In the last years of Gunsmoke, Festus was turned into a character that was a buffoon. What was once a tough hardcore cowboy became the town clown, singing and whistling to himself as he went to the saloon to tell the other characters stories that emphasized how ignorant he was.
Another trend was to find bizarre characters and make them the star of any given episode. I guess they gave up on the traditional Western? Captain Sligo is like some kind of legendary sea-faring character who comes from a life as a whaling captain. Sligo decides to live on a farm that is supposed to be his land-ship, with a mast in the front yard, and other ship knick-knacks around his home. He is always shouting lots of annoying remarks about life on the sea to his first mate, played by Royal Dano. Like usual, Dano plays his character like some kind of a half-wit.
Richard Basehart works a thick Irish accent. He also spends most of the episode trying to seduce a lonely neighbor widow by berating her character, and otherwise verbally abusing her into loving him, as often happened on Gunsmoke. Men who were crude, obnoxious, and stupid were often shown to be a real catch for the frontier women of Kansas, back in the days of Gunsmoke.
In spite of many of the townies hating Sligo, he punches his way to earning the love and respect of his neighbors. Like all guest characters who become good friends with Dillon, Festus, Miss Kitty, and Doc Adams, he is never seen again on Gunsmoke.