Abstract: A boat trim control system that includes a pair of trim tabs pivotally mounted to the stern of a boat hull, and an engine responsive to application of electrical ignition power for powering the boat through the water. A pair of fluid actuators extend between the hull and the respective trim tabs for selectively and adjustably moving the tabs between fully extended and fully retracted positions. A fluid drive is responsive to a boat operator for selectively adjusting positions of the trim tabs independently of each other to maintain a desired attitude of the boat hull. Electronic control circuitry is responsive to removal of ignition power from the engine for operating the fluid drive and energizing the actuators for a predetermined time duration so as to move boat trim tabs to the fully retracted positions upon removal of ignition power from the engine.

Abstract: An apparatus for influencing the position of a boat in water, with trim flaps disposed on either side of the longitudinal axis of the boat, the flap angles of said trim flaps always being adjustable by a drive with a control device, which acts upon all the flap drives in dependence on a central control switch, which comprises several control contacts assigned to the tilting directions of the boat.In order to control the position of the boat in the water automatically, the apparatus is designed so that the control switch comprises at least one movable, gravity-dependent contact-making body, which automatically activates the control device via the control contacts when the boat tilts.

Abstract: At least two trim tabs 12 are mounted on the transom 11 symmetrically on each side of the longitudinal axis of the hull 10. Each trim tab 12 includes a plate 15 mounted on at least two rocker arms 16 for pivotal movement relative to the transom 11 and two or more hydraulic actuators 20 and 21 for pivoting the plate 15 relative to the distal ends of the rocker arms 16.

Abstract: A resilient trim plate which, when mounted in cantilever fashion on the bottom of a boat and when adjusted, provides for trimming of the boat when the boat is underway and moves over the water. The trim plate is provided with fasteners for rigidly securing the forward portion of the trim plate to the bottom of the boat at a location forwardly of the transom or aft end of the boat. The trim plate extends rearwardly from the attachment means in cantilever fashion and presents a curved or convex lower surface to the water. The curvature of the lower surface of the trim plate can be increased or decreased to thereby increase or decrease the pressure difference between the upper and lower surfaces of the trim plate when the boat is moving over the water. Such pressure difference generates a downward force on the trim palte and thereby the boat much in the same manner the creation of a lift force as air flows over the wing of an airplane in flight.

Abstract: An improved trim-tab control for boats has for each trim tab a yoke movably secured to a frame, a mechanical link between the yoke and the trim tab such that yoke and trim tab move in unison, a lever pivotable mounted with respect to the yoke and having first and second engagement surfaces, and a pair of switches on the yoke positioned for selective engagement with the lever surfaces to actuate a hydraulic device for moving the trim tab in opposite directions. Tab adjustment is carried out by continuing movement of the lever with respect to the yoke, while the yoke moves in response to such adjustment. A scale is secured adjacent to the lever such that the lever position provides visual indication of the trim-tab position.

Abstract: A mounting assembly for an outboard motor includes a motor mount having a transom mounting bracket attachable to a boat transom and a motor supporting bracket spaced aft of and pivotally connected by upper and lower links with the transom mounting bracket to support an outboard motor wholly aft of the boat transom, a cylinder for moving the motor supporting bracket relative to the transom mounting bracket to raise and lower the outboard motor, and a trim plate disposed beneath the lower link and connected to the motor supporting bracket for movement with the motor supporting bracket to provide a lifting force on the rear of the boat during forward movement of the boat. Preferably, the trim plate is disposed in parallel relation to the lower link having its fore end pivotally connected to the boat transom and its aft end pivotally connected to a bracket extension member projecting from the lower end of the motor supporting bracket.

Abstract: A marine drive (2) is provided with an anti-ventilation plate (22) having a forward horizontal portion (24) and an aft portion (26) extending downwardly at an angle (28) to horizontal and noncoplanar with the forward portion (24). An adjustable anti-ventilation plate (30, 58) is also provided. The preferred form of the adjustable anti-ventilation plate is particularly simple and readily added to existing structure.

Abstract: A trim tab indicator system comprising a pair of trim members hinged to the stern of a boat, one of each side of the center line of the boat and a hydraulic cylinder individual to each trim member having a first head at one end and a second head at the other end. The cylinder includes a piston and a tubular shaft connected to the piston and extending through the first end of the cylinder. A bracket is connected to the first head and has a surface complementary to the transom of the boat and is mounted on the transom. A tubular coil is fixed on the first head and extends axially within the cylinder, and a floating rod of magnetically permeable material is provided in the tubular shaft with a lower end engaging the base of the tubular opening of the shaft with its upper end extending into the coil such that movement of the trim tab changes the inductive relationship between the rod and the coil to provide a signal representing the position of the tab.

Abstract: A boat leveling systems with a pair of trim tabs pivotal between a horizontal position and a downwardly inclined position. Each trim tab is actuatably between the horizontal and inclined positions by a separate fluid motor which includes a cylinder, a piston slidably disposed in the cylinder and a rod connected to the piston. The position of each trim tab is indicated by apparatus which includes a linear potentiometer attached to the rod of the associated fluid motor, the potentiometer having a flexible plastic envelope and a pair of normally spaced-apart conductive strips sealed in the envelope, a ball and spring carried by the cylinder for contacting the envelope and forcing the strips into electrical contact with each other, and a resistance measuring device connected in circuit with the potentiometer and to provide a readout in degrees of the downward angle from horizontal of the trim tab.

Abstract: An improved trimming arrangement is disclosed which is particularly suited for use with a craft having planing hull with a marine drive. In one embodiment, the trimming arrangement includes a submerged trim hydrofoil which is affixed to the drive housing of the drive system beneath the screw propeller drive shaft. So that the efficiency of the planing hull and drive system are improved at hull-planing speeds, the trim hydrofoil is positioned to create a downward force component of the stern of the planing hull during forward movement through the water. The bow of the hull is thereby urged upwardly, thus minimizing the wetted area of the hull and improving its efficiency. In a further embodiment, the trimming arrangement includes a selectively adjustable submerged hydrofoil pivotably mounted to the transom of the planing hull which is operable to provide the desired downward force component on the stern of the hull.

Abstract: An attachment for forming a rearward extension of the hull of a boat is secured to a transom of the boat to form an extension of an underside portion of the hull and comprises a hollow body having a substantially flat surface and a bottom surface shaped to conform to the after end of the hull underside portion. A forward portion of the top surface of the hull extension is pivotally connected to the transom to allow pivotation of the extension between a lowered position, for cruising and rough weather conditions, and a raised position, for planing, in which the top surface of the hollow body is located adjacent the transom. A hydraulic piston and cylinder device is provided for effecting the pivotation of the hollow body.

Abstract: Essentially one-half of the circumference of the propeller of the marine vessel is arranged in a tunnel having a flow-favorable cross-sectional configuration which follows the flow lines of the water. At the starting region of the tunnel there is arranged a pivotable control plate which can be moved out of a retracted position where it lies in the surface of the tunnel into an extended position removed or remote from the aforesaid retracted position, in order to detach the flow of the water from the surface of the tunnel during rapid vessel travel. The propeller which is driven at a high rotational speed accordingly operates as a partially or semi-immersed propeller. The vessel floor and the control plate are interconnected by an elastically deformable cover plate which is secured to the vessel floor and the control plate in a bending or flexurally resistant fashion.

Abstract: Pitch of a vessel is controlled by trim tabs mounted on the stern of the vessel. The trim tabs are hinged along an axis transverse to the fore-aft direction of the vessel. A hydraulic system changes the plane of the trim tabs in response to a gyro-controlled servo system that senses changes in the fore-aft level of vessel. The trim tabs operate dynamically to maintain the fore-aft level substantially constant or within limits that effectively moderate the pitching motion of the vessel.