Rose's Big Mistake

The USS Genius was built from plywood and bent nails, and lots of blue paint. The blue paint was of the Crayola Washable variety, and naturally didn't last very long in the fish-infested oceans the ship was destined to sail. Or rather, destined to not sail.
The Genius was kept on land until Captain Anna Lowery of the International Novelist Committee for the Chocoholics (or INCC, as everybody in the universe called it) and Sidekick Rose Dougherty of the International Idiots Committee for Cupcake-lovers (or IICC, as everybody in the universe called it) boarded the ship that they had built together and slid it off the dock where it was resting. It was four hours before they remembered to untie the ship from the dock. By then, the blue paint had already started to peel off the plywood, and the non-watertight ship had begun to let drops of water through the sides.
Finally, the ship began to sail off towards the middle of the ocean, and Sidekick Dougherty let up all the flags, which were rectangular and had TARDISes painted on them.
(Rose had wanted to name the ship The Tardis, but Anna found The Genius to be more appropriate. Rose had offered the compromise of naming it The Geniuses, but Anna argued that there was only one genius on the two-crew ship.)
They sailed for a whole day before they noticed the water leaking through the very un-sturdy walls of the boat. It was Sidekick Dougherty who had first noticed the water in her cabin.
She lit a candle and walked through the ship to the Captain's Cabin, and knocked on the sheet that served as a door. She made no noise, hammering on the curtain, but she did succeed in lighting the sheet on fire, which served as a much better alarm clock anyway.
Captain Lowery dumped a bucket of water on the blazing fabric, and then shouted at the Sidekick for several minutes.
Finally, Rose managed to report what she had discovered about the water leak.
Anna frowned.
"I think you were hallucinating, Sidekick," she said. "Now go and get me another door. And put out that candle, before you drop it and burn the ship down."
Actually, if Rose dropped the candle, it would not burn the ship down. It would blow the ship up, because Rose had thought it necessary to hide several barrels of gunpowder and fireworks in the ship.
Rose blew out the candle and dropped it on the ground.
Unfortunately, the candle was a trick candle, similar to the ones put on birthday cakes, and after a second, it relit and blew the ship to smithereens. And nobody ever found out, because Rose and Anna were in the middle of the ocean, and nobody even noticed the explosion.

NOTE: Rose isn't really as stupid as I make her seem. She is more a fictional character with the name of my best friend. Sort of.