Abstract:
A vessel designed to operate efficiently as both a catamaran and air cushion vessel can travel at low speed in a catamaran or displacement mode, high speed in an air cushion mode, and amphibiously with the aid of deployable side seals. The vessel includes catamaran hulls and flexible air cushion bow and stern seal systems together with retractable side seals having hinged doors containing inflatable, retractable flexible components. The doors form part of the side seal system in the deployed position, and protect the flexible components of the seal in the retracted position. The arrangement reduces the drag associated with the side seals while the vessel operates in its catamaran or surface effect ship modes, and prevents damage to the seals during operation in the high speeds SES mode.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Priority of US Provisional Patent Application No. 60/755,938, filed 30 Dec. 2005, incorporated herein by reference, is hereby claimed. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable  
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     Not applicable  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     The present invention relates to catamaran air cushion ships. More particularly, the present invention relates to an improved surface effect ship or air cushion ship with a catamaran hull having a folding side seal arrangement that features lockable hinged doors and an inflatable seal portion.  
         [0006]     2. General Background of the Invention  
         [0007]     In general air cushion vessels or ships, also known as surface effect ships, are known. Examples of air cushion vessels or ships disclosed in U.S. patents are listed in the following table. The following table also lists U.S. Pat. No. 6,619,220 that discloses a surface effect ship or hovercraft with a retractable skirt system.  
                       TABLE 1                               Date       US Pub. No.   Title   MM/DD/YYYY                   1,976,046   Waterfoil   Oct. 9, 1934       2,405,115   Floating Structure   Aug. 6, 1946       3,065,723   Supercavitating Hydrofoils   Nov. 27, 1962       3,077,173   Base Ventilated Hydrofoil   Feb. 12, 1963       3,141,436   Hydrofoil Assisted Air   Jul. 21, 1964           Cushion Boat       3,458,007   Captured Air Bubble (CAB)   Jul. 29, 1969           Ground Effect Machine       3,621,932   Gas-Cushion Vehicles   Nov. 23, 1971       3,917,022   Twin Cushion Surface Effect   Nov. 4, 1975           Vehicle       3,987,865   Gas-Cushion Vehicle Skirt   Oct. 26, 1976       4,469,334   Sealing System For The Air   Sep. 4, 1984           Cushion Of An Air-Cushion           Vessel       4,489,667   Surface Effect Ship Seals   Dec. 25, 1984       4,506,618   Propeller And Keel   Mar. 26, 1985           Arrangement For Surface           Effect Ships       4,535,712   Variable Air Cushion Mode   Aug. 20, 1985           Vehicle       4,543,901   Surface Effect Ship Air   Oct. 1, 1985           Cushion Seal System       4,646,866   Surface Effect Type, Side   Mar. 3, 1987           Keel Vessel Fitted With An           Improved Forward Buoyancy           Cushion Seal Apparatus       4,660,492   Catamaran Air Cushion Water   Apr. 28, 1987           Vehicle       4,708,077   Hull Shapes For Surface   Nov. 24, 1987           Effect Ship With Side Walls           And Two Modes Of           Operation       4,714,041   Structure of surface effect   Dec. 22, 1987           ship with side walls       4,739,719   Movable bow seal air ride   Apr. 26, 1988           boat hull       4,767,367   Integrated Combination   Aug. 30, 1988           Propeller Drive Shaft           Fairing and Water Intake           Sea Chest Arrangement, For           High Speed Operating Marine           Craft       5,651,327   Displacement, Submerged   Jul. 29, 1997           Displacement, Air Cushion           Hydrofoil Ferry Boat       5,711,494   Aero-Hydroglider   Jan. 27, 1998       5,934,215   Stabilized Air Cushioned   Aug. 10, 1999           Marine Vehicle       6,293,216   Surface Effect Ship (SES)   Sep. 25, 2001           Hull Configuration Having           Improved High Speed           Performance and Handling           Characteristics       6,439,148   Low-Drag, High-Speed Ship   Aug. 27, 2002       2003/0000440   Air Assisted Landing Craft   Jan. 02, 2003       6,526,903   High speed M-shaped boat hull   Mar. 04, 2003       6,609,472   Stable efficient air   Aug. 26, 2003           lubricated ship       6,619,220   Hybrid SES/hovercraft with   Sep. 16, 2003           Retractable Skirt System       2005/0211150   Variable Hybrid Catamaran   Sep. 29, 2005           Air Cushion Ship       2005/0236200   Wrapped-cone fingers for   Oct. 27, 2005           skirt systems       7,013,826   Hybrid Catamaran Air Cushion   Mar. 21, 2006           Ship                  
 
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a catamaran surface effect ship that has a catamaran hull having spaced apart hulls connected with a platform and an integral propulsion system for propelling the hull.  
         [0009]     The hull has forward and aft flexible seals and flexible side seals that enable pressurized air to be trapped in an air space that is positioned generally in between the hulls and in between the forward and aft flexible seals.  
         [0010]     The hull has a powered lift fan system for transmitting pressurized air to the air space.  
         [0011]     The side seal system for each hull includes a movable door that is movably (e.g. pivotally) attached to the side of each hull. An inflatable seal expands below the door and in between the door and the hull.  
         [0012]     Locking dogs (e.g. motorized) positively lock the doors shut when the side cushion is deflated. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0013]     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the attached drawings which are identified as follows:  
         [0014]      FIG. 1  is a perspective view of the preferred embodiment of the apparatus of the present invention;  
         [0015]      FIG. 2  is a perspective view of the preferred embodiment of the apparatus of the present invention;  
         [0016]      FIG. 3  is a sectional view taken along lines  3 - 3  of  FIG. 1 ;  
         [0017]      FIG. 4  is a sectional view taken along lines  4 - 4  of  FIG. 2 ;  
         [0018]      FIG. 5  is a schematic sectional, elevation view of the preferred embodiment of the apparatus of the present invention;  
         [0019]      FIG. 6  is a fragmentary perspective view of the preferred embodiment of the apparatus of the present invention;  
         [0020]      FIG. 7  is a fragmentary perspective view of the preferred embodiment of the apparatus of the present invention;  
         [0021]      FIG. 8  is a partial perspective view of the preferred embodiment of the apparatus of the present invention; and  
         [0022]      FIG. 9  is a perspective view from the stern of the preferred embodiment of the apparatus of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     The marine vessel  10  of the present invention is designed to operate as both a catamaran and air cushion vessel. The catamaran air cushion vessel of the present invention is designated generally by the numeral  10  in  FIGS. 1-9 . Marine vessel  10  has several advantages over previous air cushion and surface effect ship designs. Marine vessel  10  has a robust structure having sufficient strength to withstand sea, cargo and beach operation loads. Marine vessel  10  also is lightweight for speed, endurance and cargo capacity performance.  
         [0024]     Catamaran air cushion ship  10  is shown generally in  FIGS. 1-9  and includes port hull  11 , starboard hull  12 , bow  13  and stern  14 . Ship  10  may be constructed, for example, of high strength steel, aluminum, titanium, or composite materials such as fiberglass or carbon epoxy laminate.  
         [0025]     Platform  15  spans between and connects the port hull  11  and starboard hull  12 . The hull  12  is generally of the same configuration as the hull  11  of  FIGS. 3-5 . Platform  15  has a deck area  26 . Deck area  26  is capable of withstanding local pressures greater than 500 psf (0.244 kg/cm 2 ) from the carriage of wheeled or tracked vehicles.  
         [0026]     A forward seal  16  is provided at bow  13  and an aft or stern seal  17  is provided at stern  14 . At bow  13 , forward seal  16  can be in the form of a plurality of individual finger seals. Such seals  16 ,  17  can be seen for example in prior U.S. Pat. Nos. 3,621,932; 3,987,865; and 4,646,866 each hereby incorporated herein by reference. Forward seal  17  and stern seal  17  are capable of surviving high speed flow without significant impact on SES or Catamaran mode resistance.  
         [0027]     Each hull  11 ,  12  provides a curved bottom  18 , an outer side wall  19 , and an inner side wall  21 . The catamaran air cushion vessel  10  of the present invention can be scaled to a wide range of ship sizes, with overall length typically in the range of 100 feet to 1000 feet (30.5 m to 305 m), and beam in the range of 30 feet to 300 feet (9.1 m to 91 m). Cargo capacity will typically be 20% to 50% of full load displacement, which can range from 100 tons to 100,000 tons (90.7 metric tons to 90,700 metric tons).  
         [0028]     The air cushion ship  10  has multiple water propellers  20 , preferably a single water propeller  20  positioned at the stern of each hull  11 ,  12 . The air cushion ship  10  also provides air propellers  22  that extend upwardly from the port hull  11  and starboard hull  12  as shown in  FIGS. 1-2 .  
         [0029]     Inner side wall  21  is provided for each hull  11 ,  12  for enabling a cushion pressure (Pc) to be generated in between hulls  11 ,  12 , platform  15  and waterline  39  as shown in  FIGS. 3, 4  and  5 . Rudders can be provided at  23 ,  24  including port rudder  23  and starboard rudder  24  as shown.  
         [0030]     Platform  15  provides deck area  26  that communicates with bow ramp  27  and stern ramp  28 . Vehicles and/or cargo can thus be driven or towed to deck area  26  using either bow ramp  27  or stern ramp  28 . Likewise, vehicles, cargo and the like can be unloaded from the deck area  27  using either bow ramp  27  or stern ramp  28 . Superstructure  29  supports air propeller  22  and a pilot house  25 , crew quarters or the like.  
         [0031]     A folding side seal  30  is provided for each hull  11 ,  12 . The folding side seal  30  includes a door  32  that is movably attached to a hull  11  or  12  using for example hinge  31 . The cushion pressure air (Pc) can be transmitted to inflate folding side seal  30  by routing the pressurized air via channel  33  to the interior of the folding side seal  30 . Channel  33  can be valved using a valve  34 .  
         [0032]     Side seal  30  is capable of sustaining high speed flow without significant impact on SES or Catamaran mode resistance. The ability of side seal  30  to deploy and retract accommodates both SES and Catamaran modes of operation of marine vessel  10 .  
         [0033]     The folding side seal  30  includes a tension membrane  35  that extends between the bottom of each hull  11  or  12  and the lower end portion of door  32  as shown in  FIGS. 3-5  and  8 . The tension membrane  35  limits pivotal movement of door  32  to its maximum opening position of  FIGS. 2 and 4 . Arrow  55  shows door  32  opening in the outboard direction. Arrow  56  shows door  32  closing in the inboard direction.  
         [0034]     A fender  36  can be positioned above hinge  31  as shown in  FIGS. 1-5  and  8 . Inflatable fingers  38  extend below tension membrane  35  as shown in  FIGS. 3-5  and  8 . Fingers  38  can be generally u-shaped in transverse cross section. Such fingers  38  can be of the type shown for example in the patents that were incorporated herein by reference. Air cushion pressure (Pc) communicates with fingers  38  below hull  11  or  12 , extending them outwardly (see  FIGS. 3-5 ,  8 ). End webs  37  can be provided on each hull  11 ,  12  fore and aft the fingers  38 .  
         [0035]     An inflated position of folding side seal  30  is shown in  FIGS. 2, 4  and  8 . In  FIG. 4 , inflation is indicated by arrows  49  with air being transmitted from the space  48  that is under platform  15 , in between hulls  11 ,  12  and above waterline  39 . Arrows  49  illustrate the flow path of air as it travels to inflate the folding side seal  30 . During inflation of side seal  30 , locking dogs  43  are released, door  32  swings in the outboard direction  55  and fingers  38  are deployed/inflated.  
         [0036]     A closed, folded position is shown in  FIGS. 1 and 3 . During retraction/deflation of side seal  30 , air is removed from fingers  38 , repositioning locking dogs  43 , allowing door  32  to swings in the inboard direction  56 .  
         [0037]     In order to assist deflation of folding side seal  30 , a vacuum can be provided. The vacuum can be a venturi arrangement  54  that includes flow line  40 , valve  41  and a source of vacuum as indicated schematically by arrow  42  in  FIG. 5 . The vacuum  42  can be used to remove air from inflatable side seal  30 , though hydrostatic pressure will also help collapse and deflate the fingers  38 .  
         [0038]     Once deflated, the side seal  30  can be locked in a closed position using motor operated locking dogs  43 , each being powered with motor  44 . A locked position  45  is shown in  FIG. 3 . An unlocked, operating position  46  is shown in  FIG. 4 .  
         [0039]      FIGS. 3-5  illustrate inflation of seal  30 , partial inflation being shown in  FIG. 5  and complete inflation (operating ACV mode) being shown in  FIG. 4 . The full inflation position is indicated schematically by the numeral  47 .  
         [0040]     A drain arrangement is shown in  FIGS. 6-7  for preventing accumulation of water above tension membrane  35 . Opening  50  in tension membrane  35  allows water to drain from the upper surface of membrane  35  downwardly. A valving member  51  is mounted to the under surface of membrane  35  below opening  50 . Valving member  51  is attached to the underside of membrane  35  at attached edge  52 . Free edge  53  separates from membrane  35  when draining water from the upper surface of membrane  35  via opening  50 .  
         [0041]     The following is a list of suitable for the various elements of the preferred embodiment of the present invention.  
                                         PARTS LIST            Parts Number   Description               10   catamaran air cushion vessel       11   port hull       12   starboard hull       13   bow       14   stern       15   platform       16   forward seal       17   stern seal       18   curved bottom       19   outer side wall       20   water propeller       21   inner side wall       22   air propeller       23   port rudder       24   starboard rudder       25   pilot house       26   deck area       27   bow ramp       28   stern ramp       29   superstructure       30   folding side seal       31   hinge       32   door       33   channel       34   valve       35   tension membrane       36   fender       37   end web       38   finger       39   water level or waterline       40   flow line       41   valve       42   vacuum source - venturi arrow       43   motor operated locking dog       44   motor       45   locked position       46   unlocked, operating position       47   full inflation height       48   space       49   arrow       50   opening       51   valving member       52   attached edge       53   free edge       54   venturi       55   arrow       56   arrow                  
 
         [0042]     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise.  
         [0043]     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.