Thruster system for marine vessels

1. A method of operating a thruster system of a boat, the method comprising:

receiving, at a controller, a helm input indicating operation of a primary steering mechanism of the boat in a port or starboard direction to impart a turning movement to the hull, the primary steering mechanism not including the thruster system;

automatically operating the thruster system with the controller to supplement the turning movement corresponding to the helm input; and

receiving, at the controller, a speed input indicative of a boat speed;

wherein automatically operating the boat thruster with the controller to supplement the turning movement corresponding the helm input includes varying a thruster speed based on the speed input.

2. The method of claim 1 , wherein the primary steering mechanism includes a rudder and the helm input is derived from a rudder position.

3. A method of operating a thruster system of a boat, the method comprising:

receiving, at a controller, a helm input indicating operation of a primary steering mechanism of the boat in a port or starboard direction to impart a turning movement to the hull, the primary steering mechanism not including the thruster system; and

automatically operating the thruster system with the controller to supplement the turning movement corresponding to the helm input;

wherein automatically operating the boat thruster with the controller to supplement the turning movement corresponding the helm input includes:

receiving, at the controller, a direction input indicating forward or aft operation of the boat;

if the direction input indicates forward operation, operating the thruster system to supplement the turning movement opposite the port or starboard direction of the helm input; and

if the direction input indicates aft operation, operating the thruster system to supplement the turning movement toward the port or starboard direction of the helm input.

4. The method of claim 3 , wherein the direction input is derived from a throttle position of the boat.

5. The method of claim 1 , wherein the helm input also indicates a magnitude of operation of the primary steering mechanism in the port or starboard direction.

6. A method of operating a thruster system of a boat, the method comprising:

receiving, at a controller, a helm input indicating operation of a primary steering mechanism of the boat in a port or starboard direction to impart a turning movement to the hull, the primary steering mechanism not including the thruster system; and

automatically operating the thruster system with the controller to supplement the turning movement corresponding to the helm input;

wherein the helm input also indicates a magnitude of operation of the primary steering mechanism in the port or starboard direction; and

wherein automatically operating the boat thruster with the controller to supplement the turning movement corresponding the helm input includes initiating operation of the boat thruster after the magnitude of operation of the primary steering mechanism exceeds a predetermined input threshold.

7. A method of operating a thruster system of a boat, the method comprising:

receiving, at a controller, a helm input indicating operation of a primary steering mechanism of the boat in a port or starboard direction to impart a turning movement to the hull, the primary steering mechanism not including the thruster system; and

automatically operating the thruster system with the controller to supplement the turning movement corresponding to the helm input;

wherein the helm input also indicates a magnitude of operation of the primary steering mechanism in the port or starboard direction; and

wherein automatically operating the boat thruster with the controller to supplement the turning movement corresponding the helm input further includes varying a thruster speed based on the magnitude of operation of the primary steering mechanism.

8. The method of claim 1 , wherein varying the thruster speed based on the speed input includes decreasing thruster speed when the boat speed increases.

9. The method of claim 8 , wherein varying the thruster speed based on the speed input further includes ceasing thruster operation above a predetermined upper boat speed threshold.

10. A method of operating a thruster system of a boat, the method comprising:

receiving, at a controller, a helm input indicating operation of a primary steering mechanism of the boat in a port or starboard direction to impart a turning movement to the hull, the primary steering mechanism not including the thruster system;

automatically operating the thruster system with the controller to supplement the turning movement corresponding to the helm input; and

receiving, at the controller, a ballast input indicative of a ballast level onboard the boat;

wherein automatically operating the boat thruster with the controller to supplement the turning movement corresponding the helm input includes varying a thruster speed based on the ballast input.

11. The method of claim 10 , wherein varying the thruster speed based on the ballast input includes automatically increasing the thruster speed when the ballast input is above a predetermined level threshold.

12. The method of claim 1 , further comprising receiving, at the controller, an input from a user interface to disable automatic control of the thruster system.

13. The method of claim 12 , further comprising operating the thruster system based on manual control inputs with automatic control of the thruster system disabled.

14. The method of claim 13 , wherein the manual control inputs are received from a joystick.

15. The method of claim 13 , wherein the manual control inputs are received from a joystick.

16. The method of claim 13 , wherein the manual control inputs are supplied to a drive of the thruster system directly.

17. The method of claim 13 , wherein the manual control inputs are supplied to a drive of the thruster system through the controller.

18. A boat comprising:

a hull;

a primary steering mechanism carried by the hull;

a thruster system carried by the hull, the thruster system including:

at least one stern thruster mounted to the hull; and

a controller receiving configured with program instructions to operate the at least one stern thruster responsive to control inputs;

a first exhaust port positioned to vent engine exhaust below a hull waterline at the stern;

a second exhaust port, separate from the first exhaust port, positioned to vent engine exhaust; and

a crossover device configured to automatically switch an exhaust vent path between the first and second exhaust ports;

wherein the crossover device is configured to automatically switch between the first and second exhaust ports to prevent thruster cavitation during operation of the at least one stern thruster.

19. The boat of claim 18 , wherein the second exhaust port is positioned above the hull waterline.

20. The boat of claim 18 , further comprising:

a primary steering mechanism carried by the hull, the primary steering mechanism being distinct from the at least one stern thruster;

a control station located on the hull; and

a helm located at the control station, the primary steering mechanism being operable via the helm and a helm input being derived from operation of the primary steering mechanism by the helm;

wherein the controller is further configured with program instructions to operate the at least one thruster responsive to the helm input to supplement a corresponding movement of the hull.

21. The boat of claim 18 , wherein the controller is further configured with program instructions to direct the crossover device based on operation of the at least one stern thruster.