RMS Lusitania Sinking of the RMS Lusitania. RMS Lusitania RMS "Lusitania" was a British ocean liner and briefly the world's largest passenger ship. The ship was sunk on 7 May 1915 by a German U-boat off the southern coast of Ireland. The sinking presaged the United States declaration of war on Germany in 1917. The ship was a holder of the Blue Riband appellation for the fastest Atlantic crossing and was briefly the world's largest passenger ship until the completion of her sister ship . The Cunard Line launched "Lusitania" in 1906, at a time of fierce competition for the North Atlantic
Ship of the line War (1854–1856). She was decommissioned in 1874. The largest sailing three-decker ship of the line ever built in the West was the French "Valmy", launched in 1847. She had right sides, which increased significantly the space available for upper batteries, but reduced the stability of the ship; wooden stabilisers were added under the waterline to address the issue. "Valmy" was thought to be the largest sort of sailing ship possible, as larger dimensions made the manoeuvre of riggings impractical with mere manpower. She participated in the Crimean War, and after her return to France later housed the French Naval Academy