, NESS, C., CLIFFORD
Applicants: NESS C CLIFFORD, NESS, C., CLIFFORD
Application year: 1995
Main classification: B63G8
IPC codes: B63B3