A tale of a tub. A cock-and-bull story; a rigmarole, nonsensical romance. The Tale of a Tub is a religious satire by Dean Swift.
Throw a tub to the whale. To create a diversion in order to avoid a real danger; to bamboozle or mislead an enemy. In whaling, when a ship is threatened by a whole school of whales, it is usual to throw a tub into the sea to divert their attention, and to make off as fast as possible.
A tub of naked children. Emblematical of St. Nicholas, in allusion to two boys murdered and placed in a pickling tub by a landlord, but raised to life again by this saint. (See Nicholas.) Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894