Configuration of Gimbal

Hello all
We have built a boat with a 3-axes gimbal controlled by regular servos. The gimbal is working correctly, I mean it is compensating any rotation of the boat (nick, roll and yaw). At the moment the camera points to north all the time (as long as the gimbal can compensate). I would like to point it to the next waypoint (or a point of interest). How can I achieve this?

Best regards