 That same year he rejoined the Dutch merchant fleet and steadily worked his way up through the posts of boatswain and chief mate before becoming a merchant ship's master at the age of thirty.Although having had little formal education, he spoke tolerable French and fluent English.Bruijn notes that an anonymous English biographer of De Ruyter claims that he was active in Dublin between 1623 and 1631 as a factor for the Vlissingen-based merchant house of the Lampsins brothers and had become fluent in English when living there.