 Sanders attended Nelson Street School but in 1894 , when his family moved to Takapuna , he shifted to Takapuna School . The school was close to Lake Pupuke , where he learned to sail . He earned the nickname Gunner Billy for his exploits with a small cannon that a classmate brought to school . He left school at the age of 15 , and due to the influence of his parents was apprenticed to a mercer in Auckland . He was not particularly interested in the profession and , desiring a career at sea , would go down to the wharfs to inspect the berthed ships and chat with their captains and crewmen . 
