The Launching of a Line

On this day in 1840, the British Cunard Steamship Lines launched the one-funnel, paddle-propelled, RMS Britannia, one of four steamers the company  

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intended to use in establishing the first regularly scheduled transatlantic passenger service. The ship's maiden voyage took place almost exactly five months later, on July 4, which happened to be Samuel Cunard's birthday, as well as the anniversary of American independence. The Britannia took 14 days and eight hours to cross the pond; a hundred years later, Cunard's three-funneled Queen Mary, would take 4 1/2 days.

Source:

Cunard Website