Boat propulsion apparatus
limited States tet [191 Wood  11 74,320 Apr. 1, 1975 BOAT PROPULSION APPARATUS [76] Inventor: Wilburn W. Wood, 2714 NE. 119th St., Vancouver, Wash. 98964 [22] Filed: Nov. 16, I973 [21] Appl. No: 416,635  
 [52] US. $1 115/28 R, 115/29, 416/81 [51] int. Cl B63h 1/36 [58] Field of Search 115/28 R, 29, 30, 28 A;  
 [56] References Cited UNITED STATES PATENTS 2.5701439 10/1951 O&#39;Bannon 115/29 FOREIGN PATENTS OR APPLICATIONS 59,786 8/1938 Norway 115/28 1.449.881 9/1967 France ..ll5/28 Primary Examiner-Trygve M. Blix Assistant Examiner-Gregory W. OConnor Attorney, Agent, or FirmEugene M. Eckelman [57] ABSTRACT A fish-shaped flexible body portion encloses a laterally flexible, vertically rigid support plate secured at its forward end to a vertical support from the boat. This vertical support has a drive shaft therein which projects therebelow and which has a pair of cam discs secured thereon in eccentric relation with extended or crank portions disposed 180 around the shaft from each other. Cam follower rings are rotatably supported on the cam discs, and pull members are secured at one of their ends to these rings and at their other ends to a rearward point on opposite sides of the flexible plate. A lateral spreader bar supported on a vertical shaft holds the pull members apart between their ends such that upon rotation of the motor shaft the leverage applied to the body member by the forward movement of the pull members causes a lateral undulating motion similar to the motion of a fish while swimming to provide a forward propelling drive.  
 2 Claims, 5 Drawing Figures BOAT PROPULSION APPARATUS This invention relates to new and useful improvements in boat propulsion apparatuses.  
  According to the present invention and forming an important objective thereof, there is provided boat propulsion means which utilizes an undulating motion similar to the swimming motion of fish to accomplish the forward propulsion, such means having the important advantages of providing good forward propulsion and at the same time providing a structure which can thread through or otherwise not hang up on underwater obstructions or cause harm to persons.  
  Another object of the present invention is to provide a boat propulsion apparatus of the type described which employs an outer flexible body member shaped somewhat like a fish and having a laterally flexible, vertically rigid longitudinal support plate arranged to be moved in an undulating motion by cam operated pull members driven alternately by a drive shaft from a boat motor.  
  Another object is to provide a boat propulsion apparatus of the type described which is readily steerable for efficient maneuvering of the boat.  
  The invention will be better understood and additional objects and advantages will become apparent from the following description taken in connection with the accompanying drawings.  
 In the Drawings:  
  FIG. I is a side elevational view of a boat in reduced size relative to the other views, the present propulsion apparatus being shown in installed position thereon;  
  FIG. 2 is a side elevational view of the present apparatus and a fragmentary portion of a boat, portions of the propulsion apparatus being broken away;  
  FIG. 3 is a longitudinal off-set sectional view taken on the line 3-3 of FIG. 2;  
  FIG. 4 is a fragmentary sectional view of cam operating means which forms a part of the drive means and which is shown apart from other structure; and  
  FIG. 5 is a fragmentary elevational view of the body support plate also shown apart from other structure.  
  Referring in particular to the drawings, the present device is designated generally by the numeral and is arranged to be mounted under a boat 12 at the stern, as viewed in FIGS. I and 2, or if desired at any other point along the bottom ofthe boat as determined by the position of the output shaft from the power plant in the boat. With particular reference to FIG. 2, the numeral 14 designates in dotted lines a conventional inboard motor which drives a vertical shaft 16 in a conventional manner. This shaft passes down through a tubular sup port 18 and is rotatably positioned therein by suitable bearings 20 at the upper and lower ends.  
  Tubular support 18 projects through an aperture 22 in the bottom of the boat and is supported in its depending relation by a flange 24 thereon which seats on a base 26 secured to the bottom of the boat. Tubular support 18 has rotation in the base 26 and has integral connection with steering means 28 of conventional construction such as a tiller which may be operated by hand or by steering cables or the like.  
  Secured integrally to the depending portion of support 18 under the boat is a horizontal support extension 30 in the form of an elongated, upright thin plate which has flexibility through its lateral or thin dimension but which is rigid through its height dimension so that it can be self sustaining horizontally when secured only at its front end to the support 18. The forward end of extension 30 takes the shape as shown in FIG. 5. It has an upper front edge portion 32 which is welded or otherwise secured to a rear surface: portion of support 18. Below the edge 32 is a rearwardly extending cut-out portion 34 which in the secured position of the plate 30 is disposed just below the bottom end of support 18. A notch portion 36 is provided in the top edge of a forwardly projecting tongue 38.  
  A bracket 40 has a bottom arm 42 welded or otherwise secured in the notch 36 and an upper arm 44 shortened relative to arm 42 and welded in a notched portion 46 in the front of tubular support 18 at the bottom thereof. Bracket 40 assists in securing the extension 30 to the tubular support 18 in its horizontal position.  
  Shaft 16 projects a short distance below the bottom of support 18 and has a pair of cam discs 50 and 52, FIG. 4, secured integrally thereon, these cam discs being circular in shape but being eccentrically secured on the shaft. These discs are arranged such that their extended or crank portions are in opposite directions, or at 180 from each other, and have annular cam followers 54 and 56 rotatable thereon, respectively, which in cross section are channel-shaped for support on the discs. .The cam discs are rotatable in the followers and said followers 54 and 56 are integral with rearwardly projecting pull members 58 and 60, respectively which are secured to a rearward point: on opposite sides of the extension 30. The rods 58 and 60 may comprise flexible rods, cables, etc. and are spread apart laterally intermediate their ends by a spreader bar 64 secured on an upright shaft 66. Spreader bar 64 preferably is of slightly flexible construction so that its arms can flex forwardly and rearwardly slightly for a reason to be described.  
  Supported on the extension 30 and on the lower portion of tubular support 18 in enclosing relation is a flexible, fish-shaped body member 68 which as best seen in FIG. 3 has a laterally thickened forward portion and a narrowing tapered portion toward the rear or tail. The tail 70 is flared outwardly similar to the tail of a fish. The forward edge 72 of the device has a top to bottom rearward taper with the upper end thereof lying up substantially close to the bottom of the boat whereby the front end will not hang up on obstructions as the boat moves through the water. Also, the front end 72 is pointed as viewed vertically to slide past such obstructions.  
  Body member 68 has aninternal cavity 74 to receive the support 18 as well as the lower shaft parts and the cam mechanism and the rearwardly extending rods 58 and 60, the plate-like extension 30 being molded in or otherwise enclosed in such body portion. The ends of shaft 66 are embedded rotatably in portions of the body member 68 on opposite top and bottom portions of cavity 74.  
  In the operation of the present device, the rotation of shaft 16 causes alternate linear forward drive of pull members 58 and 60. These pull members operating over the ends of spreader bar 64, causes a leverage drive laterally to the rearward portion of the body member 68 which undulates the latter similar to the swimming action of a fish to produce a forward propelling force. The two extreme positions of undulation are shown in full and phantom lines in FIG. 3 to illustrate the whipping condition of the body as it undulates back and forth. The spreader bar 64 being slightly springy will flex with the linear movement of the pull members 58 and 60 to prevent wear at the ends thereof. The shaft 64 can also pivot in its mounting in the body member 68 to relieve any strains which may be caused by forward and rearward movement of the pull members 58 and 60.  
  The present device thusprovides a propulsion means which has the efficient propelling force produced similar to that of the swimming action of a fish. It also has the inherent advantage of being movable through obstructions without hanging up. In addition, the device provides for good steering of the boat and will do no appreciable harm to persons who may come into contact with it while in operation.  
  It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention, or the scope of the subjoined claims.  
 Having thus described my invention, 1 claim:  
 1. Boat propulsion apparatus comprising a; a flexible body member having generally the shape of a fish with a thickened forward portion and a thinning rearward portion terminating in a tail,  
 b. tubular support means secured to said body member arranged to support the latter horizontally from its forward end under a boat,  
 c. a vertically rigid, laterally flexible member integrated at its forward end with said tubular support means and supporting said body member,  
 d. shaft means in said support means projecting into said body member and arranged to be driven by a boat motor,  
 e. a pair of horizontal cams on the projecting portion of said shaft,  
 f. said cams being eccentrically arranged on said shaft around from each other,  
 g. cam followers engageable with said cams,  
 h. and a pair of lever means connected at one of their ends to respective ones of said cam followers and at their other ends of said flexible member at a rearward point,  
 i. said levers upon rotation of said shaft being operated by said cams and cam followers to produce an undulating motion of the rearward portion of the body member laterally similar to the swimming action of a fish to provide a forward propelling force.  
 2. The boat propulsion apparatus of claim 1 wherein said lever means comprises a pair of pull members connected at one of their ends to respective ones of said cam followers and at their other ends to opposite sides of said flexible member at a rearward point, and lateral spreader means between said pull means between the ends of the latter.