A dispatch (PDF) from the pirate-filled waters off Canton (present-day Guangzhou). The parallels to modern accounts from Somalia are pretty eerie, especially when you consider that China was undergoing its own brand of internal turmoil during this period:
The pirates, who have always been very numerous and very formidable in these waters, have lately increased to an alarming extent. No sufficient punishment has been inflicted on them, and they have grown audacious beyond measure. They muster by thousands and sometimes go in fleets of sixty and seventy junks. Scarcely any merchantman entering here are safe from assault, and the people of Hong Kong are even apprehensive of an attack on the town.
Read the whole thing. Matters get quite hairy toward the end, when the Porpoise starts flinging 32-pounds cannonballs at the pirates.