Abstract:
A detachable planing enhancement system with two substantial planing surface areas attached symmetrically on the transom of an inflatable sportboat to provide a substantial lifting force thereon. The system includes a method of quick attachment and detachment to the transom of the inflatable sportboat and means to ventilate such planing surfaces with air to reduce drag at high planing speeds. The planing surfaces and attachment components are comprised of plastic compatible with the injection molding process of fabrication.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to the use of a planing enhancement system for inflatable sportboats. Planing enhancement systems such as trim tabs and drive unit lifting plates are known to improve the stability and planing performance and weight carrying capacity of motor boats. Such systems are permanently attached to the boat or drive unit of an outboard and can either affect the storage or out of the water transport of an inflatable sportboat or outboard motor. For this reason they are somewhat limited in size and lift potential. Most trim tab and lifting plates also retain their wetted surface area and wetted surface drag at high or maximum planing speeds. These system lose efficiency at high speeds when less wetted surface area is required for the desired amount of lift for planing. One example of a system that eliminates wetted surface area by totally unsubmerging it&#39;s surface area is found in U.S. Pat. No. 5,224,436. The planing surface or hull extension is placed at an appropriate distance above the hull bottom surface. A “step” effect is featured whereby the surface area is not in contact with the water once planing commences. 
     BRIEF SUMMARY OF THE INVENTION AND OBJECTS 
     It is the general object of the present invention to provide a planing enhancement system for an inflatable sportboat, to provide the advantages of similar existing systems and exceeding performance on an inflatable sportboat without the disadvantages and limitations. 
     It is a further object to the present invention to provide a planing enhancement system with a proportionally large planing surface area that provides substantially more lift or increased planing weight capacity than existing trim tabs or drive unit limiting plates for an inflatable sportboat. 
     It is a further object to present invention to provide a planing enhancement system that attaches and detaches from the transom of an inflatable sportboat while in the water and won&#39;t affect it&#39;s storage or that of the outboard motor. 
     It is a further object to the present invention to provide a planing enhancement system that is ventilated with air from the top leading edge to reduce it&#39;s wetted surface area and drag at high planing speeds. 
     These and other features and objects of the invention will become apparent from the following detailed description when taken with the accompanying drawings and claims, of which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective elevational view of a partial inflatable sportboat and transom utilizing the present invention; 
     FIG. 2 is a perspective elevational view of a planing unit; 
     FIG. 3 is a side view thereof; 
     FIG. 4 is a top view thereof; 
     FIG. 5 is an enlarged fragmentary perspective ele-vational view of a support strut and a structural member; 
     FIG. 6 is an enlarged fragmentary perspective ele-vational view of the top end of a support strut; 
     FIG. 7 is a bottom perspective view of a partial inflatable sportboat hull bottom and side tube and transom with attachment of mounting brackets; 
     FIG. 8 is a perspective elevational view of a partial planing unit and transom with bottom mounting bracket; 
     FIG. 9 is an enlarged fragmentary perspective ele-vational view of the top end of a support strut and a top mounting bracket; 
     FIG. 10 is a top view of a partial side tube and transom with mounting brackets and attached planing unit; 
     FIG. 11 is rear view thereof; 
     FIG. 12 is a sectional view taken substantially along line  12 — 12  in FIG. 11 of a planing unit and a transom and a hull bottom; 
     Corresponding reference numerals designate corres-ponding parts throughout the several views of the drawings. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to FIGS. 1 through 12, a maritime planing enhancement system  40  is provided for an inflatable sportboat  20  having a transom  22 , a starboard and port side tube  24  and a hull bottom  26 . A planing unit  42  which attaches and detaches to mounting brackets  70  which are permanently attached to the transom  22  of the inflatable sportboat  20 . Both the planing unit  42  and mounting brackets  70  are comprised of plastic compatible with the injection molding process of fabrication. The planing unit  42  and mounting brackets  70  are attached and positioned on each side of the transom  22 . The planing unit  42  on the starboard side is symmetrical with the planing unit  42  on the port side and they are evenly spaced between a drive unit  32  of an outboard motor  30 . The attachment of the planing unit  42  is horizontally pivotal on a bottom mounting bracket  72  and a top mounting bracket  82  and also vertically pivotal on the bottom mounting bracket  72 . The vertical angle of attack or trim of the planing unit  42  is selected using the top mounting bracket  82 . The planing unit  42  is comprised of a planing plane  43  shaped to give the maximum lift by filling most of the area between the side tube  24  and drive unit  32 , with enough space aft of the drive unit  32  to rotate the outboard motor  30  when turning. The aft end of the planing plate  43  extends out away from the transom  22  to an extent which doesn&#39;t adversely affect the turning capability of the inflatable sportboat  20 , and is curved to reduce lateral drag while turning. 
     The planing unit  42  as shown in FIGS. 1 through 6 is comprised of the planing plate  43  which is smooth and flat on the bottom side for reduced drag in the water. The top side of the planing plate  43  is reinforced with a structural member  44  which also distributes the upward force to the lower bracket  72  and the support strut  62 . A hook notch  46  on the end of the structural member  44  locks into the lower mounting bracket  72  and a strap  48  is used to release the lock. The top end of the support strut attaches to the top mounting bracket  82 . A planing plate extension  56  is attached by rivets  58  to the planing plate  43  and fills in the area in front of the drive unit  32  to reduce water spray. The planing plate  43  has a contact area  54  which is rounded to butt up against the side tube  24  with minimal wear. The support strut  62  is made of anodized aluminum and connects to the structural member  44  to transfer force from the planing plate  43  to the top mounting bracket  82 . The support strut  62  has a bend at the bottom end and the top end in opposite directions to counter the bending stresses on the support strut  62  itself. As shown in FIG. 5 the bottom end of the support strut  62  can rotate and is permanently attached to the structural member  44  through a hole  45  and secured with a screw  63  that screws into a hole  67 . The top end of the support strut  62  as shown in FIG. 6 has a locking mechanism which locks into the top mounting bracket  82  and is comprised of a pressure collapsible washer  64  made of nylon and a screw  66  which screws into a hole  65 . 
     The mounting brackets  70  as shown in FIG. 7 are permanently attached to the transom  22  of the inflatable sportboat  29  with screws  86  which go through holes  85  and into holes  88  and screws  78  which go through holes  87  and into holes  91 . Bolts (not shown) are used with a transom  22  that is made of a thin, hard material such as aluminum. A template (not shown) is used to position and drill each of the holes  88 ,  91  into the transom  22  at the proper location. All mounting brackets  70  are installed using a marine grade sealant to prevent water intrusion into the transom  22 . 
     As shown in FIG. 8, the mounting brackets  70  will quickly accept the planing unit  42  for attachment, with the bottom mounting bracket  72  which has a latch slot  74  in the middle where the structural member  44  inserts. The structural member  44  has a gap  47  which allows a hook notch  46  to be ben away from the planing plate  43  with a latch strap  48  to clear the latch bar  76  in the bottom mounting bracket  72  while insertion. When the latch strap  48  is released, the hook notch  46  locks down over the latch bar  76  and locks the structural member  44  in place. 
     The top mounting bracket  82  as shown in FIG. 9 has several selection holes  84  so different trim angles can be selected for the planing unit  43  using different holes for attachment. The mounting bracket hole  84  tapers to a smaller inside diameter at the center. When the end of the support strut  62  is inserted through the bracket hole  84  the collapsible washer  64  collapses while passing through the mounting bracket hole  84  and expands on the other side to hold the support strut  62  in place, and the planing unit  42  is completely attached. To detach the planing unit  42  the same procedure is followed in reverse and the planing unit  42  can be attached or detached with the inflatable sportboat  20  in the water  10 . 
     As show in FIGS. 10 and 11, besides the simplicity of a single bottom mounting bracket  72 , the mount brackets  70  run nearly vertical and the planing unit  43  can hinge laterally parallel to the hull bottom  26 ; this movement gives the drive unit additional turning room when needed (FIG.  10 ). Also, unlike solid full length bottom hinges on most trim tabs, a single bottom mounting bracket  72  allows the full ventilation of air under the planing plate  43  as shown in FIG. 12. A ventilation gap  28  between the transom  22  and the planing plate  43  allows air to be sucked down (Venturi effect) and under the front end of the planing plate  43 . The air mixes with the water  10  and creates air pockets and bubbles  90  which travel along with the water  10  which reduces direct contact of the planing plate  43  with the water  10  for less drag. A single bottom mounting bracket  72  is possible only because the planing plate  43  contact area  54  rests against the side tube  24  to support upward pressure as show FIG.  11 . FIG. 11 also shows the overlap of each of the plate extensions  56  to accommodate different sized transoms  22 . 
     Other embodiments of the invention have a plastic support strut  62  (not shown) which is hollow from the bottom and has an internal grid for strength. Also, a structural member  44  with several strength members which from a grid across the top surface of the planing plate  43  (not shown). This design is light in weight and every component is compatible with the injection molding process of fabrication.