Boat propulsion system, and control device and control method therefor

A control device for a boat propulsion system, the control device comprising:

• a power source arranged to generate a rotational force;
• a boat propulsion section having a propeller arranged to be driven by the rotational force and to generate a propulsive force;
• a shift position switching mechanism disposed between the power source and the propulsion section and arranged to switch among a first shift position, a second shift position in which the rotational force of the power source is transmitted to the propulsion section in a direction opposite to that in the first shift position, and a neutral position in which the rotational force of the power source is not transmitted to the propulsion section;
• a gear ratio switching mechanism disposed between the power source and the propulsion section and arranged to switch a gear ratio between the power source and the propulsion section between a low-speed gear ratio and a high-speed gear ratio;
• and
• an actuator arranged to drive the shift position switching mechanism and the gear ratio switching mechanism;
• wherein
• when switching is to be performed from the neutral position to the first shift position and the high-speed gear ratio, the actuator is arranged to, when the current gear ratio of the gear ratio switching mechanism is the low-speed gear ratio, maintain the low-speed gear ratio, then switch to the first shift position, and then establish the high-speed gear ratio;
• and
• when the current gear ratio of the gear ratio switching mechanism is the high-speed gear ratio, to establish the low-speed gear ratio before switching to the first shift position, then switch to the first shift position, and then establish the high-speed gear ratio.

A control method for a boat propulsion system, the boat propulsion system including:

• a power source arranged to generate a rotational force;
• a boat propulsion section having a propeller arranged to be driven by the rotational force and to generate a propulsive force;
• a shift position switching mechanism disposed between the power source and the propulsion section and arranged to switch among a first shift position, a second shift position in which the rotational force of the power source is transmitted to the propulsion section in a direction opposite to that in the first shift position, and a neutral position in which the rotational force of the power source is not transmitted to the propulsion section;
• a gear ratio switching mechanism disposed between the power source and the propulsion section and arranged to switch a gear ratio between the power source and the propulsion section between a low-speed gear ratio and a high-speed gear ratio;
• and
• an actuator arranged to drive the shift position switching mechanism and the gear ratio switching mechanism, the control method comprising:
• causing the actuator to maintain the low-speed gear ratio when the current gear ratio of the gear ratio switching mechanism is the low-speed gear ratio, switch to the first shift position, and then establish the high-speed gear ratio when switching is to be performed from the neutral position to the first shift position and the high-speed gear ratio;
• and
• causing the actuator to establish the low-speed gear ratio before switching to the first shift position, switch to the first shift position, and then establish the high-speed gear ratio when the current gear ratio of the gear ratio switching mechanism is the high-speed gear ratio.