Abstract: Boat stand assemblies for dry dock maintenance or storage of boats with and without keels including two or more rigid frames of adjustable width each including a pair of struts of adjustable height, the frames being connectable by cross braces to provide a complete stand and further including a keel stand assembly similarly constructed of height and spacing adjustable struts.

Abstract: In a boat hoist having a platform for raising and lowering a boat by a normally manually rotated circular lift wheel, winch, and cable arrangement, an electrically powered drive motor assembly mounted adjacent the lift wheel and including a drive wheel biased between a position of non-engagement with the lift wheel, and a position of engagement therewith for rotation of the lift wheel, power for the drive motor provided by the DC power source within the boat being moved or by a shore supplied AC power source.

Abstract: A portable watercraft lift including a pair of transverse, laterally spaced apart, arch shaped support members which are each detachably connected at the top thereof to one end of an elongated connector beam member. An electrically powered winch, having a winch drum, is detachably mounted on the elongated connector beam member at a point equidistant between the arch shaped support members. Each of the transverse arch shaped support members is provided with lifting cord means and associated pulley means, and one end of each of said cord means is operatively attached to the winch drum. Each of the lifting cord means and associated pulley means are connectable as a combination to a watercraft support member for supporting a watercraft by either a lifting ring, a cradle or lifting straps. When the power winch is operated the cords attached to the drum of the power winches are pulled in from both directions simultaneously creating a lift on a watercraft.

Abstract: The piston rod of a lift cylinder unit on a boat lift is selectively locked from extending or retracting by a locking mechanism having a clamping ring which is sleeved on the piston rod and is biased into locking position by a compression spring engaging a piston in a locking cylinder. This cylinder is selectively supplied with pressurized water to compress the spring and thereby release the clamping ring. Hydraulic lines extend to the lift cylinder and locking cylinder from a control manifold located adjacent the boat lift for remotely operating the lift and the locking mechanism.

Abstract: A sailboat davit connectable into the ground adjacent a seawall, water's edge or other like supportive objects for lifting and lowering a small sailboat. The device includes an elongated upright support member having a radially outwardly extending boom connected at one end to the upper end of the upright support member. A generally horizontal spreader beam is connected at a mid-point thereof to the distal end of the boom so that the spreader beam extends in either direction preferably from a plane generally defined by the upright support member and the boom. A flexible cable and pulley arrangement, winch-activated, is provided having a flexible cable downwardly extending over a pulley at each end of the spreader beam, each end of each cable being connectable to the sailboat hull whereupon the sailboat is lifted and lowered in response to winch activation.

Abstract: A load lifting device for small watercraft has a vertical post having a lower post portion extending downwardly in the water from the top of the dock and rigidly mounted thereto and having an upwardly extending rectilinear extension and a vertically moveable cradle cantilevered off the post with a winch at the top of the extension connected to the cradle for raising and lowering it; the upwardly extending extension of the post being mounted on the lower post portion for rotation relative thereto so that when the cradle is moved vertically to a position carried by the extension it may revolve with such extension to swing a watercraft carried by the cradle over the dock or the water as desired. A lock is provided for preventing the post and extension from rotating during transition of the cradle between the two.

Abstract: A boat lift that is collapsible into a plurality of segments for quick and convenient transportation and storage during the off-season. The boat lift comprises a frame and a boat-engaging carriage that is movable on the frame between an elevated position and a lowered position. The frame forms an inclined track upon which the carriage traverses and comprises two spaced siderails, and a front and rear brace member. The front brace member comprises two segments that are each pivotally attached to a respective siderail. The segments are selectively removable from one another to permit the segments to be folded back adjacent their respective siderails. The rear brace member is selectively removable from the siderails so that the frame member may be collapsed into three separate segments. The carriage is removable from the frame and may be collapsed in a similar manner.

Abstract: This invention relates to a combination wheeled boat duck and lift which is portable for easy, convenient, and safe movement to and use in almost any location about a body of water. The boat dock and lift comprises a pair of wing decks hingedly attached to a forward main deck. The wing decks can be folded upon the hinged joints for easy transportation of the boat dock and lift and are vertically adjustable with jackscrew means to provide a level surface relative to the main deck for a user to safely walk thereupon. The wing decks and main deck cooperatively define a boat receiving space therebetween with a lift frame base adjustably mounted in the boat receiving space. A winch mechanism is used to raise and lower the lift frame base relative to the wing decks and the main deck. This boat dock and lift provides the user with convenient and safe access to his/her boat from any side thereof.

Abstract: A boat lift is arranged to include spaced rectilinear frameworks having leg members splayed exteriorly of a first framework extending to the second framework. The legs may optionally include telescoping extensions, with the extensions and legs having foot plates for mounting the frameworks to a support surface. Flexible webs are mounted at opposed ends between the frameworks to position and lift a boat therebetween.

Abstract: A portable dock is shown having a deck with a portion providing a support platform for a boat lift. A boat lift is pivotally connected to the platform so that the boat lift can be pivoted from a position adjacent the dock to an inverted position on and supported by the platform. A hoist guide is mounted above the deck and connected to the boat lift so that the boat lift can be lifted up, pivoted over center and released to rest in an inverted position on the support platform.

Abstract: A windsurfing ramp which is flexible so as to provide a spring action and optimize the translation of windsurfing craft velocity into launch trajectory. The windsurfing ramp is compact by design, easily transported and easily assembled and installed. The windsurfing ramp is safe and eliminates the possibility of a windsurf craft rudder catching on a portion of the ramp thus injuring a sailor or damaging the windsurf craft. The ramp is made up of a plurality of substantially parallel, spaced apart tubular members which are flexible under the weight of a windsurf craft and sailor. The support members are arranged in a planar configuration such that one side edge is submerged when disposed on a body of water while an opposite side edge is elevated in the water.

Abstract: The invention concerns a boat hull support that includes a pair of hull support members spaced from each other and each pivotally mounted intermediate its ends to spaced uprights. A guide post is mounted for vertical movement in the space between the support members, and sliding rods join the support members to the guide post so that vertical movement of the guide post will be translated into substantially equal movement of the support members about their pivots.

Abstract: A launching and lift assembly for small watercraft such as a jet ski comprises a skid cradle for seating the watercraft thereon for sliding movement off an end thereof. The skid cradle is mounted on a dock for rolling movement thereon forwardly over a launching edge thereof on a rear caster and on a pair of forward support rollers secured to the dock at its launching edge, for downward tilting of the skid cradle on the support rollers over the launching edge to cause the watercraft to slide downwardly off the tilted skid cradle and into the water when the skid cradle and seated watercraft are rolled forwardly on the dock to a position wherein their center of gravity is located forwardly of the support rollers.

Abstract: Upwardly extending pivoting booms are supported on a rectangular base which is submerged in water. Watercraft supports on mounting arms are connected to the pivoting booms. A double-acting hydraulic cylinder attached between the rectangular base and pivoting booms swings the pivoting booms upwardly until they are braced by boom supports on the rectangular base at an angle over center. This raising of the pivoting booms lifts the mounting arms and watercraft supports to remove a craft from the water and disposes the booms, mounting arms, and craft in a stable, secure over center configuration. Actuation of the double-acting hydraulic cylinder in the opposite direction forces the booms back out of the over center position and lowers the craft into the water.

Abstract: A method of assessing a ships weight so as to e.g. assist in its design and development, or to ascertain its actual center of gravity or its loaded state, comprises positioning the ship on a dry dock platform made up of a number of articulatedly joined sub platforms connected for lifting and lowering by hoist winches. The hoist winches include signal devices which signal the load each is supporting, to a computer and visual display unit which displays the loads. The computer computes e.g. the center of gravity or the ships weight, in the displacement of the center of gravity from its designed position, the information then being passed to the designer.

Abstract: A ground supported boat lift including a frame which is pivotally movable about two shorter spaced apart parallel legs connected at each rear corner of the frame from an upright position to a generally horizontal position of the frame. A boat cradle is connected and extends perpendicular between the legs and is raised from being in close proximity to the ground to being above the ground by the legs as the frame is pivoted into a horizontal position. Optional removable wheels and a trailer tongue convert the device to a more conventional boat trailer.

Abstract: A clamp mechanism for an adjustable torsion bar of a boat lift. The torsion bar includes square tubes which fit together telescopically to allow the torsion bar length to be adjusted. Each clamp mechanism includes a pair of opposing angle members lined on the inside faces of their flanges with plates which extend along a part of the length of each flange. The angle members are applied in opposition to one another with the inside faces of the flanges directly against the larger tube and the plates against the smaller tube. The angle members are clamped to the tubes by nuts and bolts applied to lugs which project from the angle members.

Abstract: A boat lift in which a hydraulic pump and cylinder with a piston is mounted on a manual boat lift so that the piston rod carries a pulley which engages the lifting cable so that when the piston moves in the cylinder the boat will move up or down.

Abstract: Method for launching and retrieving a boat by attaching a hook on a constant tension line connected to a reel. The reel includes a length of retractable line which is reeled out to a predetermined point, and a button on the reel housing engages the reel to set the length of line on the reel.

Abstract: The Boat Lift has two support rods with a lower pulley connected to each end of each support rod. An upper pulley and a winding device with a ratchet are located above each lower pulley. Four cords and a winch are provided. Each cord has one end connected to one winding device and extends downward around its associated lower pulley; upward around its upper pulley; and has its other end coupled to the winch. Operations of the winch lowers and raises the support rods. The ratchets and winding devices are employed to allow the two support rods to be leveled.

Abstract: A pair of opposed protectors for protecting the hull of a boat from abrasion or other contact damage by a sling used in lifting the boat during launching, haul out or the like, each protector being in the form of an elongate member which is positioned between the boat hull and the portion of the sling which would otherwise engage the hull, each protector being affixed at one end thereof to the boat by reverse U-shaped members which releasably engage the lifeline of the boat to permit the position of the protector to be adjusted longitudinally of the boat for alignment with the sling, each protector having a polyvinyl chloride hull contacting face with a layer of cellular polyvinyl chloride or cellular polyethylene backing material bonded thereto, a two sided pressure sensitive tape being affixed to each protector adjacent the opposed end thereof for further releasably affixing each protector to the boat.

Abstract: An adjustable davit arrangement is attachable to a pair of pier pilings for raising or lowering a vessel and comprises a first davit mounted on a first pier piling, a second davit mounted on a second pier piling, a rotatable drive pipe extending between respective distal ends of the first and second davits, pick-up flanges disposed near respective ends of the rotatable drive pipe for raising or lowering the vessel via respective cables as the drive pipe is rotated, and a winch motor mounted in proximity to one of the davits and operating with a gear reducing drive drum mounted on the drive pipe so as to cause the drive pipe to rotate, thereby raising or lowering the vessel. Simplicity in assembly and operation, and economy, are achieved by use of a single winch motor.

Abstract: A lift for water vehicles comprising a pair of vertical pipes or tracks attached adjacent their upper ends to one side only of a dock sructure which is positioned alongside a body of water, a tank assembly having a roller assembly thereon for engaging the sides of the pipes for rolling upwardly and downwardly thereon, the tank assembly having a tank mounted thereon and an upper opening for introducing air into the tank to displace water therefrom through a lower opening at the bottom of the tank so as to cause the tank to rise, the tank assembly having a pair of spaced padded blocks for supporting a water vehicle thereon, the roller assembly having rollers thereon adapted to rise along the inboard sides of the pipes when the tank assembly moves vertically in response the introduction of air to and removal of air from the tank, whereby, when a water vehicle is supported on the padded blocks and the tank assembly is in its lowermost position, air can be introduced into the tank while water is forced outwardly f

Abstract: A lock using lock chambers and lock gates capable of reducing the water consumption in the operations of raising or lowering the boat passing through the lock from one level to another. The lock includes flexible air chambers capable of being inflated with air, located on bases of the lock chambers which are connected by a pipe equipped with a valve for controlling a flow of air between the air chambers.

Abstract: A boat lift and leveler are provided in which the boat lift consists of a cradle supported by at least two pontoons laterally disposed beneath and fixed to the cradle. A leveler for the lift includes a pair of pneumatic duct systems. One of the systems connects to air vents on the starboard side pontoons and the other system connects to air vents on the port side pontoons. Each system includes an intake path, an exhaust path and a valve in each path. The intake path is connected to a source of air under pressure and the exhaust path extends to the atmosphere. An enclosure fixed to the lift lists to starboard or port with the lift. A V-shaped track rests in the enclosure. The track has a starboard arm which rotates below horizontal at a predetermined degree of starboard list of the enclosure and a port arm which rotates below horizontal at a predetermined degree of port list of the enclosure.

Abstract: A lift apparatus has a load member, a lift cradle and a lifting arrangement. The load member has a rail or track portion which provides a path when raising and lowering the lift cradle. The load member also has a mounting portion for mounting the load member to an adjacent structure such as a dock, a pier or a wall. The mounting portion has a web, which stands off mounting hardware, such as a mounting plate, from the rail portion. The lift cradle has bearings for sliding along the rail portion. The bearings have a gap, which allow the bearings to slide along the rail portion without interference from the web. When the bearings are free of the web, the lift cradle can rotate, to deposit the load onto a dock. The lifting arrangement is rotatively coupled to the upper end of the load member, so as to rotate with the lift cradle.

Abstract: A system for launching a boat includes a platform which is movable horizontally over the edge of a seawall, a dock or the like. Once the platform has been moved over the edge of the seawall, it then may be lowered vertically under the surface of the water. Once under the surface of the water, the boat may be floated away from its support on the platform.

Abstract: Hoisting of boats is made faster and performable by a single operator by utilizing an hoisting apparatus which can be used with any lifting crane available and which comprises a balance having at least a longitudinal beam and two tubular crossbeams, out of the extremities of which extend, respectively, horizontal arms telescopically extensible and retractable driven by remotely controlled hydraulic cylinders. A vertical leg is rigidly fixed at the free extremity of each horizontally extensible arm and the leg is provided with a cantilevered foot carrying a support plate keel of the boat to be hoisted. The hanging of the balance on the crane's hook is implemented by means of a suspension carriage running along the central longitudinal beam of the balance, the longitudinal position of which may be remotely controlled by the operator by means of a hydraulic cylinder. A mechanism for rotating the suspended load in respect to the crane is also disclosed.

Abstract: A powered method and apparatus for raising and lowering a boat in a boat lift with quick connection to and use of the boat battery to power a DC electric motor on the lift. A method of converting a manual lift to a powered lift is provided. The lift drive has a tractive drive unit with a friction wheel and the motor and a reduction drive, a drive unit subframe, a drive unit mount adjustable on the frame of the lift, adjustment structure to locate the subframe in a desired position in any one of a variety of boat lifts and with respect to a variety of manually operable lift actuator wheels, structure to resiliently bias the friction wheel against the actuator wheel, structure to stably remove the friction wheel from the actuator wheel, a quick connector for connection to a boat battery, and a switch for selective control of motor operation and direction of rotation.

Abstract: A storage facility for units, such as boats, consists of a multi-story rotatable tower having radial storage region opening to exterior of the tower, and an elevator tower fixed adjacent the exterior of the tower. The elevator tower includes a lift car having fingers movable beneath a unit to be lifted and also movable substantially radially from a retracted position to an extended position enabling units to be inverted into or removed from the storage regions and lowered to or raised from a loading/unloading station at the base of the lift tower.

Abstract: Boat cradle and storage construction including a plurality of substantially identical support units each availing of a central column comprising a support element and brace parts connected to the column and a base member of chevron shape with an adjustable ram in the column extending upwardly, and a pad at its end to engage the bottom of a boat or the like, the arrangement of the column and brace parts being such as to reduce space required for storage of the units when not in use and yet the base member shape provides stability, the arrangement of the brace parts being important from the standpoint of the overall assembly.

Abstract: An elongated operating cylinder has an internal piston assembly including axially spaced diametral disks. Such assembly is movable lengthwise in the internal cavity of the cylinder. A flexible force-transmitting component is connected to the piston assembly and extends axially of the cylinder through one of its ends. Introduction of fluid under pressure into the cylinder cavity tends to move the piston assembly axially so as to apply a pulling force to the flexible force-transmitting component, adapting the cylinder for use as a fluid-pressure actuator. Such fluid pressure actuator is particularly suited for use in lift apparatus where a compact, stationary frame has upright rails along which a lift carriage is movable. The lifting force preferably is provided by the flexible force-transmitting component of the actuator which can be routed by one or more pulleys. The lift apparatus can be mounted adjacent to a dock for lifting a small watercraft from the water.

Abstract: A stationary rectangular base frame is mounted underwater and supports generally upwardly extending, swingable, parallel links or arms. A lift platform or lift pads are supported at the upper end portions of the arms and, in combination with the base frame and arms, form one or more upright parallelograms. A hydraulic jack is connected extending generally diagonally of the parallelogram arrangement and has a plunger for swinging the arms to translate the lift platform or pads up to remove a watercraft from the water or down to lower the watercraft back into the water.

Abstract: A lifting device for small boats which is attached to the rear vertical surface of a larger boat. The device comprises at least two support units each having a hollow vertical tube to the boat and a vertical extension tube movable in the hollow attached tube. Extending from the vertical tube is a horizontal support so that a pair of such supports holds the small boat transversely. The vertical extensions are moved by motor-driven cables.

Abstract: An apparatus for the adjustment of the water level in a lock comprises at least one fluid chamber arranged on a bottom or a bottom and a sidewall of a lock room between lock gates. The adjustment of the water level is performed by the supply and discharge of air in the fluid chamber through an air supply and discharge pipe.

Abstract: An apparatus for elevating objects and consisting of a frame for bearing on a subjacent support surface for the apparatus, a platform having an upwardly facing surface for bearing against an object to be elevated and laterally spaced sides and mounted to the frame for movement relative to the frame in a vertical direction between a lowered position and a raised position, a flexible cord, a winch mounted on the frame for selectively retrieving and paying out the cord, an elongate hollow conduit with spaced opposite ends mounted to the platform so that the conduit length is aligned laterally with respect to the platform, and wherein the cord extending from the spaced opposite ends of the conduit is connected to the winch and frame so that as the line is retrieved by the winch a lifting force is exerted on the conduit to elevate the platform.

Abstract: A boat hoist for raising and storing boats mounted on legs resting on the bottom and a pair of parallel angled swing leg assemblies raising a boat support rail member mounted on the upper ends thereof, with a fluid pressure actuator powering elevation of a swing leg assembly to raise a boat on cradle supports mounted on the rail member. A bow post carrying cradling rollers is pivoted to the forward end of the rail member, spring biased into an upright position to facilitate centering of the boat during the approach to the hoist. Adjustable height inwardly inclined feet support the support frame on the bottom surface.

Abstract: A boat lift assembly wherein the use of a conventional cable system has been replaced with a screw drive assembly. The screw drive assembly eliminates all the safety hazards which accompany a cable operated system. Additionally, the use of aluminum components is extensive throughout to keep corrosion to a minimum. Further, Teflon and Lexan wear strips are used to eliminate friction problems between the relatively moving members.

Abstract: A boat lift for installation in a boat well in a boat dock between the opposing sides of the boat well to lift a boat out of the water and lower a boat into the water. The boat lift comprises a frame adapted to receive and support a boat, at least one pontoon mounted on the frame and adapted to be flooed and evacuated to lower and raise the frame, and a pair of forward and rearward supports on the frame. Each of the supports is supported between a pair of rollers on a mounting bracket on the side of the boatwell, the brackets supporting the supports so that the frame is sloped with the back of the frame being elevationally above the front of the frame.

Abstract: According to the invention, a lift is provided having base beams, first and second pairs of lifting arms and lifting rails. The lifting arms have one end pivotally mounted to the base beams for rotation about parallel axes with the common plane of the axes residing substantially in a horizontal orientation. The other ends of the lifting arms pivotally connect to the lifting rails to define, when viewed from the side, a closed linkage that permits the lifting rails to be raised and lowered relative to the base upon the lifting arms being simultaneously pivoted. The bow pair of lifting arms are longer than the stern pair of lifting arms, and the distance between the pivots on the base beams is greater than the distance between the pivots on the rails so that the linkage cannot lock-up when in the loading position and so that a craft resting on the rails is inclined with the bow above the stern for drainage.

Abstract: The present invention sets forth an hydraulically operated boat lift for lifting small boats upwardly out of a body of water by simultaneously supplying water pressure to four support posts connected to four corner portions of a lifting frame. Each of the corner posts comprises an hydraulic cylinder with the cylinder body connected to the lifting frame and moveable vertically on its downwardly extending piston rod which forms support legs for the lift.

Abstract: A boat lift includes a pair of straps or ropes which are secured at one end at intermediate elevations along a pair of horizontally spaced upright standards. The straps extend downwardly beneath a boat and then upwardly where they are secured about pulleys mounted on a horizontal shaft journaled at the top of the standards. Rotation of the shaft by a handwheel will shorten the straps and lift and completely overturn the boat.

Abstract: A remote controlled boat lift comprises a remote transmitter unit that can selectively transmit one of two pre-determined RF signals, an up receiver and down receiver connected to operate a pressure pump system and valves for selectively inflating and deflating a pontoon supported framework for docking a boat.

Abstract: A boat shoring system for cradling and supporting a boat in dry storage comprising two or more interconnected sub-system assemblies. Each sub-system comprises a central load bearing post and two laterally spaced outside supporting stands securely interconnected with laterally adjustable and angularly directed cable or chain means tautly stretched and preferably in tension to stabilize lateral movement. Two adjacent sub-systems are further stabilized by tautly stretched center cable means. The load bearing posts and outside supporting stands are vertically adjustable and transversely movable both laterally as well as forwardly and rearwardly. The boat shoring system can be easily assembled for use or dismantled into individual components and compactly stored during non-use.

Abstract: A system for storage and shipping of boats availing of a series of adjustable support units which are connected by flexible elements to each other to prevent lateral and longitudinal movement of the boat with respect to its supported location, the support units likewise providing for fastening of a boat to the units by other flexible elements.

Abstract: A shiplifting device comprising a platform (1) submersible in a basin and having a deck (2) and a downwardly open lifting skirt (3) positioned below the platform. The shiplifting device supplies and removes air from the lifting skirt and link arms (4, 4') connecting the platform with the quay or parts associated therewith, each link arm at mutually separated points being pivotally connected with the platform and the quay about a substantially horizontal axis of rotation (5, 6; 5',6'), so that the platform maintains its horizontal orientation. The link arms provide buoyancy, and the centers of buoyancy (7, 7') of each moves between a first area in the immediate vicinity of a horizontal plane through the axis of rotation (6, 6') of the link arm (4, 4') in question relative to the quay, and a second area in the immediate vicinity of a vertical plane through the same axis of rotation (6, 6').

Abstract: A watercraft lift supported on one or a pair of stanchions that include a sleeve assembly mounted for slidable movement on the stanchions. A platform is mounted on forks carried by a cross arm inserted into the sleeve assemblies which protrude out from the stanchions. Upright members mounted on the platform carry fender members.In a modified form of the invention a single stanchion with a similar sleeve assembly, a cross arm and twin forks, lifts a floating dock.In a further modified form, a single stanchion with a similar sleeve assembly, a cross arm and twin forks, lifts a non-floating dock.In still another modified form a single stanchion with a sleeve assembly cross arm and twin forks carries a spaced frame for receiving a seaplane.

Abstract: A series of simple detachable frames, fitted between a floating body and its' mooring support structure, will provide static stability to the floating body, by restraining all movements--except those occurring vertically under tides and buoyancy lift, and to which movements it will provide vertical guidance. Called "Stabilizer for Floating and Submersible Structures," many uses are anticipated for the device. Among these are: pontoon lift docks, where it will eliminate the need for winches and their lift cables or chains, as well as their support piers; ocean-bed exploratory structures, where it will create a new type of stabilized oil-drilling platform and transfer shuttle; and for water craft at mooring, a safer securing system to replace conventional mooring lines.

Abstract: A boat lift for a berth having permanently positioned piles in pairs spaced apart a distance sufficient to permit the boat to be berthed thereat to move between the paired piles while in the water includes a cradle having fore and aft transverse members upon which the boat is supported out of the water, a first pair of such piles equipped with first sheaves, a second pair of such piles with second sheaves, a third pair of such piles positioned between the first and second pairs adjacent the second second pair, first and second beams carried by the inside and outside piles of the second and third piles, motor driven winch drums supported by the first and second beams, third sheaves carried by the first and second beams, first inside and outside cables reeved respectively from the first and second drums via the first and second sheaves forward to the inside and outside piles of the first pair to lift the fore transverse member of the cradle, and second inside and outside cables reeved from the winch drums via t

Abstract: A boat lift includes a vertical H-beam driven into the floor of a body of water adjacent a pier. A shaft housing surrounds the H-beam and slides up and down it on rollers mounted within the channels defined between the opposed flanges and web of the H-beam. A fork lift-like boat support is mounted to the shaft housing for vertical movement therewith to raise and lower a boat to and from the water. Forces are transferred from the shaft housing to the H-beam by the rollers engaging the web surfaces and the inner flange surfaces. A hoist, supported by the pier and the top of the H-beam, raises and lowers the shaft housing and boat support therewith.