How do pirates sail?
The same way as everyone else
all pirates were pirates of freedom. they wanted freedom from their government and to sail were they please. the stole and plundered from harbors and navel ships to damage the government and also benefiting themselves with the loot. to pay for goods they needed, to keep the ship in top fighting shape and to hire more crew members if needed.
well yes if your ship is not a light class ship. In that case go to a shipwright by the docks, talk to him and click upgrade. Then you can choose what you want to change whether it be the color, emblem or what the sail is made of. But remember you will need gold and ship materials for changing what the sail fabric is.