BAP Pacocha (SS-48) was a submarine of the Marina de Guerra Peruana (Peruvian Navy) named for the 1877 Battle of Pacocha, in which the Peruvian ironclad Huascar clashed with the Royal Navy. Formerly USS Atule (SS-403), a Balao-class submarine with a GUPPY IA upgrade, she had been sold to Peru and commissioned on 28 May 1974. Less than five minutes after the collision, Pachoca settled on the bottom at a depth of with a 9 degree up angle. At 00:40, Contralmirante Tirado called Captain Schillingsburg, the United States Defense Attaché, to request rescue assistance from the United States Navy.