Had another thought of terminology.
Ship
Strictly speaking, the term ship only applies to boats with at least three fully square rigged masts. I've been using the terms ship and boat somewhat interchangably here. First-rate through to sixth-rate ships, I believe, depend on tonnage and number of guns carried. First-rate being the largest and with the most guns.
There are plenty of good resources on what non-ships are called, dependant on their rigging types. I'll post a link when I find a good one.
Yacht, while not necessarily a modern term, tends to refer to an unarmed sailing vessel of fore/aft rigging design. Sloops and Cutters can be referred to as yachts but, in this time setting, generally aren't.
A Dinghy is a very small boat, usually one to four personed and a single mast. Readily capsizable as proved by many dinghy sailors the world over!!!

As a credit to this, I'm going to give you the definition of the term turtling.
Turtling
A dinghy sailing term referring to when the boat is fully inverted ie the mast is pointing down to the seabed. This usually happens if a capsize is not righted fast enough. It is so called because the inverted hull sticking out of the water looks like a turtle shell. In Pirates of the Caribbean: At Worlds End, when they invert the Black Pearl (and for a sailor that scene is fantastic to watch! Very funny, see below) it can be said to be turtled.
In my sailing club, it is almost a running joke that turtling is the sign of a bad sailor and, as a consequence, we present a prize, to the person who has capsized the most in the year, of an inflatable turtle! This all has nothing to do with PotBS, of course, but a fun story to tell nevertheless!