RV Petrel, or R/V Petrel (IMO: 9268629, MMSI: 235102789), is a research vessel sailing under the UK flag and owned by the United States Navy and once owned by Microsoft co-founder Paul Allen. The ship is named after the petrel, a sea bird. The ship was completed by Brattvaag Skipsverft, Norway in 2003 as the deepwater offshore inspection vessel Seaway Petrel for service with Stolt Offshore. She was later renamed Acergy Petrel, then Seven Petrel with Subsea 7.,
In 2016, the ship was purchased by Allen, renamed Petrel and converted for deep-submergence research and archeology. Over two dozen wrecks were explored and recorded between 2017 and 2020, when the ship was laid up. In October 2022, she was purchased by the United States Navy's Naval Facilities Engineering Systems Command, for operation under Oceaneering International management. In 2025, it was renamed MV Sarah Lynn. * Petrel (2016-2025)
Paul Allen's explorations Prior to 2020, the primary mission of the ship, which was fully funded by Allen's estate, was to explore historically significant wrecks at challenging depths and conditions. A precondition set by Allen was for discovered wrecks to be respected as war graves and their locations kept secret, known to only national governments and museums. In the PBS documentary USS Indianapolis Live from the Deep, Allen said, "We've done a number of these explorations to try to find sunken warships. We try to do these both as really exciting examples of underwater archaeology and as tributes to the brave men [who] went down on these ships". Petrels other mission profile included hosting scientific projects under Allen's mother company, Vulcan Inc.
Petrel explorations were coordinated with organizations around the world. For United States Navy wrecks, the team collaborated with the Naval History and Heritage Command. In the Philippines, the crew worked with the National Museum and the Battle of Surigao Strait Memorial Council. In 2018, Petrel worked with Australian National Maritime Museum to explore . Robert Kraft, who served as subsea director for Allen, and Paul Mayer, Petrels lead researcher, traveled to Japan to hand over ROV video of Imperial Japanese Navy wrecks to the Yamato Museum.
The project crew was aboard Allen's operating the megayacht's crewed-submersible Pagoo, Argus 3000 remotely operated vehicle (ROV) and Bluefin 12D autonomous underwater vehicle (AUV). The 20 civilian marine crew and 10 project crew worked on 12-hour shifts aboard Petrel. The project crew consisted of Kraft the expedition leader, Mayer as lead researcher, four ROV pilots and technicians, one AUV specialist, one multibeam surveyor, one videographer, and one systems support engineer. For each expedition, local historians, scientists, and observers complemented the project crew.
Crew expeditions in 2015 aboard Octopus Ironbottom Sound expedition The team, while on board Octopus, mapped of Ironbottom Sound in January 2015, identified 29 wreck locations, seven wreck debris fields, and several possible plane locations. Of the 29 wrecks located, six were positively identified and confirmed to be the heavy cruisers , , , , and , and the light cruiser . Eleven wrecks were "tentatively" identified to be the Japanese destroyers , and , and the American destroyers , , , , , , , and . The identification using the sonar imagery with vessel measurements and historical records is pending confirmation by ROV exploration. The remaining 12 wreck locations were not identified during the expedition and require further study.
Musashi After several years of searching, the same team discovered the in March 2015.
HMS Hood bell recovery In August 2015, the team recovered the bell of after obtaining license from the UK Ministry of Defence. The recovery of the bell was performed upon the request of the HMS Hood Association. Only three of HMS Hoods crew survived and it was the wish of one of them to recover ship's bell as a memorial to shipmates. The bell from HMS Hood was unveiled by the Princess Royal on 24 May 2016 to mark the 75th anniversary of the Royal Navy's largest loss of life (1,415 sailors) from a single vessel.
Malta wreck mapping
While on board Octopus, the project crew deployed a Bluefin 12D AUV and mapped of seabed around Malta in September 2015. Sonar images of shipwrecks, several aircraft, torpedoes, and debris field were captured by the AUV.
Ship details
Following the Musashi discovery and the Hood expedition in 2015, Allen bought Petrel in 2016, refitting her as a dedicated research and exploration platform.
Petrel expeditions in 2017 Artigliere Petrel found the Italian Regia Marina World War II destroyer in March 2017.
USS Indianapolis Petrel found in August 2017. Indianapolis was located on 19 August 2017 at a depth of in the Philippine Sea. The discovery introduced Petrel as Paul Allen's newest addition to his expedition fleet. Kraft said of the elusive Indianapolis, "We did 18 search grids, each one is about a 120 square kilometers and that took us the course of a couple of months. It was about 26 days of searching".
The Indianapolis wreck is upright with her hull and armaments intact and well preserved in the depth. Her bow number 35 was seen by the ROV. Rusticles or oxidized wrought iron were found emerging from one of the main guns of the ship by the crew.
Surigao Strait After discovering USS Indianapolis, Petrel sailed to Surigao City in October 2017 to participate in the 73rd commemoration of the Battle of Surigao Strait. In November 2017, after gaining approval from the Philippines' National Museum, Petrel surveyed Surigao Strait and discovered the wrecks of the Japanese battleships , , and the destroyers , , and . Each one was investigated by the ship's ROV and an onboard local historian confirmed the identity of the wreck.
Ormoc Bay and USS Ward In December 2017, Petrel explored Ormoc Bay and discovered the wrecks of the American destroyers , , the , and what is believed to be two s. The discovery of the wreck of USS Ward was a central theme for the 76th commemoration of the Attack on Pearl Harbor on 7 December.
Petrel expeditions in 2018 Return to Ormoc Bay In early January 2018, Petrel returned to Ormoc Bay and dived one of the Yūgumo-class destroyers found in 2017. Based on the guns and armament configuration, she was identified to be . The identification also validated the final resting places of the other ships of the lost Japanese convoy TA-4: the destroyers , and . The convoy was attacked by aircraft from Task Force 38 in the Battle of Ormoc Bay. Petrel and Octopus also dove their crewed submersible Pagoo on USS Cooper.
C-2A Greyhound in the Philippine Sea In February 2018, Petrel, with a US Navy team aboard, located and mapped the wreckage of a Grumman C-2 Greyhound aircraft that crashed into the Philippine Sea en route to on 22 November 2017.
USS Lexington in the Coral Sea On 4 March 2018, Petrel explored the Coral Sea and discovered the wreck of the aircraft carrier , which sank during the Battle of the Coral Sea.
USS Juneau On 17 March 2018, Petrel located the wreck of the antiaircraft light cruiser . Juneau was sunk by the in the aftermath of the first Naval Battle of Guadalcanal, sinking with the loss of 687 men, which included the five Sullivan brothers.
USS Helena On 11 April 2018, Petrel located the wreck of the light cruiser . Helena was sunk during the Battle of Kula Gulf in 1943 by three torpedoes fired from a Japanese destroyer with a loss of 168 of her crew.
HMAS AE1 The Royal Australian Navy's submarine , which was lost at sea with all hands on 14 September 1914, and only discovered in December 2017 on the seafloor off the Duke of York Islands in Papua New Guinea (PNG), was visited by Petrels ROV. Petrels crew devised a close-up camera to view details inside the torpedo tube and engine telegraph. This exploration published on 23 April 2018, was supervised by Find AE1 Ltd in partnership with the Australian National Maritime Museum, the Royal Australian Navy, Curtin University, the Western Australian Museum, and the Submarine Institute of Australia. The approval for the survey was granted by Papua New Guinea National Museum and Art Gallery.
Petrel expeditions in 2019 Niizuki Petrel found the wreck of the upright in of water in January 2019. While the wreck was heavily damaged, her mast is still attached and complete. The find of Niizuki was noteworthy because she was credited for sinking with the longest torpedo shot ever, with estimates ranging from . Niizukis discovery is also noteworthy as the photos of the wreck are the first photos of the ship to exist; no photos of her in service are known to have been taken.
Jintsū In February 2019, the 's wreckage was discovered by Petrel near the mouth of Kula Gulf in the Solomon Islands. The broken cruiser rests in of water. Her bow section is lying on its port side and the stern section is upright.
Hiei On 6 February 2019, the discovery of the was announced, the first Japanese battleship sunk in World War II. According to Petrel, Hiei now lies upside down in of water northwest of Savo Island in the Solomon Islands. Hiei is the fourth Japanese battleship found by Petrels crew. The was found in March 2015, and the s and were found in November 2017. Petrel was also able to survey another , , in a separate mission. Lead researcher Paul Mayer said that Hiei lies away from Kirishima.
USS Hornet On 12 February 2019, the crew announced they had located the wreck of the aircraft carrier at a depth of more than off the Solomon Islands. She is in remarkably good condition. She sits right-side up with her island still in place. A portion of her flight deck has collapsed due to the fire that raged on her decks during the battle. A portion of her stern is torn away, but the hull remains mostly intact. Several aircraft are scattered among the wreck.
USS Strong On 26 February 2019, the crew announced they had located the wreck of the destroyer , resting at a depth of . She rests in pieces, the largest of which is the heavily damaged forward section of the ship lying on its port side. The rest of the ship was largely fragmented by the detonation of her depth charges and lies in a compact debris field that includes the ship's boilers, propellers, and wheelhouse.
USS Wasp On 13 March 2019, the crew announced they had located the wreck of the aircraft carrier, resting at a depth of . The ship sits upright, though appears to have broken in two places, just forward and just aft of the island, apparently on impact with the seabed. The island itself is still in place, though the funnel structure was ripped off during the sinking. Several aircraft were also found in the debris field, including Dauntlesses and Avengers.
Furutaka On 4 May 2019, the crew announced they had located the wreck of the Japanese heavy cruiser at a depth of . She lies in two sections, with the bow sitting near the main part of the wreck, which is upright and the bridge is about away.
Maya On 1 July 2019, it was announced that the wreck of the had been found off the coast of the Philippine island of Palawan. She is mostly intact, with the exception of her forward bow, which broke off and is lying upside down just astern of the rest of the ship. Her bridge and guns are also intact. She lies in of water.
Mogami On 9 September 2019, it was announced that the wreck of the had been found in the Bohol Sea. She lies mostly intact, with the exception of her bow, which has been blown off, but lying nearby. She sits straight side up at a depth of .
USS St. Lo