BAP Pacocha ( SS - 48 ) 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 , a " Balao " - class submarine with a GUPPY IA upgrade , she had been sold to Peru and commissioned on 28 May 1974 . At 18 : 50 in the evening of 26 August 1988 , " Pacocha " was transiting on the surface with the forward torpedo room and bridge hatches as well as the main induction valve open . Forty - nine men were aboard , including the Squadron Commander , to conduct an operational readiness inspection . About half an hour after sunset , ten minutes from " Pachocha " ’ s expected arrival at the port of Callao , the 412 ton Japanese fishing trawler " Kiowa Maru " ( also spelled " Kyowa Maru " and " Hyowa Maru " ) rammed her in the aft port quarter . " Kiowa Maru " was equipped with an ice - breaker bow , with a sub - surface protrusion designed to penetrate and break apart what it struck . " Pacocha " sank quickly . Four men died immediately in the collision and sinking : her commanding officer , " Capitán de Fragata " Daniel Nieva Rodríguez , died securing the bridge access hatch ; " Teniente Segundo " Luis Roca Sara and two enlisted men were trapped in flooded compartments and drowned . Twenty - three of her crew succeeded in abandoning ship . In the sinking submarine , " Teniente " Roger Cotrina Alvarado secured the watertight forward torpedo room door and attempted to pressurize the compartment . He then tried to secure the forward torpedo room hatch . Instead , however , he had to force the hatch open to free a sailor whose leg was caught in the hatch due to the 40 degree up angle the " Pacocha " assumed before sinking . As the " Pacocha " began to capsize water rushed into the compartment , washing lieutenant Cotrina down the ladder and fortunately , shortly afterwards , forcing the hatch door closed . Cotrina credited this sequence of events to a miracle , testifying , “ I saw a light and I experienced an ineffable power that allowed me to shut the hatch . ” There is little doubt that if that hatch had not been shut , no one inside the submarine would have survived . Two commissions , one conducted by the Peruvian military , the other by the Vatican came to the conclusion that with the water pressure , it would have been technically impossible for anyone to close the hatch . As such the Roman Catholic Church ' s Congregation for the Causes of the Saints authenticated the miracle . This is unusual , as normally miracles in the causes of saints , are those for cures believed by the Church to be through the saint ' s intercession , but in this case the declaration of a miracle was the obtaining of superhuman strength by someone in a disaster situation . On 6 June 2003 , Pope John Paul II celebrated Marija ' s beatification Mass ironically in the Croatian port city of Dubrovnik . Cotrina Alvarado received Holy Communion from the pope on this occasion , and afterwards gave him a small replica of the Pacocha as a memento . Less than five minutes after the collision , " Pachoca " settled on the bottom at a depth of with a 9 degree up angle . At 20 : 02 , with " Pachoca " an hour overdue , the Peruvian Navy declared an emergency . Boats were dispatched to search along " Pacocha " ’ s route . The tug " Jennifer II " was sent to rendezvous with " Kiowa Maru " and investigate . Some twenty minutes later , " Contralmirante " Guillermo Tirado , Commander of the Submarine Flotilla , arrived at the Callao Naval Base , assumed command , and dispatched the submarine BAP " Dos de Mayo " ( SS - 41 ) to search . At 20 : 30 , the survivors trapped in " Pacocha " released their messenger buoy and attempted to call aft compartments on the sound - powered telephone . There was no response . By 21 : 00 , the crew of " Jennifer II " had confirmed that " Kiowa Maru " had collided with something , and radioed their report to the base . While that report was in progress , the survivors in " Pacocha " fired a red distress flare . The Navy immediately issued a call for rescue and salvage divers to report for duty . Rescue of the survivors on the surface began at once , and within an hour and a half , twenty survivors and three bodies were drawn from the water . Three enlisted men had died of hypothermia during the four hours they had spent in the water . Meanwhile , 22 survivors mustered in " Pacocha " ’ s forward torpedo room : four officers , four chiefs , and fourteen junior enlisted personnel . The senior officer transpired to be Cotrina . At 21 : 20 they fired another flare that led searchers to the messenger buoy at 21 : 31 . Messenger buoys on " Balao " - class submarines do not have telephones , so communication could not be established , but those on the surface did realize that the buoy and flares probably meant that someone was still alive . The survivors held training in the use of the Steinke hood , with which most crewmen were unfamiliar . ( The Peruvian Navy , like the United States Navy , had stopped in - water escape training from depth several years previously . ) At 22 : 50 , the smell of chlorine gas in main control prompted another assessment of the boat ' s condition . A vent valve was found that had not been tightly shut , and more water had seeped into the aft battery compartment . All lithium hydroxide canisters were brought forward , and the survivors sealed themselves in the forward torpedo room . By 23 : 30 , two canisters of lithium hydroxide were opened and spread . The crew was put to bed . By midnight on Saturday , 27 August 1988 , all twenty survivors and three bodies had been brought ashore . Survivors were taken to the nearby Naval Hospital . Although all suffered from hypothermia , none had significant injuries . At the scene , an assortment of vessels were on the surface including the submarine , " Dos de Mayo " , a torpedo retriever , a floating crane , and several small craft . Locating divers during their off - duty hours was hampered by the lack of telephones in many of their homes , but by midnight , eight were at the scene in SCUBA gear . Depth to the deck of the ship was between aft and forward , with the ship variably reported as having between a nine and fifteen degree up - angle . The first team of divers followed the messenger buoy ' s line , which had played out to a significant distance . Since it was not located directly over " Pacocha " , a second line was tended straight down to the sail . The divers tapped on the hull and received a response from the forward compartment of the boat . However , they were unfamiliar with the code used , so were unable to interpret the tapping . At 00 : 40 , " Contralmirante " Tirado called Captain Schillingsburg , the United States Defense Attaché , to request rescue assistance from the United States Navy . By 01 : 00 the survivors had sent messages to the rescuers that they should be able to hold out for 48 hours . By 0200 , three volunteers in " Pacocha " had donned oxygen breathing apparatuses ( OBAs ) and walked through compartments as far aft as main control . The aft battery compartment had water over the deck , so it was not entered . Meanwhile , personnel ashore including several divers studied the salvage air connections on BAP " La Pedrera " ( SS - 49 ) ( the former , also a GUPPY IA " Balao " - class submarine ) and discovered that they did not have appropriate salvage air hoses or fittings . Ultimately , Mark V diving system umbilicals were used with fittings manufactured during the night on two frigates . ( Mark V diving hoses are negatively buoyant , ½ - inch inner diameter , 600 psig ( 4 . 2 MPa ) pressure rated hoses , MIL - H - 2815 . ) After two frustrating hours , improved communications with " Pacocha " were finally established at 02 : 27 using the signal ejector to pass written notes to the divers . Word was received at 0350 and passed to the survivors that the United States Navy was sending its rescue system . However , over the next few hours the estimated time of arrival of the rescue system shifted steadily later . Having had no communication from the surface for nearly two hours and unaware that there were currently no divers available , " Pacocha " fired another flare at 04 : 20 . Yellow was picked so as not to give the impression that something new was seriously wrong — they only wanted to express concern that they had not heard anything in a couple of hours . However , at 04 : 40 a small electrical short and fire broke out in main control . It was brief and self - extinguishing , but renewed concern for the survivors ' atmosphere . Only carbon dioxide extinguishers were available for fire - fighting . A new group of divers arrived on scene at about 05 : 00 after reviewing salvage connections , escape trunk configuration , and other details on " La Pedrera " . Shortly after the divers went to work , they recovered the body of " Pacocha " ’ s Commanding Officer , " Capitán de Fragata " Nieva , just inside the deck access door to the sail . At 06 : 00 the survivors held reveille and prepared breakfast . Utilizing the signal ejector , communication was passed that the crew was in good spirits with enough air to last for seventy - eight hours based on calculations of available oxygen and lithium hydroxide . They also had adequate supplies of water , but no food after eating what little they had , including cake , for breakfast . While inspecting the submarine , the survivors noted a heavy black cloud rising from below the deck in the forward battery compartment . No one entered this compartment again . Two more canisters of lithium hydroxide were opened and spread on the upper bunks . Later in the morning another four canisters were opened . Approximately twenty canisters were unopened . One eight cubic foot ( 230 L ) oxygen cylinder was bled into the compartment ; three oxygen cylinders were left unused . Information on the use of the escape trunk and the Steinke hood was passed from the surface . The crew was divided into five groups and one member from each group trained in the operation of the escape trunk . Groups were arranged by seniority , with one officer in four of the five groups , and by other factors such as swimming ability and self - confidence . Via message , " Pacocha " informed those on the surface that there were twenty - two survivors . At 07 : 30 a message was sent to " Pacocha " informing them that the fly - away rescue system was on the way from the United States . This provided a visible boost to morale among the crewmen , and all involved in the casualty planned to wait for that equipment . However , by 09 : 50 , the crew was becoming listless , agitated , and hyperventilating . The boat ' s only atmosphere monitoring equipment was aft in the flooded compartments , but the lithium hydroxide did not seem to be working as well as expected . Cotrina was becoming concerned about the submarine ' s atmosphere . He spread four additional lithium hydroxide canisters . To exacerbate the situation , their only light , the emergency light located at the bottom of the forward ladder , was periodically flickering on and off , and the beam from their only battle lantern was steadily growing weaker . Cotrina passed a message to the surface requesting guidance . " Contralmirante " Tirado instructed Cotrina to use his best judgment in decided when to escape . Cotrina consulted his crew ; their recommendations to escape were unanimous with one exception . " Teniente " Lindley offered various reasons to wait , and if he had to escape , he wanted the divers to provide SCUBA tanks since he had been trained in their use . Cotrina ordered him to join the first group of escapees . At 11 : 30 , divers completed connecting high and low salvage using Mark V diving umbilicals for hoses and the manufactured fittings . The high salvage was connected to air banks on the submarine BAP " Abtao " ( SS - 42 ) , named after the Battle of Abtao . These banks were charged by thirty - five - year - old , oil - lubricated compressors . There are no filters on the system , and air samples of the air banks had never been taken . During escape training , crew members decided to inflate their Steinke hood s in the compartment before entering the escape trunk , and to use them as flotation devices , but not to enclose their heads in the hoods . One member of the first group , Chief Monzon , did wear the hood . He was to be the third most seriously injured of the twenty - two escapees . After inflating the escape devices , four men entered the escape trunk and controlled flooding and pressurizing from inside the trunk . After the side access hatch was opened , the four men spent at least ten minutes arguing over who would exit first . Finally " Teniente " Gomez , the senior man , ducked under and began his ascent , followed in turn by Chief Monzon and Petty Officer Reyes . All three men reached the surface and were promptly rescued . However , within minutes of reaching the surface , they began suffering great pain in their joints , became disoriented and unsteady , experienced shortness of breath , and displayed symptoms of crepitus . The rescuers on the surface had been told to expect four men in the first group . Finding only three , they began to search for the missing " Teniente " Lindley . While they searched , the survivors drained and opened the escape trunk , where they found the " teniente " , alive and well , still in the escape trunk . Lindley reentered the submarine , and was added to the last escape group . The second group , led by " Teniente " Augusto Ivan Aranguren Nieri , completed their escape by 12 : 25 without incident , and were flown by helicopter to the recompression chamber . The helicopter flew low over the water , to keep the air pressure as high as possible . Immediately after the second group surfaced , air was supplied through the high salvage connection . When the connection was opened aboard " Pacocha " , high - pressure seawater came from the line since it had not yet been blown dry . The survivors immediately shut the high salvage connection valve and never reopened it . The low salvage line was open to atmosphere on the surface , not pressurized , but was connected to the submarine below the level of water in the bilge . Thus , that line was filled with seawater to a depth equivalent to the pressure in the boat , and did not allow air flow . All five of the survivors in the third escape group completed an uneventful escape by 12 : 40 . However , after they left , the outer escape hatch could not be shut from inside the submarine , so when the crew attempted to drain the trunk , seawater continued to flood into the submarine until the valves were secured . After the problem was communicated to the surface , divers investigated , discovered that the hatch ’ s dogs were obstructing closure , and freed the obstruction with a large wrench . The fourth escape group made an uneventful escape by 15 : 15 . On reaching the surface at least one of them was transported to the shore recompression facility by helicopter . The fifth group then made an uneventful escape by 16 : 25 . By this time , a recompression chamber was on scene on the floating crane along with two medical officers . All three in this escape group were recompressed within five minutes of surfacing . After the fifth group left the escape trunk , divers placed a set of SCUBA bottles in the trunk . The final three escapees spent between one - half and one hour breathing from the SCUBA bottles before escaping at 18 : 05 , by which time personnel topside were again becoming apprehensive . Divers were sent to investigate the delay and were present when all three escapees simultaneously emerged from the escape trunk . Since the chamber at the scene was occupied , these individuals were transported by boat to the shore facility . About an hour and a half lapsed between surfacing and recompression , apparently because no chamber was available . " Oficial de Mar 2o . " Carlos Grande Rengifo developed such severe decompression sickness ( the " bends " ) , possibly combined with gas embolus , that he died during recompression treatment . The Peruvian Navy ' s efforts to salvage " Pacocha " began on 30 August 1988 , immediately after the crew escaped , and continued for eleven months . One hundred fifty men , seventy of them divers from the Salvage Service , worked eight hundred hours , two hundred of preliminary inspection and six hundred diving . The submarine broke the surface again on 23 July 1989 , eleven months after she was sunk . After being studied for the effects of the ramming and sinking , her hulk was cannibalized for spare parts for other Peruvian submarines .