Abstract: Adjustment is made of the position of a marine transportation system including a boat having a drive, a trimmable port tab and a trimmable starboard tab. The operation of the marine transportation system is monitored to provide an output distinguishing boat operation in an on-plane condition and boat operation in an off-plane condition, to provide an output distinguishing boat travel in a straight forward condition and boat travel in a turning condition and to provide an output distinguishing boat operation in a first heel condition in which the boat tilts to port and boat operation in a second heel condition in which the boat tilts to starboard. The port and starboard tabs are positioned at desired positions in response to the outputs. According to the embodiment, a heel adjustment operation of the boat is carried out during boat operation in an on-plane straight forward travel condition, only.

Abstract: A supporting device for an outboard motor comprises a stern bracket, and an outboard motor bracket. A guide is arranged to the stern bracket, and thrust and reverse rails are mounted thereto. The outboard motor bracket has one end supporting the outboard motor, and the other end including upper and lower arm portions. The upper arm portion is engaged with the guide, and the lower arm portion includes a thrust roller which is slidably engaged with the thrust and reverse rails.

Abstract: An outboard motor supporting arrangement of a boat includes a stern bracket fixed to a transom of the boat. The stern bracket is U-shaped, and has a flat bottom and left and right side walls extending upwardly from left and right ends of the bottom. Each side wall includes a slant section and a vertial section extending upwardly from an upper end of the slant section. In each side wall, there is further formed a projecting portion projecting outwardly, and extending longitudinally of the boat, for preventing water from be splashed on the outboard motor.

Abstract: An outboard motor supporting arrangement includes a stern bracket fixed to a transom of a boat, a lift member which supports the outboard motor and which is connected with the stern bracket so that the lift member is movable up and down and swingable together with the outboard motor, a vertically extending tilt cylinder which is connected between the stern bracket and lift member for causing the lift member to move up and down, and a pair of horizontally extending trim cylinders which are provided between the stern bracket and lift member, for causing the lift member to swing. Each trim cylinder is pivotally supported on the stern bracket, and a rear end of each trim cylinder is provided with thrust rollers which rolls on the lift member. Alternatively, each trim cylinder is pivotally supported on the lift member, and the front end is provided with the thrust rollers abutting against the stern bracket.

Abstract: A flexible duct is connected between the outboard motor and the hull transom, to supply air, fuel, power and control cables to the motor liftably and steerably attached to the transom, even when the motor sinks into water. To improve the durability of the flexible duct, that is, to allow the flexible duct not to be moved whenever the outboard motor is pivoted for steering operation, the air supply apparatus for an outboard motor comprises (a) a hollow steering shaft pipe fixedly supported near the transom; (b) upper and lower bearings, attached between the steering shaft pipe, for supporting the pivotal steering shaft of the motor; (c) a cylindrical cover for pivotably and slidably covering the upper end of the steering shaft pipe; and (d) a flexible duct connected between the transom and the fixed hollow steering shaft pipe.