For the person wanting to know about building a "classic" pirate ship...

All sorts of ships were used, and pirates today still exist, mainly around
SE Asia, and Bangladesh areas.

Pirates usually didn't have alot of resources, so they were often left with
purchasing older, smaller ships, or whatever they could take or steal.
Sloops were common, as well as small merchant vessels with 1 or 2 masts,
converted with light cannon and/or swivel deck guns. A sloop was a very
small ship, much like the racing sailboats today, fast, and very light. The
sloop was favored also because she didn't need a large crew, and could
easily flee if trouble came.

Sloops had a single mast, mounted typically from 8 to 12 cannon (4 to 6 per
side), and were sloop-rigged, and could carry some swivel guns as well.

You can do a search online for "pirate sloop", or "sloop-rigging" to get an
idea of what such a ship might look like.

In the Mediterranean, the Xebec was a good ship for pirates, also a
reasonably light and fast ship. The Xebec could mount cannon similar to the
sloop, plus carry swivel guns for boarding. Xebecs are lateen-rigged. For
a very good idea what lateen-rigging looks like, check out Columbus' ship
the Nina.

Ships like these required alot of wood to construct them, so replicas of old
naval ships today are often built slightly smaller than original. You'll
need alot of funds to construct a full-size large ship, although a small
ship like the sloop, or possibly a Xebec could be built if you've got alot
of time on your hands and live in an area with a steady supply of good
quality woods.

http://www.geocities.com/xebecinc/index.html

This site is helpful for learning more about the Xebec ships. It is helpful
to know that the British, French, Portuguese, Russians, and many others used
Xebecs or Xebec-types from time to time. Thus it's a good ship to consider
if you're serious about building.

Let us know if you need more info.

Keep in mind, size-wise, most of these ships needed a fairly large crew by
today's standards, and were quite large, up to 100 feet or so.