US 3623444 A
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United States Patent lnventor Thomas G. Lang 5354 Calle Vista, San Diego, Calif. 92109 Appl. No. 20,204 Filed Mar. 17, 1970 Patented Nov. 30, 1971 HIGH-SPEED SHIP WITH SUBMERGED BULLS Primary h'xaminerAndrew l-l. Farrell Anorneys- Richard S. Sciascia, Ervin F. Johnston and Thomas G. Keough ABSTRACT: A high-speed ship is formed of at least one elongate hull section submerged completely beneath the water's surface supporting a platform above the surface waves by a plurality of struts dependent from the platform to provide support and stabilization by reason of their configuration and location. High-speed dynamic pitch stability is ensured by including a stabilizer member on the aft portion of the submerged hull having a horizontally oriented control surface sufficiently sized to locate the greatest composite, vertical pressure surface substantially aft of the ships centroid. Controlling the angle of the stabilizer member in accordance with changing wave conditions and speed provides a highly stable cargo transport capability as well as superior weapons platform.
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THOMAS G. KEOUGH ERVIN F. JOHNSTON A TTORNEYS PATENTEBHUV 30 I9?! 3 523 444 SHEET 7 [IF 9 V j m H6. 53 94 7&5? 95 INVENTOR. 9o THOMAS e. LANG THOMAS G. KEOUGH ERVIN F JOHNSTON ATTORNEYS PATENTEDuuv 30 l97l SHEET 8 OF 9 INVENTOR.
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THOMAS G. LANG THOMAS G. KEOUGH ERVIN F. JOHNSTON ATTORNEYS HIGH-SPEED SHIP WITH SUBMERGED HULLS 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 In relatively calm seas, conventionally designed ships attain a rate of speed satisfactory for most requirements. As higher speeds are called for, wave drag and water surface drag impose maximum speed limitations. As the sea state varies, or more precisely, as increased wave activity is encountered, speed and stability of surface ships fall off markedly due to their inherent pitch, heave, and roll tendencies. One wellknown way of avoiding wave drag to achieve higher speeds is to construct a submarine configured ship having a large sized hull portion disposed beneath the surface of the waves with some sort of a control tower extending above the water's surface. Another approach for increasing speed by limiting water surface drag is to employ a pair of shallow draft, semisubmerged hull portions in a catamaranlike fashion supporting a platform above the surface of the water. While, in part, these designs have been successful, they have not eliminated the major speed and stability reducing limitations, that is, at high speed under adverse sea conditions, dynamic pitch, heave, yaw, and roll motions are not checked by the aforementioned designs. One attempt at damping these objected-to motions combines the previous teachings by separating a pair of submerged hulls, catamaranlike fashion, by a rectangular crossmember extending between the submerged hulls their entire length. However, as is readily apparent, the effect of such a manner of construction is to magnify pitching and heaving motions at high speeds in high-sea states since the aggregate of the total, vertically reacting, stabilizing control surfaces, provided by the crossmember, is forward, or at best, at the ships centroid. To elaborate, wave action causing upward or downward pressures ahead of, or near to, the centroid magnifies pitch and heave. Another endeavor to achieve high-speed stability modifies a single, bulbous submerged hull with a pair of dihedrally oriented struts supporting a control room above the surface of the water and with a pair of nominally sized fins carried on the rear of the hull. Although the small fins provide a marginal vertically reacting stabilizing surface, the aggregate of the vertically reacting control surfaces is substantially at the centroid of the vessel and high-speed dynamic pitch, roll, and, in particular, yaw remain an obstacle to acceptable performance. The state of the art does not ensure the markedly improved dynamic stability achieved by including a large horizontally oriented stabilizer on the aftmost extension of submerged hull portions, hydrodynamically functioning in much the same manner as do the vanes or feathers which aerodynamically stabilize the flight of an arrow.
SUMMARY OF THE INVENTION The present invention is directed to providing a high-speed marine vessel having improved static and dynamic stability including a platform member and an elongate, submerged buoying means interconnected by at least two water surface piercing strut members. The strut members are disposed with sufficient lateral spacing to ensure partial stability and with a sufficient longitudinal reach to provide additional stability and are configured in accordance with basic hydrodynamic design considerations. Mounted on the elongate buoying means, a horizontally oriented stabilizer sized to ensure the location of the greatest vertically reacting control surface aft of the centroid of the vessel, greatly increases the stability of the marine vessel irrespective of the relative speed or surrounding sea state.
Therefore, it is the prime object of the invention to provide a marine vessel having superior dynamic stability over wide ranges of speed under adverse sea states.
Yet another object is to provide a horizontally disposed stabilizer sized and positioned to ensure the location of the vertically reacting stabilizing surface substantially aft of the vessel s centroid.
A further object of the invention is to provide a marine vessel having a submerged hull portion supporting a platform by struts configured to minimize surface wave reaction and to provide static pitch, heave, and roll stability.
Still another object is to provide a high-speed ship having angularly controllable flaps sized and positioned to ensure improved dynamic pitch, heave, and roll stability.
Another object is to provide a semisubmerged high-speed ship having submerged, selectively vented, horizontally disposed control surfaces to ensure immediate correction for pitch, roll, and heave motions at high speeds under adverse sea states.
Another object is to provide a pair of elongate hulls sufficiently laterally separated beneath the surface of the water supporting a platform with a plurality of struts, all being configured for minimal hydrodynamic drag and maximum hydrodynamic stability and separated by a laterally extending stabilizer carried between the hulls aft portions for markedly increasing dynamic stability.
Another object is to provide a high-speed ship having a high-speed burst capability by including a system for ejecting drag reducing polymers in a complete layer over a buoying submerged hull.
Still another object is to provide a high-speed ship having a hull portion disposed beneath the water surface including a plurality of ballasting chambers, upon the selective evacuation thereof, reducing the ship's draft to enable shallow water operation.
Still another object is to provide a high-speed ship having means for raising and lowering a platform section to provide both a further reduced draft and a variable silhouette.
Another object is to provide a high-speed ship configured to induce minimal hydrodynamic turbulence making the ship adaptable for use as a relatively silent sonar platform.
Yet another object is to provide a high-speed vessel having the dynamic and static stability to ensure reliable delivery of ordnance.
An ultimate object of the instant invention is to provide a large stable platform having an aircraft accommodation capability formed from a plurality of the high-speed ships.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an isometric view of a preferred form of the invention in high-speed, dynamic pitch, heave, and yaw stability.
FIG. 2a is a schematic top view taken along lines 2-2 in FIG. 1.
FIG. 2b is a schematic top view generally taken along lines 2-2 in FIG. 1 showing high-speed yaw correction.
FIG, 2c is a schematic top view taken along lines 2-2 in FIG. 1 also showing yaw correction.
FIG. 3a is a schematic top view taken along lines 3-3 in FIG. 1.
FIG. 3b is a schematic view generally taken along lines 3-3 in FIG. 1 showing pitch correction.
FIG. 3c is a schematic view taken along lines 3-3 in FIG. 1 also showing pitch correction. FIG. 4a is a top depiction of a variation of the rearwardly disposed stabilizing means.
FIG, 4b is a top depiction of another variation of the stabilizing means.
FIG. 5a is an isometric view of a stabilizer means having a single variable angle flap portion for imparting dynamic pitch correction.
FIG. 5b is an isometric view of a stabilizer means having an aileron capability for imparting dynamic pitch and roll correction.
FIG. 5c is an isometric depiction of a vented stabilizer means.
FIG. St! is an end view of the stabilizer means taken generally along line Sde-Sde in FIG. 50. showing the creation of a vertically exerted, pitch stabilizing force.
FIG. Se is an end view of the stabilizer means taken generally along line 5de5de in FIG. 50 showing the creation of a counterclockwise exerted, roll stabilizing force.
FIG. 5f depicts uninterrupted waterflow over a vented hydrofoil taken along line Sf-Sf in FIG. Scl.
FIG. 5f depicts creation of a downward lifting force over a vented hydrofoil taken along line Sf-Sf in FIG. 5c.
FIG. 6 is a bottom view of a modified form of the invention additionally including a forwardly located lateral vane and a longitudinally extending storage pod.
FIG. 6a is a variation of the embodiment shown in FIG. 6 having a pair of delta-shaped vanes in place of a single forward vane.
FIG. 7 is a side view of the invention showing the longitudinal location of the ballasting chambers, water level sensors, and the viewing ports.
FIG. 8 is a cross-sectional view of a nose section of one of the submerged hulls schematically showing a polymer ejection system.
FIG. 9 is a front view schematically depicting an optionally included variable height platform.
FIG. 10 is an alternate form of the preferred embodiment.
FIG. 11 is a frontal view of a variation of the preferred embodiment of the invention showing a smaller platform supported by angularly disposed struts.
FIG. 12 is a side view of a variation of the invention having only a single, elongate hull.
FIG. 14 is a frontal view of the variation set forth in FIG. 12.
FIG. I3 is yet another variation having the supporting strut depending from the platform to the aftmost extension of the elongate hull.
FIG. 15 sets forth still another embodiment having a pair of dihedrally oriented aft struts.
FIG. 16 is a frontal view of the embodiment set forth in FIG.
FIG. 17 is a top view of several marine vessels secured together to form a large stable platform.
FIG. 18 is a frontal view of the stable platform shown in FIG. 17.
FIG. 18a is a frontal view of a modified large stable platform.
FIGS. 19(11), (b), and (c) are typical types of hydrofoils employed in the construction of the invention to minimize drag and turbulence according to the overall design requirements of the vessel and the conditions expected to be encountered.
FIG. 19(d) depicts creation of a lifting force by a fully wetted hydrofoil.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Marine designers have long known that surface wave drag as well as high-sea states severely limit the maximum speeds and stability of oceangoing vessels. Thus, a ship's efficiency, a scalar function of the product of displacement and maximum speed divided by the installed power, sharply falls off as surface wave drag is intensified by high-sea states.
Realizing this, the current state of the art shows semisubmerged ships that reduce, to some extent, a ships surface wave drag and static reaction to increasing sea states by locating substantially all of the bulky, heavy machinery, fuel, supplies, etc. in a hull section beneath the surface of the water as far as practically possible since wave action caused by increasing sea states diminishes exponentially as the depth below the surface increases.
However, merely locating a bulky hull beneath the surface of the water does not, by itself, materially provide for increased dynamic stability, especially at high speeds in high-sea states.
The configuration of the present invention ensures highspeed stability by strategically locating hydrodynamically designed struts and stabilizers. In the preferred form depicted in FIG. 1, a pair of essentially tubular-shaped parallel submerged hulls 40 and 50 provide a buoying support for a platform hull 20 through four vertically extending struts 30, 31, 32, and 33.
Each of the hulls is formed in the shape of a torpedo and advantageously incorporates the advancements of this particular technology, for example, choice of the optimum width-tolength ratios, weight distributions, power plant requirements, etc. Hulls, having a circular cross-sectional area, are selected as being the most suitable since this shape best resists water pressure when the hulls are submerged several hull diameters below the surface, although other shapes are optionally used.
Individual propellers 4| or 51 are connected through a suitable transmission to individual power plants to provide the forward and reverse thrust for locomotion and a rudder member 41a or 510 is carried immediately aft each screw to ensure a responsive means for controlling the marine vessel's heading. In the alternative to having a massive transmission connected to each of the propellers, they are of a variable pitch type enabling bidirectional thrust. In either case, the blades are optionally streamlined blades, base-vented blades, or super-cavitating blades depending on the cruise, operational, and dash speeds desired. Although not shown in the drawings, a pair of counterrotating propellers is included in lieu of each single propeller, or a hydrojet propulsion nozzle is carried on the aftmost end of each hull for propulsion and steering purposes.
By mounting the rudders in line with the variable pitch propellers, the marine vessel has a selective 360 vectored motion capability while substantially at rest and while maintaining a preestablished heading. With such a capability, cargo and passenger transfer operations are facilitated as well as where a precise hovering control is required to negate drift attributed to ocean currents.
Platform 20, depicted in FIG. I, has a typical commercial superstructure for storing materials or supplied and, because of its large flat area and inherent stability, includes a helolanding pad. The platfonn is constructed with watertight bulkheads, this being especially desirable when modified for military applications to provide emergency flotation if the elongate hulls become damaged or ruptured. At this point, let it suffice to say that the platform is fabricated to provide crews quarters, storage holds, ordnance mountings, etc. in accordance with sound shipbuilding practices. Novel modifica tions of the platform will be pointed out later in the specification.
The supporting struts are in keeping with contemporary strength of materials and hydrodynamic design criteria while providing a minimal drag and noise producing turbulence. FIG. 19 sets forth three representative sets of hydrofoils which are used as guides in fabricating struts 30, 31, 32, and 33 to minimize drag and noise-producing cavitation.
Cavitation is characterized by the formation of small cavities filled with water vapor which appear and collapse in the low-pressure region of a hydrofoil surface. As cavitation increases, there is a corresponding increase in the number and degree of such undesirable noise characteristics such as noise, drag, surface pitting, reduction in the lift, and unsteady performance. Cavitation is avoided by reducing speed, in particular, but since a highly stable, high-speed marine vessel is the desired end, cavitation with its attendant noise, unsteady performance, and drag must be eliminated or brought within tolerable limits by the proper choice of hydrofoils.
The hydrofoils in set 19(a) shows streamlined, fully wetted hydrofoils having excellent performance characteristics, such as freedom from noise and drag, at speeds up to the beginning of cavitation, However, cavitation begins at moderate speed when these foils are surrounded by a nominal pressure. Fully wetted hydrofoil sections are quite satisfactory on the lower portion of the struts when the water depth causes a considerable ambient pressure to contain cavitation tendencies at higher speeds.
Other types are superventilated hydrofoils, see set l9(b). These hydrofoils operate with their surfaces entirely covered by a gas such as air or engine exhaust, except for their waterbreaking nose portions. Having the strut sides covered by the gas cavity reduces drag.
For sustained performance at high speeds, a third type hydrofoil, a base-vented hydrofoil, see FIG. 19c, feeds gas from the atmosphere, or from a centrally disposed duct, through a plurality of trailing vent ports to create a steady gas envelope adjacent to the trailing surface. The overall effect is to create a steady cavity of noncondensing, noncollapsing gas in contact with its surface to eliminate drag and nose produced by otherwise cavitating hydrofoils. Thus, a routineer is free to choose a hydrofoilhaving only one cross-sectional configuration or a composite hydrofoil suitably stressed for the speed ranges expected and tolerable noise. Since cavitation is more prone to occur at shallow depth where there is less ambient pressure, a vertical strut which varies from a streamlined strut at the bottom to a base-vented or fully vented strut at the top is a preferred form for very high-speed ships.
While struts composed of the three types of hydrofoils referred to above are selected primarily as a weighted product of strength, speed, and noise considerations, they all experience substantially identical, composite forces when passing through water. No resultant lateral force is created when the velocity of the ambient water fiow is equal on opposite sides and when the hydrofoil's angle of attack is parallel with the direction of waterflow.
Rotating a fixed hydrofoil angularly to cut across the direction of waterflow, schematically represented in FIG. l9(d) by waterflow arrows, creates a positive pressure area on the "upstream side of the hydrofoil nose portion, shown as signs, and further creates an area of lower pressure on the "downstream" side of the hydrofoil nose portion, indicated by the signs. Hydrodynamic engineers have mathematically and empirically established that a rigidly held hydrofoils center of pressure, under such flow conditions, is approximately one-quarter of the hydrofoils length behind its leading edge. Therefore, the area of high pressure on the upstream side of the hydrofoil and the area of low pressure on the downstream side of the hydrofoil additively create a lifting force, represented by the large arrow LIFT in FIG. l9(d), on the hydrofoils center of pressure.
Thus, irrespective of the use of the hydrofoil, as a strut or as a stabilizer, laws of hydrodynamics dictate that substantially identical forces are created, the controlling factors being the velocity and the angle of impingement of the surrounding water.
Conventional ships as well as catamaran-type ships experience random forces which initiate yawing motions. These forces arise from wave and wind action as well as the water mediums reaction to the ship's propulsion plant.
A close examination of FIGS. 2a, 2b, and 2c shows how the strategically located struts eliminate yaw. By looking downward below the platform, the ship's centroid, or center of gravity, 25, is located in the same lateral plane as are main supporting struts 30 and 31.
In calm seas with no lateral forces applied, as the marine vessel travels at high speed in the direction indicated by the arrow in FIG. 2a, no clockwise or counterclockwise yawing motions about centroid 25 are experienced. Wave and water surface drag on the vertically extending pressure surfaces, forming the lateral surfaces of struts 32 and 33, produce equal and opposite, self-cancellingv moments about the centroid and the ship's heading remains constant.
A possible yawing action, caused by wind and waves, imparts a greatly exaggerated clockwise rotation, shown in FIG. 217. With the ships direction of travel as indicated by the large arrow, the passage of the struts through the water causes differential pressures to be built up along the vertically extending pressure surfaces forming on the lateral sides of all the struts. Forces, created by the angularly impinging water, represented by subarrows 30a and 31a on struts 30 and strut 31, respectively increase the clockwise yawing rotation. However, a yaw-correcting, counterclockwise moment is produced by forces exerted on the trailing struts 32 and 33, schematically represented by subarrows 32a and 33a. The initial clockwise yawing motion, augmented by the clockwise moments produced by forces generally indicated at 30a and 31a, is overcome by the much greater counterclockwise moments produced by forces 32a and 33a acting on struts 32 and 33. These latter forces, 32a and 33a, are transferred through a lever arm reaching from the struts to the centroid to create a yaw-correcting counterclockwise moment greatly in excess of the opposing torsional forces. Thus, the marine vessel automatically realigns itself in the direction of travel indicated by the large arrow.
In a similar manner, the marine vessel self-initiates the automatic correction of a counterclockwise yawing motion, shown greatly exaggerated in FIG. 2c. A counterclockwise torqueproducing force acts on struts 30 and 31, noting subarrows 30b and 31b, and tends to increase counterclockwise yaw. Rapid realignment of the marine vessel to its arrow direction of travel results from additive clockwise moment-producing forces, generally indicated by the subarrows 32b and 33b, which rotate the ship in a clockwise direction. Because of the lengthy lever ann reaching between the centroid and vertical pressure responsive surfaces on struts 32 and 33, the yaw correcting forces, in this case clockwise moments, quickly overwhelm the opposing moments to realign the vessel.
The rapid realignment of the marine vessel is owed to the strategic mounting of the vertical struts to locate the aggregate, rotation imparting, horizontally exerted pressure surfaces aft of the marine vessels centroid to ensure high-speed dynamic yaw stability.
Inherent yaw correction is present in an alternate form of the preferred embodiment, depicted in FIG. 10, having a single, longitudinally extending strut 34 or 35 extending from each hull to support the platform. Here again, the aggregate, vertically extending pressure surfaces, the sides of the struts 34 and 35, are disposed to ensure the location of the aggregate, horizontally exerted pressure surfaces aft of the vessels centroid 25a, noting that the leading edges are backward near the lateral projection of the vessels centroid. Having a pair of struts joining each hull to the platform, as depicted in the FIG. I embodiment, allows better maneuverability than the FIG. 10 configuration since the forward struts act like a keel and undergo smaller angles of attack in turns which reduces drag and lessens the tendency to cavitate. Also, the smaller surface area cutting through the waves reduces wave and frictional drag, and reduces the vessels wave response.
The lateral, cross-sectional schematic representation of the marine vessel of FIGS. 3a, 3b, and 30 gives insight into how the vessels superior, high-speed, dynamic pitch stability is achieved by a substantially horizontally oriented stabilizer 60. While the drawings show the stabilizer reaching between and somewhat forwardof the aftmost end portions of the hulls, the stabilizer is optionally located at any longitudinal position behind the centroid 25; however, the greatest stabilizing force is created when the stabilizer is carried between the aftmost end portions of the hulls.
The stabilizer, in its least sophisticated form, is a rigid member having an overall rectangular shape secured at opposite ends between the two parallel elongate hulls. The crosssectional configuration of stabilizer 60, optionally, is no more than a rectangularly shaped vane, but preferably is one of the hydrofoils set forth in FIG. 19. During operational speeds below that at which cavitation occurs, the fully wetted hydrofoils shown in FIG. l9(a) are best because of their low drag and low noise. When high speeds are anticipated, basevented hydrofoils shown in FIG. 19(0) are employed to reduce drag and noise. Irrespective of the cross-sectional configuration, stabilizer 60 is fabricated to provide additional structural rigidity between the aftmost portions of the hulls and to effectively transmit upward and downward forces to stabilize the vessels attitude.
In FIG. 3a a ship, traveling at a high rate of speed through a relatively calm sea, maintains a level attitude in accordance with predetermined ballasting and trimming with little or no rocking motions about the lateral projection of centroid 25.
When the ship encounters high-sea states, the vessel experiences pitching and heaving tendencies, shown greatly exaggerated in FIG. 3b for the purposes of explanation. The bow of the vessel is pitched upward and the stem is plunged downward by a bow-on, the combined motion defining a clockwise angular displacement generally about the centroid 25. The crest 26 of the wave submerges a much greater por tion of strut 30 and strut 31, the latter not shown, producing a buoying, upward pitching force on the bow. The trough of the wave, indicated by reference character 27, laterally contains the parallel rear struts 32 and 33, 33 not being shown, and causes an additive clockwise dipping motion generally about centroid 25. The clockwise motion is, in turn, augmented by another rotational force, generally shown as subarrows 30c, created as flowing water bears against strut 30 as it is being plowed deeper into wave crest 26.
With the direction of travel generally indicated by the large arrow, a vertical heaving force additionally is created by water pressure exerted on the submerged hulls, schematically represented by subarrow 50a, as the vessel travels through the water. This heaving force is a composite force substantially the same as the LlFT" force shown in FIG. 19(d), having a first component generally attributed to a positive upward pushing force exerted by the water on the lower half of the rounded nose section of each hull. The other component is attributed to a lifting force produced as the waterflow velocity is increased over the upper half of the rounded nose section of each hull creating an area of lower pressure, or a negative pulling force. Together, all the components impart a combined upward heaving motion and pitching motion.
Due to the unique configuration of the instant invention, the aforedescribed pitching and heaving motion normally experienced by, for that matter, any oceangoing vessel traveling at a high rate of speed through high-sea states, is dampened and nullified by the reacting forces acting on substantially horizontally oriented stabilizer 60.
As the vessel travels through the bow-on wave in the direction indicated by the large arrow, a vertical lifting force due to impinging water and indicated by subarrow 60a is generated on stabilizer 60, to rotate the entire marine vessel generally about centroid in a counterclockwise direction. Rotation in the counterclockwise direction relieves waterflow pressure from the nose portions of the hulls to eliminate the upwardly heaving force and, simultaneously, the pitching motion of the vessel, its previous clockwise motion, is also negated.
In the opposite extreme, when the bow dips into a wave trough following a bow-on wave as depicted in FIG. in a greatly exaggerated excursion, immediate compensation again begins by the rearwardly mounted stabilizer. The bowdipping-pitching motion is augmented by water fiow pressure, represented by subarrow 50b, pushing downward on both the hulls creating a sinking motion. Struts 30 and 31, now being in trough 27 and aftstruts 32 and 33 being on crest 26 of the wave, generate a generally additive counterclockwise dipping, pitching motion about centroid 25. Stabilizer 60 immediately rectifies the sinking and pitching tendencies of the vessel to ensure stable high-speed operation by its reaction to downward force 60!) produced as water flows over it. This downward force exerts a clockwise torque about centroid 25 that is much greater than the counterclockwise, pitch-producing forces, due to the fact that the force is transmitted about the centroid through the considerable longitudinal lever arm extending from the stabilizer to the centroid. Thus, correction for a simultaneous, bow-dipping, pitching motion and sinking motion immediately commences. When the vessel encounters following seas, the sequence depicted by FIGS. 3b and 3c is reversed but with substantially the same hydrodynamic stabilizing forces involved.
In conclusion, superior stability is ensured in dynamic yaw by the relative size and location of the vertically extending struts 30, 31, 32, and 33, and superior dynamic heaving and pitching stability is provided by a horizontally oriented stabilizer 60, to respectively place the aggregate vertically oriented stabilizing surfaces and horizontally oriented stabilizing surfaces substantially aft of the vessel's centroid to function in much the same, if not identical, manner as do the vanes or feathers stabilize the trajectory of an arrow.
Static stability, freedom from pitching, heaving, and rolling motions while the vessel is at rest, is also optimized by the configuration and spatial orientation of struts and hulls with respect to the platform. The transverse spacing of the struts and their fore and aft reach are designed using conventional engineering formulas to provide static stability. Because of the hulls considerable mass coupled with their being disposed more than one hull diameter beneath the surface of the water and separated a distance equal to several hull diameters, reaction to surface wave action is small when the vessel is at rest.
A slight tendency to pitch and roll is created by the waves buoying alternate ones of the struts. This tendency is reduced in the preferred embodiment, already described, by shaping the struts with cross-sectional areas in the form of one of the hydrofoils schematically represented in FIG. 19, to present a low-surface wave drag and to reduce the vessels power-consuming wave making drag. The cross-sectional areas are designed to ensure static stability and structural rigidity yet displace a minimum volume of water to reduce unstabilizing buoying forces when the struts become more or less completely immersed in water with respect to each other. Considering, therefore, the total volumes of all the struts piercing the waters surface and their relative lateral and longitudinal spacing, it is obvious that surface wave reactions are small when, for example, the volume of change in strut displacement due to fluctuating waves is small.
lf slight pitching and rolling motions are created by the waves, the relatively broad horizontally projected surfaces of stabilizer 60 and hulls 40 and 50 inertially produces opposing, damping forces. Thus, having a large sized, rearwardly mounted stabilizer, in addition to ensuring superior dynamic stability, also helps to maintain static stability.
As alternates to the basic rectangular, horizontally oriented stabilizer 60, FIG. 40 sets forth a pair of opposing delta-shaped stabilizing fins 60c and 60d mounted on either side of the aftmost extensions of each of the hulls, although these fins are optionally carried on the outside of the hulls extending in opposite directions. Still another modification of the stabilizer takes the form of pairs of diametrically opposed double deltas 602 and 60f, shown in FIG, 4b, carried on each of the hulls for increasing the stabilizer effect as well as permitting greater reliability due to redundancy of stabilizing surfaces.
One of the drawbacks of having a completely rigid stabilizer becomes apparent when it is noted that correction of the vessels attitude follows the vessels becoming slightlyoff course; that is, with respect to dynamic pitching upward and downward motions, stabilizing forces exerted on the stabilizer result from the vessels experiencing a pitching motion befo rehand. it is obvious, therefore, that providing a means for anticipating, or immediately monitoring, wind and wave conditions to accelerate and augment the production of counteracting stabilizing forces by the stabilizer results in a more stable oceangoing vehicle.
Looking ahead to FlG. 7, a means for anticipating ambient conditions takes the form of a source of command-control signals, schematically represented by a block 69 carried on the platform. The source is, for example, electrically switched representations of a helmsmans observations or attitude indications coming from a gyro-stabilized navigational device fed to a command-control lead 69a,
If automatic sensor signals giving indications of ambient wave conditions are desired, sonar, radar, or light sensors 70 are mounted at longitudinal and lateral extremes of the hulls and platform to provide sensor signals representative of relative variations in the waters surface with respect to the location of the sensor. The sensor signals are fed from each of the sensors, via lines 70a, to a centrally located common command-sensor control center 71 to generate and couple appropriate driving signals from the center to a drive-control lead 71a.
The common command-sensor control center, responsive to either command-control signals or sensor signals, is, in its simplest form, a visual readout interpreted by an operator who, by electromechanical linkages, switches the proper driving signal to drive-control lead 71a. Although, there is a time lag between initiation of the command signals or sensor signals, and the transfer of the proper driving signal, such an arrangement is adequate to provide responsive control of a large marine vessel in moderate seas. However, well-known automatic computerlike devices or any of a number of servocontrols contemporarily widespread are preferably adaptable to deliver a responsive driving signal upon receipt ofa discrete command or sensor signal. Due to the fact that these computerlike devices and servocontrols are universally known and employed, detailed examples are omitted in the specification for the sake ofsimplicity.
In FIG. a, improved control of the dynamic pitch, heave, and roll tendencies of the marine vessel is provided by modifying stabilizer 60 with a single, elongate flap portion 61 carried on its trailing edge. Two rotation imparting mechanisms 62 are separately secured at opposite ends of the flap and are responsive to driving signals appearing on drive-control lead 71a to impart a representative angular displacement to the flap. In the alternative, stabilizer 60 and flap 61 are constructed as an integral unit with the shaft extending through and journaled in the rotation imparting mechanisms 62 to be rotated as an entire unit to correct pitching motions.
A more preferred mechanism for controlling the dynamic pitch tendencies of the marine vessel while having a simultaneous capability for controlling the dynamic roll tendencies of the vessel calls for conventional fixed horizontally oriented stabilizer 60 having a pair of aligned aileronlike flaps 63 and 64. These flaps are carried on the trailing edge of the stabilizer in a coplanar relationship and are individually controllable by a separate rotation imparting mechanism 620 or 621), see FIG. 5b.
When underway in bow-on or following seas, signals originating in source 69 or sensors 70 are passed through the leads 69a or 70a to center 71. Appropriate driving signals are generated to actuate the independent rotation imparting mechanisms 62a and 62b. The aileronlike flaps 63 and 64 are rotationally displaced, simultaneously, to function like an elevator (identical to the operation of flap 61).
While turning, or when in beam or quartering seas, the vessel exhibits a tendency to roll in addition to experiencing pitching and heaving forces. Under these conditions, the aileronlike flaps are angularly displaced oppositely producing a counteracting banking rotational force since the laterally separated sensors 70, or source 69, pass signals to center 71, to indicate that the ship is canted or the surface of the water is higher on one side than on the other.
In a beam sea, independent counteracting driving signals are fed to the rotation imparting mechanisms and opposite angular displacements are imparted to the aileronlike flaps to maintain roll stability.
In a quartering sea, sensor output signals cause the generation of driving signals in the center driving the mechanisms to rotate the flaps in a simultaneous aileron and elevator fashion to stabilize the vessel with respect to the surrounding conditions.
During high-speed operation, severe stresses are developed within mechanically rotatable flaps when immediate, violent dynamic pitch, heave, and roll compensations are demanded. In speeds over 35 knots, nonreinforced flaps and their rotation imparting mechanisms are prone to fail, such failure possibly having disastrous results, especially in high seas. When the mechanically displaceable flaps are strengthened to withstand ill high-speed operation, the weight and cost of bearings and suitable journaling mechanisms have been found to be prohibitive.
Thus, it is that a third structure of maintaining high-speed dynamic stability in the instant marine vessel has been devised and is set forth in the stabilizer depicted in FIGS. 56, 5d, 58, 5f, 5/, and 5g.
A low cost, highly reliable controllable stabilizer is provided including two lined columns of vents 65 disposed on the dorsal and ventral sides of the horizontally oriented stabilizer. Onehalf of each of the vent columns is joined by a common lateral passageway connecting them in groups in common fluid communication with each other. Noting in particular FIGS. 5d and 5e, lateral passageways 66c and 66f, are each connected to one-half ofa separate column of upwardly facing vents on the left side of the stabilizer, and passageways 66g, and 6611 are connected to separate columns extending one-half the distance across the ventral side of the stabilizer. In a mirror image of the stabilizer's left side, the right side has passageways 66e' and 66]" linking columns of vents disposed on the stabilizers upper surface and passageways 66g and 66h joining downwardly facing vents on the right hand of the stabilizer.
In each hull 40 or 50, a source of pressurized gas 66 or 66' is provided with outlet ducts 66a, 66b, 66c, and 66d, or 66a, 66b, 66c, and 66d, respectively, connected to feed metered volumes of pressurized gas to passageways 66e, 66f, 66g, and 6611, or 66s, 66], 66g, and 6611'. Each of the sources of pressurized gas is a conventional air compressor, bank of compressed gas bottles, or an equivalent potential source of gas capable of being immediately valved by a self-contained valving unit in substantial amounts to the dorsally and ventrally facing vents.
Upon receiving driving signals from center 71, via driving control lead 71a, suitable volumes of pressurized gas are valved through selective ones of the outlet ducts to their interconnected discrete traverse passageways and pressurized gas flows through the vents creating a trailing cone of air as the high-speed marine vessel passes through the water.
Observing the schematic representations of waterflow around vented stabilizer 60 in FIGS. 5f and 5], 5f shows uniform waterflow as long uninterrupted symmetrical flow a'rrows around the symmetrical stabilizer as it passes through water at high speed. Equal upward and downward pressure is exerted on the upper and lower sides of the forward edge of the stabilizer as schematically represented by the small +s.
However, when the driving signals valve pressurized gas through traverse passageways 66e and 66f, a trailing coneshaped volume of pressurized gas 66k is extruded through the vents and over the upper trailing surface of the stabilizer. Formation of the gas cone causes disruption of the aforementioned uniform waterflow and it assumes essentially the shape of the flow arrows in FIG. 5] creating a composite shown by downward force, the LIFT arrow. This composite force as mainly attributed to the area of low pressure, generally designated by the signs on the stabilizers leading lower edge and side, and the high-pressure area, generally designed by the signs disposed about the stabilizers leading upper edge and side. Similarly, an overall upward LIFT" force is created by valving gas through the ventrally facing vents.
Thus, when driving signals, indicating an attitude correction for pitching, are passed to both sources of pressurized gas 66 and 66', pressurized gas is valved through upper traverse passageways 66e, 66f, 66c, and 66]. A composite downward force is created, schematically represented by a large arrow in FIG. 511', by the pressurized gas valved through all the dorsally facing vents.
On the other hand, if driving signals indicate that an immediate counterclockwise roll-compensating force be provided by the stabilizer, then pressurized gas is selectively vented to the dorsally facing vents on the stabilizers left side and the ventrally facing vents on the stabilizers right side, noting that FIG. 5e shows the creation ofa counterclockwise moment by passing pressurized gas through passageways 66c and 66f, and 66g and 6611 to their fluidly communicating vents.
The vertically upward and vertically downward forces on the stabilizer are intensified when the entire trailing edge of the stabilizer is completely covered by an envelope of pressurized gas. However, a partial upward or downward force is electively generated by venting only one of the two parallel columns of vents on either side of the stabilizer when a lesser force is needed to ensure stability.
Directing attention toward FIG. in which both dorsal columns of vents are passing pressurized gas on the left-hand side while only the trailing column of dorsal vents passes pressurized gas on the right side, reveals that a simultaneous. composite downward force is exerted on the entire length of the stabilizer while a partial counterclockwise moment is created to enable simultaneous, compensating correction for a pitching motion and a rolling motion by the vented stabilizer.
As mentioned before, the advantage of having a stabilizer vented as opposed to including rotatable vanes resides in the fact that having no moving parts ensures inherent greater, higher reliability and immediate response. Thus, high speed maneuvering and attitude correction for a sustained period of time is provided when employing a vented stabilizer to allow a full-time operational capability for the superiorly designed marine vessel disclosed herein.
A marine vessel constructed in accordance with the above teachings with a displacement of 5,000 tons attains a speed of between and knots with conventional propellers and power plant. Higher speeds are reached by mounting gas turbines in the hulls driving sophisticated base-ventilated propellers or pumpjets for operation in sea states up to, and beyond, sea state 6. At present, there is no other surface vessel of this size capable of smooth, continuous operation in such a highsea state; conventionally designed ships must reduce their speed to a few knots in such seas simply to survive.
Modifying the horizontally oriented stabilizer in accordance with the teachings of FIGS. 4a, 5b, and gives the marine vessel a capability to weather sea states producing waves greatly in excess of the vessels overall height. The typical 5,000 ton displacement marine vessel, referred to above, has supporting struts of 50 feet in length. It naturally follows that in seas having waves less than 50 feet from crest to trough, the vessel can maintain a level attitude by appropriately controlling the stabilizer. However, when the sea states increase to galelike proportions, the controllable stabilizer is best used not to hold the marine vessel in a relatively level attitude, but is controlled to allow the vessel to ride over huge waves which would otherwise swamp it. Riding over huge waves is optionally controlled from a helmsman feeding appropriate driving signals through driving leads 71a or by sensor signals originating from the plurality of sensors 70.
Further control of the vessels heaving tendencies is aided by mounting a forwardly located control vane 68, see FIG. 6, on a shaft 68a journaled at opposite ends in separate rotation imparting, vane control mechanisms 68b. The vane control mechanism is controlled by driving signals, fed via leads 71a emanating from center 71 to angularly displace the control vane in a hydrodynamically cooperating relationship with horizontally oriented stabilizer 60. The angular displacement of the vane is coordinated with the rotation of flaps 63 and 64 to provide the desired heaving and pitching control forces and moments. For example, when extreme heave is encountered, both the vane and the stabilizer are simultaneously rotated in the same direction to produce a unidirectional upward or downward force to oppose the heave. On the other hand, when extreme pitching needs correction, the vane is angularly displaced in one direction to produce a pitch counteracting force while the stabilizer is rotated in the opposite direction to additionally help counteract the pitch. When no control force is needed by the vane, the vane is feathered to align itself with the waterflow so as not to interfere with the stabilizing action ofstabilizer 60.
The spatial disposition of the hulls coupled with their location a considerable distance beneath the surface of the water minimizes wave making and eddy noise and, accordingly, provides an ideal location for carrying backward-looking sonar, towed array sonar, towed whip sonar, or a housing for submersibles, ordnance, etc. A podlike fairing is mounted on the underside, or coplanar with the stabilizer, and, as shown in FIG. 6 is connected between stabilizer 60 and a traverse forwardly located control vane 68. Being mounted a distance below the surface is particularly desirable in miiitary operations, aside from noise considerations, since the package carried in pod 80 is not subject to scrutiny by distant observers. The fairing pod, when connecting the control vane to the stabilizer, is advantageously stressed to strengthen the structural linkages between the two elongate hulls and, of course, is streamlined to reduce drag and noise.
Modification of the forwardly mounted control vane in the shape of a pair of opposing delta-shaped control vanes 68. necessitates each being supported by a shaft journaled in a suitable rotation imparting control 68b receiving driving signals over individual driving leads 71a. The fairing pod optionally is joined to the delta-shaped control vanes; however, cantilevering the pod from the rear stabilizer is adequate, barring the creation of extreme stresses, note FIG. 60. As in the preceding example, the delta-shaped control vanes and the stabilizer have hydrodynamically coordinated angular displacements to enhance heave and pitch dampening.
Placing the twin hulls several hull diameters below the surface of the water gives the marine vessel a deep draft to prevent its entry into most harbors and preclude shallow water operation. In FIG. 7, ballasting chambers 20a and 20);, carried in the platform section, ballasting chambers 40a and 40b in hull40, and chambers 50a and 50b in hull 50, not shown, are included to permit their selective evacuation allowing the hulls to be buoyed to the surface of the water and enable shallow water ferrying of the vessel.
Further draft reduction is provided by adding a rack and pinionlike mechanism 22 and 23 to the struts and platform, noting in FIG. 9. In a first modification the pinion mechanism and its controlling machinery are carried on platform 20 in a dependent platform hull section 25 having a pair of longitudinal recesses 25a and 25b. Upon lowering the platform hull with the machinery driving the pinions downward along the racks, the lower portion of the platform hull section is brought in contact with the surface of the water and forced below. Forcing the hull section below the surface creates an additional buoying force further reducing the overall draft of the marine vessel. The longitudinal recesses are configured to conform to the rounded outer surfaces of both hulls 40 and 50 when the platform hull section has been fully lowered, platform hull section 25 shown schematically in FIG. 9 completely lowered, and in phantom, completely raised.
With platform 20 carrying a topmost flat portion 24, along with a dependent hull section 25, an elective modification is provided using the lifting and lowering capabilities of the rack and pinion mechanism. This modification permits the selective vertical displacement of the flat portion along with or independent ofthe hull section. Having the capability for raising and lowering the entire platform enables smoother cargo transfer operations when docks of different heights are encountered and, also provides a variable silhouette capability which, from a military standpoint, promises reduced vulnerability as well as facilitating camouflage and concealment.
Because the struts extending upwardly from the submerged hulls through the water's surface have only a minimal crosssectional area designed to provide a minimal surface wave drag and wavemaking drag, the maximum speed limitation on the marine vessel is generally stated as being a function of the propulsion plants power overcoming the water surface drag or frictional drag along the outside of the two submerged hulls.
Speed is markedly increased, as shown in FIG. 8, by providing a reservoir of water-soluble polymers 72 within each of the hulls and a valved source of pressurized gas 73, or similar mechanism for expelling a polymer layer 72a through a vented nose sieve 74. The valve 73a is actuated by an ejection signal appearing on lead 731) from center 71 and a polymer layer is ejected to cover the nose section and the longitudinal reaches of each hull greatly reducing the frictional drag and giving the marine vessel a high-speed burst capability with no increase in power plant output. Supplemental slots 75 along the hull, also operatively connected to the reservoir, ensure that the layer is not broken to keep down the frictional drag.
In the twin hull configuration of FIG. 10, inclusion ofa pair of forward looking sonars 76 and 77 in each of the nose sections of the hulls enables superior three-dimensional sonar resolution. In addition, a planar, conformal sonar 78 is ideally adaptable for mounting on the outside, outwardly facing submerged hulls. Both the forward looking and the conformal sonars permit highly accurate readouts since they are fixed on the relatively large hulls a considerable distance below the area of noise-producing surface waves and eddy vortex resulting in greater reliability in the composite sonar systems. Including a fairing pod 69 housing a towed sonar array or whip array along with forward looking sonars 76 and 77 and planar sonar 78 provides even greater resolution.
Forming a plurality of marine vessels with platforms having an essentially flat portion 24, schematically represented in FIG. 9, permits a modularlike construction of a single, large, stable floating platform 90, noting FIG. 17. Individual marine vessels are joined by a mechanism as simple as a large U- shaped bolt 91 inserted in vertically disposed bores provided in each of the fiat portions. Such a platform 90, thusly constructed, accommodates heavily loaded aircraft and supplies. If each marine vessel is outfitted to serve a particular function, for example, one vessel serving as a tanker while another is a command headquarters, crew quarters, supply depot, etc., the vessels can be separately deployed from widely separated supply points to rendezvous at a predetermined point for a combined operation. In the alternative of simply constructing a large stable floating platform from a plurality of the marine vessels, the platform is an integral member 900, see FIG. 18a, supported by struts anchored on elongate hulls 40 and 50, separated by a horizontally disposed stabilizer 60.
Employing the inventive concept of providing the submerged hulls with strategically spaced struts and a large horizontally oriented stabilizer located aft the vessel's centroid permits simple relocation of the struts to form the alternate embodiments shown in FIGS. 12 through 16.
In the embodiment of FIGS. 12 and 13, a single elongate hull 90, displacing an elliptical cross-sectional area, has a pair of essentially delta-shaped stabilizers 91 carried on the aft portion of the hull. The stabilizers are fixed or, if rotational, are linked to a suitable driving mechanism used in the previous embodiments, to eliminate dynamic pitch or heave. A single supporting strut 92 supports a platform 93 and a pair ofoutriggerlike water surface piercing struts 94 and 95 emplace the aggregate vertically oriented, horizontal pressure control surfaces substantially aft of the centroid of the vessel to eliminate yaw. Struts 94 and 95 are preferably base vented to aid in quiet high-speed operation and displace a sufficient volume of water to maintain lateral and longitudinal static stability. Since the large delta shaped stabilizer locates the vertical pressure exerting control surface considerably aft of the centroid, pitch, heave, and roll stability is guaranteed.
A side view of an alternate embodiment of the modification of FIGS. 12 and 13 appears in FIG. 14. An elongate hull 90a supports a platform 930 through a single strut 92a from its aft portion and a pair of forwardly located water surface piercing struts 95a and 940, the latter not shown, are laterally disposed with the same separation as struts 94 and 95 shown in FIG. 13. The total laterally exposed surface of rear strut 92a aft of centroid is considerably more than the wetted area of depending struts 95a and 94a (latter not shown) to stabilize the vessel in dynamic yaw. The horizontally oriented stabilizer 91a, being optionally fixed or controllable, ensures stability from dynamic pitch, heave, and roll substantially in the same manner as disclosed above.
In FIGS. 15 and 16, a single vertically extending strut 9211 supports a platform 93b from an elongate hull b. The strut supports the platform generally through the vessel's centroid 25, but a pair of dependent struts 94b and 95h reach down from rearward lateral extremes of the platform to form a dihedral angle at their juncture point on the hull. A pair of controllable flaps 94c and 956 are optionally included on the dihedral sections of the struts and, by an internal driving mechanism and sensors, the flaps are displaced to correct for pitching, heaving, and rolling tendencies of the vessel. Additional delta-shaped horizontal control vanes (not shown) may be mounted near the nose of the hull for augmented pitch and heave control. Here, again, consistent with the disclosed inventive concept of locating the aggregate horizontal control surfaces and the vertical control surfaces substantially aft of the centroid of the marine vessel, in the instant embodiment, the aggregate horizontal and vertical control surfaces are located substantially aft of the centroid by strategically locating the dihedral struts 94b and 95b, and, the dihedral portions mounting the flaps 94c and 950.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings, and it is therefore understood that within the scope of the disclosed inventive concept, the invention may be practiced otherwise than as specifically described.
What is claimed is:
l. A marine vessel having static and dynamic stability comprising:
a platform member;
two parallel elongate hulls operationally disposed below the level of surface waves laterally separated a distance equal to at least two hull diameters;
at least two water surface piercing strut members depending from said platform member, each hull mounting at least one of said water surface piercing strut members vertically supporting said platform member and each being longitudinally positioned to provide a strut member leading edge cutting said water surface forward of the centroid of said marine vessel and a strut member trailing edge cutting said water surface in substantially the same lateral vertical plane occupied by the aftmost extension of each hull, said strut members disposed a sufficient lateral spacing with respect to each other to provide in part said stability and with sufiicient longitudinal spacing having a strut leading edge separated from a strut trailing edge a distance at least equal to said lateral spacing to provide in part said stability, each of said strut members are shaped with a hydrofoil cross-sectional configuration designed for minimal wave and spray drag and being disposed with respect to one another to ensure that the aggregate dynamic centers of horizontally exerted pressure attributable to said strut members are located aft the centroid of said marine vessel to improve dynamic yaw stability and are longitudinally disposed to span a sufficient distance to provide static pitch stability; and
horizontally oriented stabilizer means operationally disposed below the level of surface waves mechanically coupled to both said hulls and sized and longitudinally disposed to ensure the creation of its dynamic center of vertically exerted pressure substantially aft the centroid of said marine vessel to further improve dynamic pitch stability.
2. A marine vessel according to claim 1 in which said horizontally oriented stabilizer means is a pair of cantilevered hydrofoils each secured to one of said hulls in an opposing relationship.
3. A marine vessel according to claim 1 in which said horizontally oriented stabilizer means is two pairs of cantilevered hydrofoils, individual ones of said pairs being oppositely mounted with respect to each other on separate ones of said hulls to ensure greater stability.
aligned hydrofoils are gularly shaped hydrofoil and said controlling means is a rotation-imparting mechanism responsive to command-control and servocontrol actuation to impart said angle variations.
4. A marine vessel according to claim 1 in which said horizontally oriented stabilizer means is an essentially rectangular shaped hydrofoil mounted between said hulls from one said aftmost extension to the other.
5. A marine vessel according to claim 4 further including:
a plurality of vents provided in oppositely facing surfaces of said rectangularly shaped hydrofoil; and
shaped hydrofoil; and
varying means including a source of pressurized gas selectively fed to said vents to induce a vertically reacting hydrodynamic stabilizing pressure on said rectangularly shaped hydrofoil.
6. A marine vessel according to claim 4 further including:
variable flap means associated with said rectangularly shaped hydrofoil in a coplanar relationship; and
means for controlling the angular disposition of said flap means including a flap control mechanism to restrain the pitch of said marine vessel.
7. A marine vessel according to claim 6 in which said flap means is a pair of aligned hydrofoils and said flap control mechanism has elements for imparting simultaneous, identical angle variations to said aligned hydrofoils giving them an elevator capability and simultaneous, discrete to said aligned hydrofoils giving them an aileron capability for controlling the dynamic pitch, heave, roll movements of said marine vessel.
angle variations 8. A marine vessel according to claim 7 in which said pivotally mounted adjacent said rectan- 9. A marine vessel according to claim 6 further including:
a control vane pivotally mounted between said hulls forward ofsaid centroid; and
the controlling means includes a vane control mechanism linked to said flap control mechanism to impart angle variations to said control vane hydrodynamically cooperating with said flap means to further minimize pitch, heave, and roll tendencies ofsaid marine vessel.
10. A marine vessel according to claim I further including:
a polymer reservoir internally disposed in each hull; and
means for ejecting drag reducing polymers in fluid communication with each said reservoir including a portion axially disposed on the foremost nose section of each said hull configured to ensure the ejection of a polymer layer over each said nose section and along the length of each said hull, upon said ejection permitting a reduced surface drag and ensuring a high-speed burst capability.
11. A marine vessel according to claim 10 further including:
a plurality of slots longitudinally disposed in each said hull in fluid communication with said polymer reservoir, upon said ejection, augmenting said layer along the entire said length further reducing said surface drag.
12. A marine vessel according to claim 1 further including:
ballasting chambers disposed in each said hull; and
means allowing the evacuation and flooding of all said ballasting chambers, upon said evacuation, said hulls are raised through said water surface to possess a significantly reduced draft enabling shallow water operation.
13. A marine vessel according to claim 12 further including:
a platform hull section included with and dependent from said platform member in a vertical projection distinct from the vertical projection occupied by both said hulls; and
means for raising and lowering said platform hull section, upon lowering said platform hull section to and through said water surface, further reducing its draft.
14. A marine vessel according to claim I further including:
means for raising and lowering said platform member with respect to said hulls giving said marine vessel a variable silhouette and cargo transfer capability.
15. A marine vessel according to claim I in which a first and a second strut interconnects each hull to said platform member, each said first strut IS mounted to provide vertical support in the lateral projection of said centroid and each said second strut is mounted to provide vertical support in the lateral projection of each said aftmost end, each said first and second strut is sized and configured to ensure location of the aggregate centers of horizontal pressure aft said centroid to enhance dynamic yaw stability,
16. A marine vessel according to claim I further including:
means for supporting marine vessels, such as submersibles,
fixed and towed sonar, on said horizontally oriented stabilizer means being disposed to laterally space said vessels from said hulls to ensure operation outside the turbulence created by the passage of said hulls.
17. A marine platform having static and dynamic stability formed of a plurality of marine vessels according to claim 1 and a plurality ofconnecting means joiningsaid marine vessels into said platform for providing a mobile, highly stable aircraft carrierlike platform and being readily separable to form a plurality of independent said marine vessels for simultaneously discharging independent duties.
18. A marine platform according to claim 17 in which said carrierlike platform is an integral structure.