Captains use several kinds of ammunition to load their cannons, depending on situation. There are three basic types of ammo:
|Round Shots||to damage ship's hull|
|Dismantling Shots||to damage ship's sails and reduce its speed|
|Anti-personnel Shots||to reduce enemy's numbers|
In general, if you want to board a ship, you would use Dismantling Shots to slow it down and then Anti-personnel Shots right before the boarding, to kill off the crew. If you are not planning to board a ship, then you can go all the way with Round Shots to sink it.
Ammo for the cannons :
Solid Ammo : Multipurpose, but better than anything against the Hull.
Basic Round Shot: yer basic iron cannonball.
Heavy Round Shot: Heavy round shot has excellent penetrative power against ship hulls, but is far less effective at damaging crew or sails.
Bronze Round Shot: Heavy round shot made from bronze is more effective at penetrating ship hulls than iron shot.
Bar Shot: two iron hemispheres joined by a solid bar.
Chain Shot: two iron balls connected by a chain.
Star Shot: A dismantling shot made from multiple lengths of chain with balls at their ends, connected together, at the center, in a 'star' pattern.
Anti-Personnel Shot : Shotgun theory - extremely effective against crew, less so against other parts of the ship.
Langridge: the poor-man's canister shot. "Langridge" was a fancy name for "shove in lots of nails, gravel, clamshells - whatever" It wasn't terribly effective, but it was easy to come by.
Canister Shot: the standard anti-personnel shot. It was literally a can filled with little iron balls.
Grapeshot: a new ammunition development in the early 18th century, and still (theoretically) restricted to the navy in PotBs.