No, HMS Pinafore did not turn into Pirates of Penzance. Both are separate operas created by the famous duo Gilbert and Sullivan. HMS Pinafore, also known as The Lass That Loved a Sailor, premiered in 1878, while Pirates of Penzance followed in 1879. Although they share the same creators and a similar comedic style, they have distinct plots, characters, and settings.
HMS Pinafore is set aboard a British naval ship and revolves around the romantic entanglements of the ship’s crew and their captain. On the other hand, Pirates of Penzance is set among a group of pirates and tells the story of a young pirate apprentice who is torn between his sense of duty and his desire to leave the pirate life behind.
Both operas are beloved for their witty lyrics, memorable tunes, and satirical take on societal norms, but they remain separate works in the Gilbert and Sullivan canon.