William was schooled in the navy. He took part in the 260 ship expedition of 1544, which burned Leith and Edinburgh, and held the office of Keeper of the King's Storehouse at Deptford Strand. In 1545 he served in Lord Lisle's channel fleet; two years later he took part in Protector Somerset's expedition to Scotland and victory at Pinkie, and in 1549 an expedition to Guernsey and Jersey. In that year he was appointed Surveyor of the Navy, and in December as captain of the "Mynion" he captured the prize of a French ship, the "Mary of Fécamp", laden with sugar. A reward of £100 was to be shared out among the crew of 300. In 1550 he superintended the removal of the ships from Portsmouth to Gillingham in the Thames Estuary, Edward VI owed him £471 for a voyage to Ireland in 1552, and in 1553 he went on a voyage to the Levant.