The wreckages of Blackbeard's flagship Queen Anne's Revenge is now displayed at the North Carolina Maritime Museum.

What they revealed was the arsenal of fearsome weapons he used on his victim ships.

The archeological findings and displays in North Carolina reveal that he fired nine-inch nails and glass (in addition to the cannon ball) from cannons.  He also had two cannon balls linked by a chain, which upon firing would produce a spin.

Discovery News also reported that Blackbeard put nails and glass with gunpowder into bottles with a wick (essentially a pirate version of the Molotov cocktail).

Blackbeard was clearly going for splash damage. 

Mark Wilde-Ramsing, deputy state archaeologist and leader of the expedition, told Discovery News that Blackbeard didn't want to sink the ships.  Instead, he wanted to intimidate the victim ship's crew into surrendering and then plunder ship's goods.

Shooting bolts and scrap lead, iron and glass would have been very effective [to that end], said Wilde-Ramsing.

Blackbeard, born Edward Teach, was a notorious British pirate who plundered in the waters near the American colonies and West Indies in the early 1700s.  After his death, his fame grew and was subsequently referenced in numerous works of fictions, including the Pirates of the Caribbean film series.