Final answer:
To steer away from the dock if pushed back by wind or current, use the rudder.
Step-by-step explanation:
If the wind or current pushes you back onto the dock while leaving it, the correct action to take is to use the rudder to steer away. This involves turning the boat's rudder in the opposite direction of the wind or current, which will help to steer the boat away from the dock. Increasing speed or engaging reverse can actually make the situation worse by causing the boat to collide with the dock or other objects. Additionally, sounding a prolonged horn blast may be a safety precaution in some situations, but it is not the most appropriate response to this specific scenario.