Abstract:
A self-propelled underwater transport vehicle provides propulsion for one or more divers to allow submerged travel over extended distances. The vehicle has a cylindrical open hull supporting a deck upon which a diver is supported in a prone position. A blunt bow extends upwardly from the front of the hull, and develops a flow shadow in which the diver is positioned. A control yoke, operable by the diver, is connected to steering elements, which may include bow planes and a pivoting thruster. The cylindrical hull allows the vehicle to closely approach objects without contact therewith, while the flow shadow developed by the bow minimizes drag, despite the open structure of the vehicle.

Description:
The present invention relates to a submersible, self-propelled transport device for scuba divers and the like. Priority of Provisional application 60/195,384 of Apr. 7, 2000 is claimed. 
    
    
     BACKGROUND OF THE INVENTION 
     Military, commercial and recreational pursuits all may require that undersea personnel travel substantial distances under water. Military operations require that military personnel approach an objective from the sea and reach the objective quickly, quietly and in good physical condition. Commercial endeavors often require the shuttling of personnel to and from an undersea work site, while recreational pursuits, such as wreck exploration, may require substantial travel from the surface to and from the exploration site. As swimmers equipped with self-contained underwater breathing (SCUBA) apparatus have a limited underwater duration, manual propulsion at a slow travel rate both depletes the available air supply, limiting the time that the diver can spend at his assigned duties, and also limits the range of travel. In addition, the physical exertion required for manual propulsion can leave the diver fatigued, low on air, and incapable of performing at an optimum level. 
     There have heretofore been developed propulsion devices which purport to assist in the transport of divers. For example, U.S. Pat. No. Re 36,093 to the present inventor and another discloses a submersible boat capable of both surface and submerged travel in which divers are situated in the interior. Such a construction is typically capable of delivering a plurality of personnel to a target location, but is not intended for use by one or two divers. Further, the device is relatively large and does not have the maneuverability of a small, individual use transport vehicle. 
     U.S. Pat. No. 5,379,714 to Lewis et al. discloses an aquatic vehicle for the underwater transport of swimmers and divers in which the user holds attachment grips located on opposed sides of the body. 
     In U.S. Pat. No. 5,988,096 of Nov. 23, 1999 to Benesch et al. a diver tow vehicle is provided, wherein the diver is behind a bullet-shaped shell. The device is not independently powered, however, but rather is towed by another vehicle. When the tow vehicle is disconnected from the propulsion vehicle, the tow vehicle stops and rises to the surface. 
     BRIEF DESCRIPTION OF THE INVENTION 
     It is a purpose of the present invention to provide a personal swimmer transport device to enable a diver to travel at increased speeds underwater over longer distances than has previously been possible with diver propulsion units. 
     A further purpose of the present invention is to provide a swimmer transport device which is capable of transporting cargo in addition to a diver. 
     A further purpose of the present invention is to provide a highly maneuverable, independently powered swimmer transport device. 
     Yet a further purpose of the present invention is to provide a swimmer transport device which is of compact design, and may be collapsible for storage. 
     In accordance with the foregoing and other objects and purposes, a swimmer transport device constructed in accordance with the present invention comprises a self-powered, open deck underwater travel watercraft providing motive power for supporting a diver oriented in a prone position above or upon the deck. The vehicle has a generally cylindrical open hull supporting the deck and having a blunt bow. The blunt bow forms a shroud extending above the deck whereby the diver, extending in a generally prone position on the craft deck, which is tethered to the watercraft within the flow shadow of the bow. A cargo area can be located below the forward deck portion. Propulsion, steering and depth control apparatus are provided, along with associated swimmer-operated controls therefor. A viewing port is provided in the bow to allow the swimmer to view the area ahead of the vehicle for navigation and reconnaissance purposes. Direction and depth gauges may also be provided. 
     Preferably, the buoyancy of the watercraft is trimmed to establish neutral buoyancy, thus facilitating control and operation of the device by the diver, and improving its maneuverability and travel efficiency. Depth control may be accomplished by a pair of bow planes coupled to a control yoke, while port/starboard steering may be accomplished by a rear pivoting electrical thruster, also controlled by the control yoke. The transport device may be constructed in forward and aft portions which are capable of being disconnected and slid together to allow the transport device to be stored in a collapsed configuration. The bow planes may be removable to allow the watercraft to be passed through hatches on conventional watercraft, such as submarines. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A fuller understanding of the present invention will be accomplished upon review of the following detailed description of a preferred, but nonetheless illustrative embodiment thereof, when reviewed in connection with the annexed drawings, wherein: 
     FIG. 1 is a side elevation view of a swimmer transport device constructed in accordance with the present invention; 
     FIG. 2 is a rear elevation view thereof; 
     FIG. 3 is a front elevation view thereof; 
     FIG. 4 is a sectional view taken along line  4 — 4  of FIG. 3; and 
     FIG. 5 is a top view taken along line  5 — 5  of FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With initial reference to FIG. 1, the self-propelled swimmer transport device (“STD”)  10  constructed in accordance with the present invention is adapted to transport a diver  12  lying in a prone position within the vehicle, the diver controlling the STD through operation of a control yoke and thruster control. Diver transport is preferably enabled by a T bar  56  connected to the forward portion of the hull by an adjustable length rope or lanyard. The T bar is held by the diver between and behind the legs allowing the forward motion of the vehicle to be coupled to the diver. The vehicle  10  is of an overall length of approximately seven feet, providing adequate support for a wide range of diver physiques. A second diver, lying atop and behind the first diver, can also be accommodated through the use of further transport enabling means, such as lateral handgrips located along the vehicle sides, in conjunction with a second T bar, which is held by the second diver&#39;s legs. 
     The vehicle includes a blunt bow  14 , shaped to minimize underwater drag, the upper part of the bow projecting above the top of the side walls of the generally cylindrical hull  16 . The curved or rounded bottom of the hull, as seen in FIGS. 2 and 3, permits the STD to closely approach the seabed or objects below the vehicle without colliding therewith, as Bernoulli attraction is minimized by the absence of a substantially flat bottom hull surface. The aft portion of the hull tapers upwardly, a skeg  18  extending downwardly from the tapered portion of the hull. A thruster  20 , mounted upon a vertical pylon  22  extending through the hull behind the skeg  18 , comprises an electrical motor drive  24 , coupled to propeller  26 . The pylon  22  is journaled in the hull, allowing the thruster  20  is rotatable about the vertical axis of the pylon for port/starboard steering purposes. A circular shroud  78  protects the diver from the propeller and also serves as a lateral stabilizer, preventing yaw of the vehicle. The tapered aft hull portion minimizes the drag of water flowing past the hull, and streamlines the flow past the thruster, improving thruster efficiency. 
     A transparent viewing port  28  is located in the bow, providing forward visibility for the diver, allowing the diver to remain fully prone and substantially within the flow shadow of the bow at all times during travel. A pair of bow planes  30 , operable by the diver, allows for ascent and descent of the vehicle. 
     With particular reference FIG. 4, a main deck  32 , located between the opposed hull sidewalls and supported at its forward end by bulkhead  36 , is provided within the hull  16  and provides a protected storage volume  80  within the hull. While the diver is of typically buoyantly neutral and thus does not need the deck for support, the deck can also assist in supporting a negative buoyancy diver in the prone position behind the bow. Preferably, a main portion of the deck is located in the aft portion of the vehicle, and is aligned and positioned such that the waist and legs of the diver can be supported thereby, while providing mobility to the diver&#39;s upper torso to allow the diver to grasp the control yoke  54  and operate other controls and devices as may be required. With the diver in the prone position, the upwardly extending bow  14  provides a shroud or shield function for the diver, diverting the water flow substantially around the diver and thus contributing to the creation of a low drag coefficient for the vehicle. 
     The main deck may be constructed of an appropriate rigid closed cell foam to allow the vehicle to attain neutral buoyancy. The foam is provided with an appropriate polymer coating or the like to afford rigidity and toughness to the deck. A fabric forward deck portion  44  may extend forward from the main deck  32 , and forms a top for a storage compartment volume  34 . The compartment  80  below the main deck  32  provides a protected mounting location for sealed battery pack  38 , which provides electrical power for the thruster  20  and other electronic gear which may be provided. Appropriate cables, such as  40 , interconnect the battery pack and the equipment to which it is connected. The fabric deck  44  may be removably affixed at its forward end to bulkhead  42 , the fabric deck being released from the bulkhead to provide access to the compartment volume  34 . The fabric deck  44  may also provide a measure of additional support for the diver. 
     A control assembly  46  is positioned at the bow, and is operable by the diver when in the prone position. The control assembly may include a first, transverse control arm  48 , extending across the hull and journaled in the hull side walls, and which bears the bow planes  50 . A second control arm  52  may be mounted to the first arm  48 , extending in a generally perpendicular fashion therefrom, the end of the arm  52  bearing the control yoke  54  which is held by the diver and which is capable of a pivoting, lateral steering, motion. A control cable  58  extends from the control yoke  54  to a push arm  60  mounted to the upper end of motor drive pylon  22  within the hull, whereby port and starboard steering/pivoting action of the control yoke causes an appropriate pivoting action of the motor drive  24 , effecting port /starboard steering. In a similar manner, a fore and aft pivoting motion of the control yoke  54  causes rotation of first control arm  48  about its longitudinal axis, effecting operation of the bow planes  50 , and providing for ascent and descent control of the vehicle. The control yoke  54  thus provides full directional control. 
     Also mounted at the bow of the vehicle is an instrument module  64  which is preferably located at the bottom of the bow such that it can be observed by the diver without raising his head. The module may include a compass  66  and depth gauge  68 . It may also include a switch  70  for the thruster  20 . The switch  70  may be of the simple “on/off” variety, or may include proportional control circuitry to allow varying of the speed of the thruster motor as well as for a reverse function as may be appropriate. 
     Because the STD has significant military uses, it is advantageous that it be of a construction which permits it to be easily deployed from military vessels, such as submarines. Accordingly, the vehicle may be constructed in fore and aft sections, as shown in the Figures. In particular, the aft portion  72 , which may include the tapering portion of the hull and terminates just forward of the bulkhead  36 , is of a slightly smaller diameter than that of the forward portion  74 . The forward and aft portions may be locked together in the extended and assembled position by the use of a series of locking pins or the like. The connection between the forward and aft sections may be intentionally formed with a gap or spacing between portions of the adjacent sections to allow for rapid drainage of the hull when the vehicle is lifted from the water. With the pins removed, the aft portion  72  can be slid forward within the hollow forward hull portion, substantially collapsing the length of the vehicle. The aft portion may be slid forward until the forward end of the hull portion is in contact with the forward bulkhead  42 . The fabric deck may be folded back for clearance purposes. 
     The hull may be preferably constructed from welded marine grade aluminum, the viewing port  28  being constructed of an appropriate plastic. With an overall deployed length of approximately 84 inches, and a hull diameter of 24 inches, the STD can be deployed through standard military submarine hatches. When collapsed, the overall length is approximately 50 inches, providing a compact unit. The batteries of battery pack  38  are preferably of a silver-zinc composition, providing high output. To establish and trim the buoyancy of the vehicle to neutral, foam elements  82  may be installed on the inside hull sides as required. Approximately 3 cubic feet of volume in the forward storage space  34  is provided. 
     The present invention&#39;s structure of a neutral buoyancy watercraft with a cylindrical hull having a bow shroud for a prone diver, coupled with a rear thruster shroud and tapered aft hull section, yields a swimmer transport device having substantially less drag and improved stability, allowing the vehicle to maintain depths and tracking with minimal deviation and with minimal effort required to control the watercraft.