
Pirates didn't want big ships, and they didn't want to fight at all. They were smarter than that. They hid in shallow rivers and marshes, so they needed small boats that weren't very deep. They darted out very often at night and took larger boats by surprise so they needed fast,easy to maneuver ships. Pirates wanted weatherly boats, usually sloops or schooners that could sail closer to the direction of the wind than the heavy, square-rigged warships sent to capture them.
Pirates didn't make long voyages like the Royal Navy. Their trips were short, often only a few days. Pirates didn't want to match their little boats guns with the navy's big guns, so they counted on surprise, by boarding the prize in a yelling, furious rush. When they traveled, pirates were packed into small boats like dogs in a kennel.
Pirates were scalawags and scoundrels but, mostly they were sailors. They were clever planners, too. They chose fast, nimble ships that could swoop quickly down on merchant vessel and get away from men 0' war trying to catch them.
What was so specialabout pirate schooners, they were weatherly. This means they could sail a little closer to the direction from which the wind was blowing. No sailing vessel can move directly into the wind. To get from point A to the dock at point B, both ships must sail back and forth, first with the wind on one side, then turning to put the wind on the other side. A big square rigged ship like the big man 0' wars the Royal Navy sometimes sent to catch pirates could only sail ten or fifteen degrees toward the wind. Pirates mostly sailed schooners or sloops, which could sail thirty or forty degrees toward the wind.
Look at the angles, The big ship must sail almost three times the distance the schooner sails to reach the same place. On the open sea, the pirate ship could easily out run the frigate to windward. The man o' war would never catch it, pirates would be home free.