Maclear entered the Navy in September 1851 as a cadet on board the frigate , then bearing the broad pennant of Commodore Christopher Wyvill, then commanding the Cape station. In her he saw service during the Xhosa Wars in 1851, and afterwards, as a midshipman of , served in the Baltic and in the Black Sea from 1854 to 1856, receiving, the Baltic, Turkish, and Crimean medals, with the clasp for Sevastopol. He passed his lieutenant's examination in July 1857, and served on board in the Red Sea as mate during the outbreak at Jeddah in 1858.