referring to the accompanying drawings there is illustrated a de - rooting apparatus 10 that mounts upon a harvester vessel 12 as illustrated in fig4 . the de - rooting apparatus includes a jib 14 with two parallel jib arms 16 joined by cross members 18 . a lug 20 is mounted on the in - board or free end of each arm 16 . on the underside of each arm is a plate 22 that is pinned to the clevis on the piston rod of a cylinder 24 . the two cylinders 24 are lift cylinders for the jib and for the de - rooting apparatus as a whole . at the outboard of the jib is a hanger 26 . this includes two angle braces 28 converging downwardly from opposite sides of the jib at its free end . a center brace 30 slopes downwardly to below the end of the jib from the center cross - member 18 . these three braces 28 and 30 support a vertical sleeve 32 . sliding in the sleeve is a square tube 34 . a series of holes 36 in the tube and two pins 38 through the sleeve 32 pin the tube adjustably to the sleeve so that the overall length of the hanger 26 can be adjusted . at the bottom end of the tube 34 is a universal joint 40 . this includes two side plates 42 , connected to a yoke 44 by a lateral pin 46 to provide a lateral pitch axis 48 . a longitudinal pin 50 connects the yoke between two laterally extending plates 52 mounted on a base plate 54 . the longitudinal pin 50 has a fore - and - aft oriented roll axis 56 . a lug 58 is mounted on the tube 34 above the yoke 46 and a second lug 60 is mounted on a forward extension of pin 50 , below the lug 58 . these two lugs are linked by a pitch control means in the form of an hydraulic cylinder 62 that may be extended and contracted to control pitch movements about the lateral pitch axis 48 . carried on the base plate 54 are two rotors assemblies 64 . they are arranged side - by - side but converging slightly in the normal direction of travel . each rotor assembly includes a rotor frame 66 with a lateral head 68 and two depending side plates 70 . extending between the side plates is a rotor 72 including a rotor drum 74 and a series of rigid teeth 76 spaced uniformly over the drum surface to radiate from the drum surface . the drive means for the rotor is an hydraulic motor 78 connected to the outer end of the rotor drum at the outer end of the rotor frame 66 . the two motors are independently controllable and reversible . as illustrated most particularly in fig1 the two rotors of the two rotor assemblies have respective rotor axes 80 and 82 that intersect at an obtuse angle . the teeth 76 are flat plates uniformly distributed over the drum surface so that with the convergent drums , the plates will sweep substantially the complete surface being traversed as the rotors are advanced across the surface and simultaneously rotated . fig4 illustrates a vessel carrying the harvester . the vessel includes a superstructure 84 including an operator station with seating and the appropriate controls . the vessel may have mounted on it a harvester head 86 that extends into the water and serves to cut vegetation and to pick up floating vegetation from the surface of the water for delivery to a conveyor - bottom container 88 mounted amidships in the vessel . the vessel also includes an unloading conveyor 90 extending from the container to the rear of the vessel for off - loading the contents of the container . when the harvester head 86 is mounted on the vessel , the de - rooting apparatus 10 is dismounted and its hydraulic controls disconnected for connection to the harvester head . the hydraulic controls for the system are illustrated most particularly in fig6 . as illustrated , the system includes a motor 92 driving an hydraulic pump 94 . a set of controls 96 controls flow to the jib cylinders 24 through a line 98 . hydraulic lines 100 and 102 lead from the controls to the two hydraulic motors 78 for the rotors . lines 104 deliver hydraulic fluid to the pitch cylinder 62 . all of the hydraulic lines are equipped with quick release fittings 106 to enable the de - rooting head to be quickly disconnected when desired . the jib 14 is connected to the vessel by two pins 108 , aligned on a lateral jib axis 109 ( fig1 ) while the lift cylinders 24 are connected to the vessel by respective pins 110 . a similar quick disconnect mechanism is used for the harvester head 86 so that the harvester head and the de - rooter apparatus may be connected to the vessel alternatively . in use of the apparatus , the hanger length is adjusted to accommodate the water depth encountered . the jib lift cylinders act as jib control means to provide further adjustment that may be required during operation . when the de - rooter is lowered to the surface of the hydrosoil and the rotor is actuated , the teeth on the rotors sweep through the soil , loosening the soil and uprooting plants that are present . as the vessel advances , the rotors remain generally parallel to the adjacent hydrosoil surface due to the action of the rotor leveling means , including the roll axis pin 50 and the pitch axis pin 46 with pitch control cylinder 62 . in use , the rotor may encounter underwater obstacles . the free pivoting movement about the roll axis will allow the rotors to clear most such obstacles automatically . this also allows the rotor to follow the lateral contours of the hydrosoil . the pitch movements are controlled by the operator to match , insofar as possible , the contour of the hydrosoil in the direction of travel . where any area has been treated and there is quantity of floating vegetation to be collected , the de - rooter apparatus may be dismounted from the vessel and replaced with the harvester , including the pickup conveyor , for collection of this material . the exchange is quite simple , involving the release and reconnection of a set of pins and a set of quick release hydraulic couplings . while one embodiment of the present invention has been described in the foregoing , it is to be understood that other embodiments are possible within the scope of the invention . for example , the angle of convergence of the two rotors may vary widely , for example , between 120 ° and 180 ° ( aligned rotors ). the converging rotors arrangement is preferred because it provides improved tracking and allows each tooth to treat a wider swath of vegetation . the present invention in its various aspects is to be considered limited solely by the scope of the appended claims .
an aquatic plant de - rooting apparatus includes a jib and a vertically adjustable hanger to be mounted on a vessel . the hanger carries two forwardly convergent rotors , each with a series of flat blades projecting radially from it . the rotors are independently driven by hydraulic motors . the rotors act to uproot the aquatic vegetation to remove the vegetation and inhibits its future growth .