I am curious as to how 'legal' piracy was conducted by the English during their blockades in the 18th century (against the French). How would they approach a ship? How would they hold the other crew? Would they loot a ship? Where these actions conducted by semi-legal privateers? Was it in any way degrading as the victims made it out to be? How long would they be captured?
I've written about blockade before, which may be of interest to you:
But I think you may be confused a bit in your usage of terms. Pirates are by definition operating illegally; they are criminals. Blockade by national ships during time of war is perfectly legal, as is privateering -- a privateer's letter of marque or letter of reprisal authorizes (gives legal protection to) the privateer's action. Could you maybe expand a bit on your question?