On January 29th, 1863 the British blockade runner Princess Royal was pursued by USS Unadilla and run aground while trying to enter the harbor at Charleston, SC.
Her cargo included arms and ammunition as well as an unrecorded number of large rifled naval guns and two powerful steam engines slated to be installed in Southern ironclads then under construction.
These imports were of such great potential value to the South that they have been called "the war's most important single cargo of contraband."
In thick, predawn haze on January 31, 1863, CSS Chicora and CSS Palmetto State raided the Federal blockading force of unarmored ships lying just outside the entrance to Charleston Harbor.
Their goal was to drive the blockading vessels away from the Princess Royal and recover her cargo.
–Description from the publisher