In other words, if one ship was attempting to intercept another, what factors determined whether or not the pursuer would successfully chase down their prey, or that the fleeing ship would successfully escape?
I understand what made a boat fast and that some boats were able to sail closer to the wind. However, I'm also wondering about the kinds of tactical decisions involved in a chase between two ships with roughly equal performance (in my head I'm imagining two sloops).
Also, were merchant sloops typically weighed down more than pirate ships? And if so, does this effect the max speed (I'm of the understanding that max speed is determined by length, not weight) or maneuverability?
Sorry if this is a really broad question, but I'm very interested in this kind of thing, and I'm finding it hard to find any info that gets this specific. Any info you can add is greatly appreciated!
The first point is that long-term chases between similar ships were relatively rare during the Golden Age, pirates were opportunists, and largely picked on vessels they knew they could defeat. It's important to remember that if a pirate ship became damaged they couldn't simply put into the nearest port in order to repair. The repairs would need to be carried out by the crew, often at sea or in a secluded anchorage, but most definitely without any facilities, taking damage was therefore to be avoided at almost all costs to pirate captains. Battles between vessels were therefore rare, finding a merchant ship powerful enough, and brave enough to fight a pirate ship didn't happen a lot. Pirates would also often fly false flags and only declare their intentions when close enough that escape was impossible.
If we now picture your chase between two sloops, the pirate sloop is almost certainly carrying more crew than the merchant sloop, and is therefore able to set and adjust sails faster. In a small vessel such as a sloop, able to sail relatively close to the wind especially by the standards of the time this can make a huge difference.
The pirate sloop may also carry more sail, and would often have had bulkheads cut away, allowing the stowage of more weapons. Even with the additional weight of weaponry the pirate ship is lighter than a loaded merchant sloop. This means it has a smaller displacement, less draft and there is consequently less resistance, making it faster and more manoeuvrable.
I would finally add that the sloop, as a ship type in the early 18th century encompasses an enormous variety of ships. Most merchant sloops carried a single mast, some naval sloops carried two masts, the main rigged with a mainsail and a topsail, these sloops could carry up to 12 guns, but the vast majority mounted 6 or less.
I hope this at least goes some of the way towards answering your question.