Abstract:
A ship has at least one deck which is inventively latticed in a regular (e.g., repeating) geometric pattern of hatches. The hatches of each such inventive deck are shaped in standardized geometric forms and disposed in diagonally contiguous interrelationships, thereby enhancing the structural characteristics of the deck and of the ship, especially in terms of attenuation of warping deflections and resultant stresses.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to structures for human accommodation, more particularly to construction or architecture of such structures, terrestrial or aquatic, having one or more relatively large interior openings. 
     Certain types of marine vessels, such as container ships, have large interior openings (in marine terminology, &#34;hatches&#34;) which permit and facilitate access, e.g., to cargo, interior spaces and modular payloads. Conventionally, cargo hatches are large rectangular openings in the deck which allow for easy loading and discharge of cargo; typically, such rectangular openings replace a substantial portion of the deck area, thereby leaving a significantly reduced deck structure. 
     This reduction of the deck structure in conventionally constructed ships can present structural difficulties. In effect to some degree, a conventionally constructed cargo ship with large hatch openings has an &#34;open&#34; top and is thus analogous to a shoe box; subjection to strains of the conventionally constructed ship which has large openings can cause the ship to behave in a similar manner as would a shoe box under similar circumstances. 
     In particular, if the conventionally constructed ship having large hatches is subjected to a twisting load, the structurally reduced deck has reduced rigidity and hence reduced ability to control the deflections from this twist. Such deflections can have adverse effects; for example, large stresses at the hatch corners can lead to structural failure. 
     Conventional approaches to addressing these concerns have involved the utilization of structural reinforcement. One methodology has included increasing the thickness of the plating in the deck structure. Another methodology has included the addition of longitudinal box girders to increase the torsional and longitudinal rigidity of the ship hull. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an object of the present invention to provide, for a marine vessel, a hatch system which renders an improved structural response of the marine vessel to torsional and other loads. 
     It is another object of this invention to provide such a hatch system which does not entail utilization of auxiliary structure. 
     The present invention features an approximately planar structure which is provided with a plurality of voids. An inventive void is described herein as &#34;geometric&#34; so as to impart the notion that the void approximately defines a closed plane figure wherein the perimeter has particular geometric characteristics in terms of length, straightness, curvature and angularity. For most inventive embodiments the voids are preferably distributed in a regular pattern, i.e., conforming to some principle of order, symmetry, periodicity, repetition, recurrence, uniformity and/or homogeneity; the voids are thus arranged in a cross-diagonal motif which enhances the ability to withstand stresses, strains and deflections when the structure is utilized partitionally, e.g., as a floor, platform or deck, in the context of a plural-level structure such as a building, ship or other comparatively large edifice. 
     The inventive apertural network is especially advantageous when used in connection with marine vessels which, when at sea, are subjected to various forms of potentially damaging or deforming loads. The present invention can be practiced in association with various marine vessel hull forms or types, in particular either with conventional single hull framing or with double hull framing. Container ships are a notable genre of marine vessels which can particularly avail this invention. 
     In marine applications, especially, this invention efficiently and efficaciously utilizes structural material which is included in the construction of one or more decks or one or more portions thereof. The diagonally crisscross hatch pattern of the present invention adds torsional rigidity to the ship structure, thereby controlling, mitigating or reducing the warping deflections and resulting stresses. Conventional measures for controlling high stresses due to hull warping, such as increasing plating thickness or otherwise implementing complex detail or reinforcement, can thus be obviated or avoided by this invention. 
     In testing conducted by the U.S. Navy, a finite element model was analyzed whereby the model was subjected to twisting loading. The resultant stresses of the model were shown to be about three to four times less than would ensue if a typical rectangular-hatch ship were subjected to such loading. 
     Moreover, this invention&#39;s configurational standarization of the openings accommodates the modularity which is typical of cargo containment; items of same or similar form or dimension (modules, containerized cargo, payloads, etc.) can be inserted into the openings. In fact, inventive practice can dictate shapes and sizes of the openings in conformity with, or otherwise in anticipation of, the shapes and sizes of the entitities to be passed therethrough. 
     Commercial container ships are among the various genres of marine vessels which can avail the present invention. Container ships are used for transporting cargos which typically are containerized or modularized in rectangular form; hence, container ships conventionally have large rectangular hatches to accommodate such rectangular cargos. The present invention can afford structural benefits to container ships while still accommodating their rectangularly shaped cargos. 
     For some marine applications, the inventive diagonal hatch system includes diagonal hatch patterns on each of a plurality of decks, at least two of which can be vertically adjacent decks; such repetition of the inventive hatch pattern on one or more internal decks, in addition to the top deck, can accommodate entities (e.g., cargo modules) of virtually any desired depth inside the hull. 
     In accordance with many embodiments of this invention, a plural-level structure comprises at least one partition which approximately defines a horizontal plane for separating two vertically consecutive levels of the plural-level structure. The partition is provided with at least four apertures for permitting communication between the two separated levels. The apertures are arranged, in the partition, in a plural number of tiers rows which are approximately parallel with respect to each other. This plural-tier arrangement is characterized by an approximately parallelly iterative positively diagonal apertural alignment mode and an approximately parallelly iterative negatively diagonal apertural alignment mode, whereby successive apertures in each positively diagonal apertural alignment have abutting sides which are approximately parallel to each other and which are approximately perpendicular to the positively diagonal apertural alignment, and whereby successive apertures in each negatively diagonal apertural alignment have abutting sides which are approximately parallel to each other and which are approximately perpendicular to the negatively diagonal apertural alignment. 
     According to some inventive embodiments, a plural-level structure comprises at least two vertically consecutive partitions for separating at least three vertically consecutive levels of the plural-level structure. Each partition is approximately identically provided with at least four geometric (e.g., polygonal) apertures for permitting communication between at least three separated levels. At least two consecutive partitions are configured with respect to one another whereby the corresponding plural-tier arrangements are approximately in vertical spatial alignment. 
     According to some embodiments of the present invention, a plural-level structure comprises at least one wall (in marine terminology, &#34;bulkhead&#34;) which engages at least one partition. The wall traverses or substantially traverses the partition while circumventing one or more neighboring apertures. According to some such embodiments, the wall borders upon at least a portion of each of at least two apertures. 
     For embodiments wherein a plurality of inventively apertured partitions are provided in approximate vertical apertural alignment, at least one wall can be provided which engages at least two such partitions, wherein the wall at least substantially traverses each partition while circumventing one or more neighboring apertures in each partition; according to some such embodiments, the wall borders upon at least a portion of each of at least two apertures corresponding to each partition. In fact, some such inventive embodiments provide at least one such wall which at least partially extends (in an approximately vertical direction) into each of at least two levels, thereby intersecting at least one partition. 
     When the plural-level structure is a marine vessel (such as a cargo ship or a military ship), it may be particularly beneficial in inventive practice to orient the tiers approximately longitudinally with respect to the marine vessel, i.e., so that the tiers are not only approximately parallel to each other but are also approximately parallel to the imaginary longitudinal axis of the marine vessel. With the tiers of the hatches being thus oriented, the diagonally crosswise distribution of the hatches can more optimally serve to amplify or embellish resistance of the marine vessel to deflections and stresses of one or more decks due to warping or twisting of the hull. 
     According to most embodiments of the present invention, at least one pair of adjacent positively diagonal alignments define therebetween a positively diagonal traversal of the plural-tier arrangement, and at least one pair of adjacent negatively diagonal alignments define therebetween a negatively diagonal traversal of the plural-tier arrangement. This inventive featural aspect of cross-diagonal structural continuums can contribute to the overall structural fortification afforded by the present invention; this beneficial effect may be heightened by a regularity of the inventive apertural pattern, in that the cross-diagonal structural continuums would likewise be characterized by a type of regularity of distribution. When used in association with a marine vessel, for example, the cross-diagonal structural continuums of an inventively hatched deck can extend at least substantially across the marine vessel (from port to starboard) and, like a truss or rigid framework, thereby afford a structurally supportive quality. At the same time, the inventive cross-diagonal apertural lattice can afford a structurally resiliant quality in response to stresses, strains and deflections. 
     Many inventive embodiments provide a positively diagonal apertural alignment mode and a negatively diagonal apertural alignment mode which are at an approximately equal orientation with respect to the direction of the tiers (and hence at an approximately equal orientation with respect to the direction of the marine vessel&#39;s longitudinal axis); for most such embodiments, this orientation is in the approximate range between 30° and 60°. Some such inventive embodiments provide a positively diagonal apertural alignment mode and a negatively diagonal apertural alignment mode which are each oriented at approximately 45° with respect to the direction of the tiers (and hence at approximately 45° with respect to the direction of the marine vessel&#39;s longitudinal axis) and are thus oriented approximately orthogonally with respect to each other. 
     A noteworthy class of inventive embodiments includes a two-tier arrangement of approximately congruent symmetrical hexagonal hatches. Each hexagonal hatch has a double-right-angle-interposed side, a positively beveled side and a negatively beveled side. Every beveled side has approximately the same length. Each tier has its own hexagonal apertures approximately equivalently situated so that their double-right-angle-interposed sides face opposite the other tier. The abutting sides for each positively diagonal alignment comprise two negatively beveled sides. The abutting sides for each negatively diagonal alignment comprise two positively beveled sides. 
     Another noteworthy class of inventive embodiments includes a three-tier arrangement of hatches. Two outer tiers are of approximately congruent symmetrical hexagonal apertures. An intermediate tier is of approximately congruent symmetrical octagonal apertures. Each hexagonal aperture has a double-right-angle-interposed side, a positively beveled side and a negatively beveled side. Each outer tier has its own hexagonal apertures approximately equivalently situated so that their double-right-angle-interposed sides face opposite the intermediate tier. Each octogonal aperture has two positively beveled sides and two negatively beveled sides. Every beveled side has approximately the same length. The abutting sides for each positively diagonal alignment comprise at least one pair of negatively beveled sides. The abutting sides for at least one positively diagonal alignment comprise two pairs of the negatively beveled sides. The abutting sides for each negatively diagonal alignment comprise at least one pair of positively beveled sides. The abutting sides for at least one negatively diagonal alignment comprise two pairs of positively beveled sides. 
     Other objects, advantages and features of this invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the present invention may be clearly understood, it will now be described, by way of example, with reference to the accompanying drawings, wherein like numbers indicate the same or similar components, and wherein: 
     FIG. 1 is a partial plan view of an inventive deck embodiment, wherein the deck is provided with hexagonally and octagonally shaped voids. 
     FIG. 1A is the view of the inventive deck embodiment as shown in FIG. 1, additionally showing some imaginary delineations. 
     FIG. 1B is the view of the inventive deck embodiment as shown in FIG. 1, additionally showing an inventive embodiment of a distribution of bulkheads. 
     FIG. 2 is a partial plan view of another inventive deck embodiment, wherein the deck is provided with hexagonally shaped voids. 
     FIG. 2A is the view of the inventive deck embodiment as shown in FIG. 2, additionally showing some imaginary delineations. 
     FIG. 3 is a partial sectional perspective view of an inventive ship embodiment, shown port side looking forward, wherein the ship comprises an inventive deck embodiment and an inventive bulkhead embodiment such as shown in FIG. 1B. 
     FIG. 4 is a view, similar to the view shown in FIG. 3, of the inventive ship embodiment shown in FIG. 3, here shown port side looking aft. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, deck 10a is an approximately planar structure having a plurality of hexagonal hatches 12a hex  and octagonal hatches 12 oct . Rectangular array 14a has three horizontal rows and several vertical columns of hexagonal hatches 12a hex  and octagonal hatches 12 oct . 
     First row 16a 1  and third row 16a 3  are the outer rows, and second row 16a 2  is the intermediate row. First row 16a, and third row 16a 3  each have a plurality of hexagonal hatches 12a hex . Second row 16a 2  has a plurality of octagonal hatches 12 oct . The columns alternate between having two hexagonal hatches 12a hex  and having one octagonal hatch 12 oct . As shown in FIG. 1, columns 18a 1 , 18a 3 , 18a 7  each have one octagonal hatch 12 oct  ; columns 18a 2 , 18a 4  and 18a 6  each have two hexagonal hatches 12a hex . 
     Every opening in first row 16a 1  and third row 16a 3  is an approximately congruent hexagonal hatch 12a hex . Every hexagonal hatch 12a hex  is a rectanguloid which has a pair of approximately parallel approximately equal columnwise hexagonal sides 20a and 22a, a pair of approximately parallel unequal rowwise hexagonal sides 24a and 26a, and a pair of approximately equal hexagonal oblique sides 28a and 30a adjoining the ends of the shorter rowwise hexagonal side 26a. 
     Every opening in second row 16a 2  is an approximately congruent octagonal hatch 12 oct . Every octagonal hatch 12 oct  has a pair of approximately parallel approximately equal columnwise octagonal sides 32 and 34, a pair of approximately parallel approximately equal rowwise octagonal sides 36 and 38, a first pair of approximately parallel approximately equal oblique octagonal sides 40 and 42, and a second pair of approximately parallel approximately equal oblique octagonal sides 44 and 46. Each oblique octagonal side 40, 42, 44, and 46 adjoins an end of a columnwise octagonal side 32 or 34 and an end of a rowwise octagonal side 36 or 38. 
     For every hexagonal hatch 12a hex , the longer rowwise hexagonal side 24a faces outwardly with respect to array 14a. Every hexagonal hatch 12a hex  in first row 16a 1  is oriented approximately equally with respect to each other. Every octagonal hatch 12 oct  in second row 16a 2  is oriented approximately equally with respect to each other. Every hexagonal hatch 12a hex  in third row 16a 3  is oriented approximately equally with respect to each other and approximately invertedly with respect to the hexagonal hatches 12a hex  in first row 16a 1 . 
     With reference to FIG. 2, deck 10b is an approximately planar structure having a plurality of approximately congruent hexagonal hatches 12b hex . Rectangular array 14b has two horizontal rows and several vertical columns of hexagonal hatches 12a hex . First row 16b 1  and second row 16b 2  each have a plurality of hexagonal hatches 12b hex . Every column has a hexagonal hatch 12b hex  ; as shown in FIG. 2, columns 18b 1 , 18b 2 , 18b 3 , 18b 4  and 18b 5  each have one hexagonal hatch 12b hex . 
     Every hexagonal hatch 12b hex  is a rectanguloid which has a pair of approximately parallel approximately equal columnwise hexagonal sides 20b and 22b, a pair of approximately parallel unequal rowwise hexagonal sides 24b and 26b, and a pair of approximately equal hexagonal oblique sides 28b and 30b adjoining the ends of the shorter rowwise hexagonal side 26b. For every hexagonal hatch 12b hex , the longer rowwise hexagonal side 24b faces outwardly with respect to array 14b. Every hexagonal hatch 12b hex  in first row 16b 1  is oriented approximately equally with respect to each other. Every hexagonal hatch 12b hex  in second row 16b 2  is oriented approximately equally with respect to each other and approximately invertedly with respect to the hexagonal hatches 12b hex  in first row 16b 1 . 
     Still referring to FIG. 2 and again referring to FIG. 1, it is seen that array 14a and array 14b bear certain similarities. For instance, hexagonal hatches 12a hex  shown in FIG. 1 and hexagonal hatches 12b hex  shown in FIG. 2 and are not &#34;similar&#34; in the strict geometric sense, but nevertheless are alike as having what is styled herein a &#34;rectanguloid&#34; shape, akin to an approximate rectangle which has had two adjacent corners beveled or chamfered. 
     Hexagonal hatch 12a hex  and hexagonal hatch 12b hex  are each a symmetrical hexagonal aperture having a double-right-angle-interposed side, a positively beveled side and a negatively beveled side. For each symmetrical hexagonal aperture: Two sides are situated in the columnwise direction, approximately parallel and having approximately the same length; two sides are situated in the rowwise direction, approximately parallel and having different lengths; and, two sides are each situated in an oblique direction, having approximately the same length and being disposed at approximately equal and opposite angles with respect to the rectangular array&#39;s rowwise (horizontal) direction. 
     Referring to FIG. 1A and FIG. 2A, each row of horizontal apertures has its hexagonal apertures approximately equivalently situated so that their double-right-angle-interposed sides face outward (away from the interior of the array), thereby approximately defining linear horizontal upper and lower borders (illustrated by dashed lines) of the respective arrays. The longer rowwise hexagonal sides 24a of first row 16a 1 , define imaginary upper border 48a of array 14a. The longer rowwise hexagonal sides 24a of third row 16a 3  define imaginary lower border 50a of array 14a. The longer rowwise hexagonal sides 24b of first row 16b 1  define imaginary upper border 48b of array 14b. The longer rowwise hexagonal sides 24b of second row 16b 2  define imaginary lower border 50b of array 14b. 
     Typically, at least part of a ship deck&#39;s perimeter is approximately coextensive with the ship hull; i.e., to some extent at least, the deck is approximately bounded along its periphery by the hull. Hence, for purposes of envisioning the deck in the context of a ship, the port side (left-hand side of ship as ship faces forward) edge 52a and starboard side (right-hand side of ship as is ship faces forward) edge 54a of deck 10a shown in FIG. 1, and the port side edge 52b and starboard side edge 54b of deck 10b shown in FIG. 2, may be considered as being approximately coincident with the lateral periphery (i.e., port side and starboard side, respectively) of the ship. 
     Imaginary upper border 48a of array 14a is near and approximately parallel to port edge 52a of deck 10a . Imaginary lower border 50a of array 14a is near and approximately parallel to starboard edge 54a of deck 10a. Imaginary upper border 48b of array 14b is near and approximately parallel to port edge 52b of deck 10b. Imaginary lower border 50b of array 14b is near and approximately parallel to starboard edge 54b of deck 10b. 
     Thus considering decks 10a and 10b, it is seen that the ship has an imaginary longitudinal (running fore and aft) axis of symmetry, shown in FIG. 1A and FIG. 2A as dashed line l, which is approximately midway between: port edge 52a and starboard edge 54a of deck 10a shown in FIG. 1A; imaginary upper border 48a and imaginary lower border 50a shown in FIG. 1A; port edge 52b and starboard edge 54b of deck 10b shown in FIG. 2A; imaginary upper border 48b and imaginary lower border 50b shown in FIG. 2A. 
     Longitudinal axis l rowwise bisects array 12a in FIG. 1A, and rowwise bisects array 12b in FIG. 2A. In FIG. 1A, row 16a 1  of octagonal hatches 12 oct  is likewise rowwise bisected by longitudinal axis l. In FIG. 2A, longitudinal axis l passes rowwise through the hexagonal hatches 12b hex  of both first row 16b 1  and second row 16b 2 . 
     At many locations, an oblique side of an opening faces an oblique side of a diagonally adjacent opening, thereby forming an interfacial portion (&#34;interface&#34;) of the approximately planar structure. With regard to the hatches shown in FIG. 1A, each hexagonal hatch 1a hex  has at least one oblique side 28a or 30a which is approximately parallel to and forms an &#34;interface&#34; (either a positive interface 60a p  or a negative interface 60a n ) with an octagonal oblique side 40, 42, 44 or 46 of an adjacent octagonal hatch 12 oct  which is in a next row 16a and a next column 18a. Every interface is oblique in either a selected positive direction (positive interface 60a p ) or a selected negative direction (negative interface 60a n ). 
     With regard to the hatches shown in FIG. 2A, each hexagonal hatch 12b hex  has at least one hexagonal oblique side 28b or 30b which is approximately parallel to and forms an &#34;interface&#34; (either a positive interface 60b p  or a negative interface 60b n ) with a hexagonal oblique side 28b or 30b of an adjacent hexagonal hatch 12b hex  which is in a next row 16b and a next column 18b; such an interface is shown to be formed by a hexagonal oblique side 28b with a hexagonal oblique side 28b, or by a hexagonal oblique side 30b with a hexagonal oblique side 30b. Every interface is oblique in either a selected positive direction (positive interface 60b p  or a selected negative direction (negative interface 60b n ). 
     The terms &#34;positive direction&#34; and &#34;negative direction&#34; are intended herein to refer to angles of orientation with respect to longitudinal axis l, wherein longitudinal axis l is designated the &#34;x axis&#34; analogue in an &#34;x-y&#34; Cartesian plane; hence, of the hatches shown in FIG. 1A and in FIG. 1B, in each figure approximately half of the oblique sides are positively directed (i.e., positively &#34;sloped&#34; in terms of deviation from longitudinal axis l) and approximately half of the oblique sides are negatively directed (i.e., negatively &#34;sloped&#34; in terms of deviation from longitudinal axis l). 
     Certain properties become manifest due to inherent symmetrical and geometrical aspects of each of array 14a and array 14b. Every interface is formed by a pair of abutting, approximately parallel oblique sides. The two abutting oblique sides and the interface formed thereby each define approximately the same positive or negative slope. In FIG. 1A, interfaces 60a p  (positively sloped) and 60a n  (negatively sloped) are aligned with each other, end-to-end approximately colinearly, in approximately the same positive and negative diagonal directions, as indicated by imaginary dashed diagonal lines da p  and da n , respectively. Similarly, in FIG. 2A, interfaces 60b p  (positively sloped) and 60b n  (negatively sloped) are aligned with each other, end-to-end approximately colinearly, in approximately the same positive and negative diagonal directions, as indicated by imaginary dashed diagonal lines db p  and db n , respectively. 
     In other words, in FIG. 1A, two positively sloped interfaces 60a p , when considered as connected end-to-end, medially define a positively sloped diagonal line da p  ; two negatively sloped interfaces 60a n , when considered as connected end-to-end, medially define a negatively sloped diagonal line da n . In FIG. 2A, each positively sloped interface 60b p  medially defines a positively sloped diagonal line db p  ; each negatively sloped interfaces 60b n  medially defines a negatively sloped diagonal line db n . 
     Moreover, two positively sloped interfaces 60a p , when considered as connected end-to-end, laterally peripherally define a positively sloped continuous rectilinear portion 62a p  (for example as indicated in FIG. 1A by a dashed border); two negatively sloped interfaces 60a n , when considered as connected end-to-end, laterally peripherally define a negatively sloped continuous rectilinear portion 62a n  (for example as indicated in FIG. 1A by a dashed border). One positively sloped interface 60b p  laterally peripherally defines a positively sloped continuous rectilinear portion 62b p  (for example as indicated in FIG. 2A by a dashed border); one negatively sloped interface 60b n  laterally peripherally defines a negatively sloped continuous rectilinear portion 62b n  (for example as indicated in FIG. 2A by a dashed border). 
     The interfaces 60a p  and 60a n  thereby approximately define in FIG. 1A a &#34;crisscross&#34; of diagonal, linear, continuous portions 62a p  and 62a n  of structure 10a; continuous portions 62a p  and 62a n  traverse array 14a. Similarly, the interfaces 60b p  and 60b n  thereby approximately define in FIG. 2A a &#34;crisscross&#34; of diagonal, linear, continuous portions 62b p  and 62b n  of structure 10b; continuous portions 62b p  and 62b n  traverse array 14b. 
     In FIG. 1A, each continuous portion 62a p  includes two interfaces 60a p  ; each continuous portion 62a n  includes two interfaces 60a n  In FIG. 2A, each continuous portion 62b p  includes one interface 60b p  ; each continuous portion 62b n  includes one interface 60b n . 
     In FIG. 1A, since upper border 48a and lower border 50a of array 14a are proximately parallel to starboard edge 52a and port edge 54a, respectively, of deck 10a, continuous portions 62a p  and 62a n  can be considered to traverse or substantially traverse deck 10a. Similarly, in FIG. 2A, since upper border 48b and lower border 50b of array 14b are proximately parallel to starboard edge 52b and port edge 54b, respectively, of deck 10b, continuous portions 62b p  and 62b n  can be considered to traverse or substantially traverse deck 10b. 
     Hence, in FIG. 1A, every continuous portion 62a p  , every diagonal line da p , every interface 60a p , every oblique hexagonal side 28a, every oblique octagonal side 40 and every oblique octagonal side 42 defines approximately the same positive slope; every continuous portion 62a n , every diagonal line da n , every interface 60a n , every oblique hexagonal side 30a, every oblique octagonal side 44 and every oblique octagonal side 46 defines approximately the same negative slope. Thus, all positively sloped diagonal lines da p  are approximately parallel to each other; all negatively sloped diagonal lines daa n  are approximately parallel to each other. 
     Similarly, in FIG. 2A, every continuous portion 62b p , every diagonal line ddb p , every interface 60b p , and every oblique hexagonal side 28b defines approximately the same positive slope; every continuous portion 62b n , every diagonal line ddb n , every interface 60b n  and every oblique hexagonal side 30b defines approximately the same negative slope. Thus, all positively sloped diagonal lines ddb p  are approximately parallel to each other; all negatively sloped diagonal lines dd b   n  are approximately parallel to each other. 
     Furthermore, in FIG. 1A, the absolute value of the positive slope defined by continuous portions 62a p , diagonal lines da p , interfaces 60a p , oblique hexagonal sides 28a, octagonal oblique sides 40 and oblique octagonal sides 42 is approximately equal to the absolute value of the negative slope defined by continuous portions 62a n , diagonal lines da n , interfaces 60a n , oblique hexagonal sides 30a, octagonal oblique sides 44 and oblique octagonal sides 46. Similarly, in FIG. 2A, the absolute value of the positive slope defined by continuous portions 62b, diagonal lines db p , interfaces 60b and oblique hexagonal sides 28b is approximately equal to the absolute value of the negative slope defined by continuous portions 62b n , diagonal lines ddb n , interfaces 60b n  and oblique hexagonal sides 30b. 
     In FIG. 1A and FIG. 1B, the slope (degree of deviation from longitudinal axis l) of each of diagonal lines da p , da n , db p  and db n  is represented to be roughly 45°; hence, diagonal lines da p  are approximately perpendicular with respect to diagonal lines da n , and diagonal lines db p  are approximately perpendicular with respect to diagonal lines db n . 
     It should be apparent to the ordinarily skilled artisan reading this disclosure that, in accordance with inventive principles, so long as the slope of each of diagonal lines da p  in array 14a is approximately equal, the slope of each of diagonal lines da n  in array 14a is approximately equal, the slope of each of diagonal lines db p  in array 14b is approximately equal, and the slope of each of diagonal lines db n  in array 14b is approximately equal: The basic geometric integrity of array 14a can be retained while varying one or both of the slopes of diagonal lines da p  and da n  ; the basic geometric integrity of array 14b can be retained while varying one or both of the slopes of diagonal lines db p  and db n  ; in array 14a, the absolute value of the slope of diagonal lines da p  need not equal the absolute value of the slope of diagonal lines da n  ; in array 14b, the absolute value of the slope of diagonal lines db p  need not equal the absolute value of the slope of diagonal lines db n . 
     Notable are certain shared attributes of array 14a and array 14b which are more generally characteristic of the present invention. Reference is still being made to FIG. 1A and FIG. 2A, wherein may be used more generic designations such as follows: approximately planar structure 10 (for deck 10a or deck 10b); geometric opening 12 (for hexagonal hatch 12a hex , octagonal hatch 12 oct  or hexagonal hatch 12b hex ); rectangular array 14 (for rectangular array 14a or rectangular array 14b); horizontal row 16 (for horizontal row 16a or horizontal row 16b); vertical column 18 (for vertical column 18a or vertical column 18b); interface 60 (for interface 60a or interface 60b); continuous portion 62 (for continuous portion 62a or continuous portion 62b). 
     In accordance with most embodiments of this invention, approximately planar structure 10 has a plurality of geometric openings 12 in a rectangular array 14 of at least two horizontal rows 16 and at least two vertical columns 18. Each geometric opening 12 has at least one oblique side which is approximately parallel to and forms an interface 60 with an oblique side of an adjacent geometric opening 12 which is in a next row 16 and a next column 18. Every interface 60 is oblique in either of a selected positive direction and a selected negative direction. The interfaces 60 are approximately aligned so as to approximately define a diagonal crisscross of continuous portions 62 of structure 10 which traverse array 14. Each continuous portion 62 includes at least one interface 60. 
     Other properties are seen to be generally true of inventive arrays 14 such as array 14a and array 14b. The rows 16 define rectilinear horizontal sections which are not discrete with respect to each other. Similarly, the columns 18 define rectilinear vertical sections which are not discrete with respect to each other. Rather, there is partial &#34;overlap&#34; between adjacent rows 16 and between adjacent columns 18. This inventive feature entails sufficient propinquity of each pair of adjacent oblique sides which form an interface 60, thereby assuring both (i) a relatively large total open area in structure 10 and (ii) a distinct cross-diagonal pattern of continuous portions 62 in structure 10. 
     Moreover, each intersection of a row 16 with a column 18 defines a common structural area of structure 10. Each intersection of first row 16a 1  or third row 16a 3  with a column 18a defines an approximately rectangular flanking platform 64a f  which approximately coincides with a segment of upper border 48a or lower border 50a. Each intersection of second row 16a 2  with a column 18a defines an approximately rectangular medial platform 64a m . Each intersection of first row 16b 1  or second row 16b 2  with a column 18b defines an approximately rectangular flanking platform 64b which approximately coincides with a segment of upper border 48b or lower border 50b. It is also noted that, in array 14a and especially in array 14b, each non-flanking (interior) vertex of a platform 64 is nearly coincident with a non-flanking vertex of the defining columnwise side of an opening 12. Looking at it another way, in array 14a, the opening 12a oct  vertices which join oblique sides 40, 42, 44 and 46 with columnwise sides 32 and 34 are nearly in alignment, in a rowwise direction, with the opening 12a hex  shorter rowwise sides 26a; in array 14b, the opening 12b hex  vertices which join oblique sides 28b and 30b with columnwise sides 20b and 22b are nearly in alignment, in a rowwise direction, with the opening 12b hex  shorter rowwise sides 26b. 
     It is emphasized that inventive practice is not limited to array 14a shown in FIG. 1 and array 14b shown in FIG. 2; nor is this invention limited to variations of array 14a and array 14b. In the light of this disclosure, the ordinarily skilled artisan should readily appreciate the application of inventive principles to various patterns of inventive arrays 14 which are markedly distinguishible from arrays 14a and 14b in one or more respects. For example, this invention admits of effectuation not only for hexagonal apertures and octogonal apertures but for a diversity of apertural shapes, e.g., rectilinear, curvilinear, or having indicia of both rectilinearity and curvilinearity. 
     To elaborate, it is seen that there are multifarious inventively &#34;thematic&#34; patterns of apertural arrays. Inventive apertural arrayal motifs can be manifested in terms of rowwise arrangement, columnwise arrangement, diagonal arrangement, type or types of apertural shapes, interrelationships among various apertural shapes, etc. Among the configurational parameters which can be varied by the inventive practitioner are one or more of the following: (i) the number of different types of apertural shapes; (ii) the characteristics of each type of apertural shape; (iii) the relative distribution of the apertural shapes; (iv) the number of rows of apertural shapes; (v) the number of columns of apertural shapes; (vi) the degree of obliqueness of the positively sloped diagonals; (vii) the degree of obliqueness of the negatively sloped diagonals. 
     The openings, according to this invention, can be characterized by rectilinearity, or curvilinearity or both rectilinearity and curvilinearity. For example, an inventive opening can be entirely rectilinear and hence polygonal, i.e., thus defining a closed plane figure bounded by three or more line segments, i.e., wherein three or more line segments are joined end-to-end; hexagons and octagons, for instance, are types of polygons. Or, an inventive opening can be partially rectilinear and partially curvilinear, e.g., substantially define a polygonal figure but have curvature at certain locations around the perimeter of the opening, such as at the vertices or corners where adjacent sides meet. Or, an inventive opening can be entirely curvilinear, e.g., generally define a polygonal figure but have varying degrees of curvature around the entire perimeter of the opening. 
     Reference now being made to FIG. 1B, FIG. 3 and FIG. 4, approximately vertical transverse bulkheads can be inventively provided along continuous, generally crosswise paths which circumvent one or more apertured areas of the deck. For example, transverse bulkheads, such as bulkheads 70 1 , 70 2 , 70 3  and 7 4  shown in FIG. 3 and FIG. 4, can be accommodated by following staggered paths, such as the respectively corresponding paths 71 1 , 71 2 , 71 3  and 71 4  shown in FIG. 1B. 
     FIG. 3 and FIG. 4 reveal cutaway perspectives of approximately half of ship 80, including the layout of an interior deck space. Ship 80 includes ship hull 82 and two decks, viz., top level deck 10a T  and bottom level deck 10a B . Top deck 10a T  has array 14a T  of hexagonal hatches 12a hex-T  and octagonal hatches 12 oct-T  ; bottom deck 10a B  has array 14a B  of hexagonal hatches 12a hex-B  and octagonal hatches 12 oct-B . 
     Port edge 54a T  of top deck 10a T  is shown to meet ship hull 82 at the hull&#39;s port side 84; similarly, port edge 54a B  of bottom deck 10a B  is shown to meet ship hull 82 at the hull&#39;s port side 84. It can be envisioned that starboard edge 52a T  of top deck 10a T  meets ship hull 82 at the hull&#39;s starboard side (not shown), and that starboard edge 52a B  of bottom deck 10a B  meets ship hull 82 at the hull&#39;s starboard side (not shown). 
     Each of transverse bulkheads 70 1 , 70 2 , 70 3  and 70 4  crosses each of decks 10a T  and 10a B  so as to partially bound three hatches in each deck. In relation to top deck 10a T , each transverse bulkhead borders upon part of each of two hexagonal hatches 12a hex-T  and part of one octagonal hatch 12 oct-T . Similarly, in relation to bottom deck 10a B , each transverse bulkhead borders upon part of each of two hexagonal hatches 12a hex-B  and part of one octagonal hatch 12 oct-B . 
     As perhaps best illustrated in FIG. 1B, transverse bulkheads 70 1 , 70 2 , 70 3  and 70 4  cross decks 10a B  and 10a B  so as to appear &#34;recessed&#34; or &#34;indented&#34; in the fore direction of ship 80. A &#34;mirror-image&#34; inventive embodiment can be readily envisioned wherein transverse bulkheads 70 1 , 70 2 , 70 3  and 70 4  are shown to cross each of decks 10a T  and 10a B  so as to appear &#34;recessed&#34; or &#34;indented&#34; in the aft direction of ship 80; mentally reversing the port and starboard sides of ship 80 shown in FIG. 3 and FIG. 4, for example, could achieve such a &#34;mirror-image&#34; visualization. The inventive possibilities are endless for arranging and configuring bulkheads in conformity with inventive apertural arrayal. Generally speaking, for inventive marine vessel embodiments wherein bulkheads are implemented, at least one bulkhead at least partially crosses each deck so as not to encroach upon any apertures. The bulkhead will circumvent any aperture which is in the vicinity of the bulkhead. Although the bulkheads are shown in FIG. 1B, FIG. 3 and FIG. 4 to partially bound at least one hatch in each deck, in inventive practice a bulkhead need not be contiguous with one or more apertures or portions thereof. The inventive requirement in this regard is that each bulkhead avoid or skirt the openings so as not to impinge on any opening. 
     As shown in FIG. 3 and FIG. 4, a portion of top deck&#39;s array 14a T  matches a portion of bottom deck&#39;s array 14a B  whereby hexagonal hatches 12a hex-T  are in approximate vertical alignment with hexagonal hatches 12a hex-B  and octagonal hatches 12 oct-T  are in approximate vertical alignment with octagonal hatches 12 oct-B . In other words, at least to some extent, array 14a T  is approximately &#34;correlative&#34; with array 14a B . A section of array 14a T  is shown to be congruous with a section of array 14a B . Depending on the inventive marine vessel embodiment, two or more different (e.g., successive) decks can be entirely or partially correlative in that one, some or all of the apertures of one deck are in approximate vertical alignment with one, some or all of the apertures of one or more other decks. 
     Approximately vertical longitudinal port side bulkhead 86 is shown provided along port side 84, between decks 10a T  and 10a B , so as to approximately join upper border 48a T  of array 14a  T  with upper border 48a B  of array 14a B . Another longitudinal bulkhead, the starboard side counterpart (not shown), can be envisioned as disposed between decks 10a T  and 10a B  so as to approximately join lower border 50a T  of array 14a T  with lower border 50a B  of array 14a B . Some inventive marine vessel embodiments feature longitudinal bulkheads, such as depicted in FIG. 3 and FIG. 4, on each of the port and starboard sides. Such longitudinal bulkheads, which approximately coincide with the upper and lower arrayal borders of each of correlative plural decks, afford a &#34;double hull&#34; type of structural reinforcement, which is especially propitious where disposed in the vicinities of populated deck areas. 
     Other embodiments of this invention will be apparent to those skilled in the art from a consideration of this specification or practice of the invention disclosed herein. Various omissions, modifications and changes to the principles described may be made by one skilled in the art without departing from the true scope and spirit of the invention which is indicated by the following claims.