Pirates and powderkegs.
An undersea menace has the merchants of Scalabar up in arms.
A strange sea monster is plaguing the trade ships near Scalabar, a coastal city. You have arrived in Scalabar at the behest of Sora Calhaigne. The lady of House Calhaigne needs brave heroes to investigate the loss of her galleon, the Morning Star. She has reason to believe that the sea monster is not what it seems.
Includes a list of random city encounters, a keyed map of the port city, Scalabar, as well as a simple overland map of the Scalabar coast, a map of a typical two-story warehouse, a keyed map of the pirate caves, and a keyed map of the ship Thresher.
I found a place that had a link to PDF version of the magazine that had this adventure.