I want to know the answer to the following question:
What does attaching a zinc disc to a ships iron rudder do?
All the background I'm provided with is that "Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.[note 2] Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion.". Is that enough to answer the question?
Answer: yes