Pirates changed their ships as easily as they changed their captains.
In the early days of the Age of Piracy, vessel changes were numerous and rapid. The buccaneers began with a canoe or rowing-boat, and used it to capture a larger boat; using this they captured a small ship, and with the small ship they captured a bigger ship. Each vessel taking profitted with a larger one.
With a few exceptions, pirate ships were not built as such, but were converted merchant ships. Experienced sea-captains could spot them by their raised gunwales, which gave their crew better protection in battle.
Often, many of the crew had to sleep on deck in all weathers, for the ships were always overcrowded.