Tales of the Black Freighter

Tales of the Black Freighter is a fictional comic series within the graphic novel Watchmen. The comic was read in several issues (issue 3, 5, 8, 10 and 11) of Watchmen by an unnamed youth.
Plot
We only see one story from Tales of the Black Freighter, "Marooned". So, I'm going to talk about the plot of that. "The Sea Captain" and his ship was attacked by the Black Freighter. The Captain was the only survivor. Wanting to warn his hometown, he made a raft out of the bodies of his dead crew. When he got home, he believed the town was taken over by the crew of the Black Freighter. This caused him to kill several innocent people (including his wife, who he mistook for a pirate). Realizing what he did, he fled to the shore. There he discovered the truth: the Black Freighter had come him not the town. He swam out to sea and climbed on the ship.
Logic Behind The Story
Alan Moore and Dave Gibbons believed superheroes wouldn't be popular in the Watchmen universe. So, they chose to make it a pirate comic for it's "rich and dark" (Alan Moore) imagery. The comic was inspired by the Threepenny Opera song "Seeräuberjenny" (which translates to "Pirate Jenny"). The story is suppose to serve as a counterpoint to the world they created.
References:
http://en.wikipedia.org/wiki/Watchmen