Minimize the amount of time you spend viewing to 30 minutes.
If you have to keep changing direction, then the animals may be trying to avoid you and should be left alone.
Look out for other signs of disturbance, such as sudden, repeated or prolonged dives, frequent changes of direction, formation of tight groups that swim away from you, or aggressive slaps and slashes of tail flukes and flippers.
If you have cut your engines choose the right moment to restart them to avoid disturbance.
Move away slowly when leaving, keeping to the 4 knot speed limit until you are at least 100 meters away.