Control of a waterjet propelled vessel

A method for calculating a heading of a watercraft, comprising:

• acquiring a heading of the watercraft at a base time;
• acquiring a heading turn rate from an angular rate of turn sensor of the watercraft at a later time;
• determining whether the acquired heading is believed accurate at the later time;
• if the acquired heading is believed inaccurate, calculating a heading of the watercraft based on the heading turn rate and the originally acquired heading;
• outputting the calculated heading for control of the heading of the watercraft.

A method for correcting a heading of a watercraft, comprising:

• measuring an amount of error induced by the effect of at least one of a magnetic, electrical and vibration/shock disturbance on at least one of x, y and z heading data from a heading sensor;
• acquiring at least one of x, y and z heading data from a heading sensor;
• determining whether the at least one disturbance is occurring;
• correcting the heading data in the occurrence of a disturbance by adding a correction value to the heading that offsets the measured amount of error induced by the disturbance;
• outputting the corrected heading data for control of the heading of the watercraft.

A method for controlling roll out of a watercraft, comprising:

• determining whether a steering apparatus is off center to alter a position of a nozzle of the watercraft;
• if the steering apparatus is off center, setting a nozzle position command to a steering command from the steering apparatus;
• determining whether the steering apparatus has been returned to a center position;
• if the steering apparatus has been returned to a center position, setting the nozzle position command to oppose a turn of the watercraft.