RMS Lusitania was torpedoed by U-20 on 7 May 1915 off Old Head of Kinsale, Ireland, killing 1,198 passengers and crew. The ship's manifest acknowledged rifle ammunition. A second explosion shortly after the torpedo strike has fuelled debate over whether undisclosed munitions or a boiler failure caused it. Naval historian Patrick Beesly's research suggests Admiralty signals intelligence placed U-20 in the area but no protective escort was dispatched. The claim that Winston Churchill and the Admiralty deliberately withheld protection to provoke US entry into the war is partly coherent at the level of negligence; the stronger claim of deliberate sacrifice has no documentary proof.