As a .5 product, Tower of the Black Pearl was originally written for the pre-DCC Dungeon Crawl Classic line of adventures, for D&D/d20/OGL/whatever gameplay. Not surprisingly, then, it's more of a generic FRPG module, than an epic-swilling Harley Stroh DCC adventure. Unfortunately, while it's a good generic module, it's not as vivid as the Michael Curtis DCC adventures, either.
The plotline is that once every 100 years (or whatever), The Tower of the Black Pearl surfaces for only eight hours. However, a group of pirates arrive first, and the PCs have to deal with them as well as the Tower. The adventure has twelve areas, and is a standalone adventure. If you're looking for a longer more developed pirate-y adventure, I highly recommend the TSR / WotC Underwater Saltmarsh series, starting with U1: Secret of Saltmarsh.
[3 of 5 Stars!]