The Loss of MV Berge Istra: An Ore-Bulk-Oil Carrier Vanished in the Western Pacific, 29 to 30 December 1975

Sometime on or about Tuesday 29 to 30 December 1975, in the western Pacific Ocean approximately southeast of Mindanao, the ore-bulk-oil carrier MV Berge Istra sent her last position report. She was Liberian-flagged, Norwegian-owned by Sig. Bergesen d.y. of Bergen, 227,550 dwt at the time one of the largest cargo ships in the world, and only three years out of the Uljanik shipyard at Pula in Yugoslavia. She was sailing from Tubarão in Espírito Santo, Brazil, to Kimitsu, Japan, loaded with iron ore, with a crew of 32. No SOS was transmitted. The ship was reported missing on 7 January 1976. A multinational search of the western Pacific located nothing identifiable, and was called off on 16 January 1976.

Nineteen days after the disappearance, on 18 January 1976, the Japanese fishing vessel Hachi-O-Maru 6 picked up two crew members alive from a small improvised raft. They were the only survivors: Imeldo Barreto León, aged 41, of Punta del Hidalgo in Tenerife, and Epifanio Perdomo López, aged 38 or 39, of Taganana in Tenerife. Both were Canarian able seamen. They reported two large explosions amidships in quick succession and a sinking within approximately four minutes.

No wreckage of Berge Istra has ever been recovered. Fifty years on, the precise cause has never been judicially established. The question this article addresses is what destroyed her between her last report and the moment her raft drifted within sight of a Japanese fishing boat: a question the Liberian flag-state inquiry answered behind closed doors, in summary form, and that the maritime safety literature has spent the half-century since trying to make sit alongside the loss of her sister and the wider record of the OBO class.

The ship and the OBO class

Berge Istra was an ore-bulk-oil carrier, an “OBO” of a class designed to carry crude oil in some tanks or dry bulk (iron ore, grain) in the same holds on different voyages. Her length overall was about 314 to 315 metres, her beam about 50 metres, her deadweight approximately 227,550 tonnes and her gross tonnage approximately 115,441. She flew the Liberian flag of convenience, a fact that matters here because the formal inquiry into her loss was therefore Liberian, not Norwegian.

Her owner of record was Sig. Bergesen d.y. of Bergen, with joint-ownership entries including Skibs A/S Snefonn, Skips A/S Bergehus, A/S Sigmalm and General Ore International Corp. Her IMO number is 7123540. She was built in 1972 at the Uljanik shipyard at Pula, then in the SFR Yugoslavia and now in Croatia, as the yard’s hull number 296. At launch she was one of the largest cargo ships in the world.

The OBO class itself was a 1960s innovation that peaked commercially in the early 1970s and, by the mid-1980s, had been substantially abandoned because of high maintenance costs and a disturbing safety record. The class is associated with a cluster of unexplained losses the maritime safety literature now treats as the “OBO problem”. Berge Istra (1975), her sister Berge Vanga (1979) and MV Derbyshire (1980) are the three most-cited cases.

The voyage

Berge Istra loaded a cargo of iron ore at Tubarão (Vitória), in Espírito Santo, Brazil, in the second half of December 1975. Public sources give the loaded cargo tonnage in figures ranging from approximately 188,000 tonnes to approximately 211,000 tonnes; the exact loaded tonnage at Tubarão is not in the public record consulted for this article.

She departed Tubarão on or about 22 December 1975, on the figure given by marinacivil.com of “eight days before the explosion”. The route was Brazil to East Asia via the Cape of Good Hope and the Indian Ocean, a standard 35 to 40 day passage for an ore carrier of her size on the Tubarão-to-East-Asia run, with the Suez Canal not a practical alternative for a 227,550 dwt OBO. Spanish-language sources, Diario de Avisos and marinacivil.com, identify the destination specifically as Kimitsu, Japan, a major iron and steel port in Tokyo Bay; some other summaries say “to Japan” without further specification.

The disappearance

Berge Istra’s last communication came on 30 December 1975 in most sources. The Pomorstvo.info Croatian account dates the last contact 29 December 1975; the safest published phrasing is “on or about 29 to 30 December 1975”. The position lay southeast of Mindanao, in the western Pacific, given in different sources as approximately 550 miles or 1,000 miles distant from that landmark. No primary source consulted gives precise coordinates for the last reported position.

No SOS was transmitted. No wreckage was located in the immediate or extended search. The ship was reported missing on 7 January 1976. A multinational search operation, drawing in vessels and aircraft from Japan, the United States and the Philippines, was conducted across the western Pacific southeast of Mindanao and located nothing identifiable. The search was called off on 16 January 1976. Lloyd’s of London declared Berge Istra lost on or about 19 January 1976.

The rescue, 18 January 1976

On 18 January 1976, two crew members were picked up alive from a small raft in the western Pacific by the Japanese fishing vessel Hachi-O-Maru 6. They had been adrift for approximately twenty days. Spanish sources locate the rescue “northeast of Australia, approximately 500 miles from the wreck site”; no primary source consulted gives precise coordinates.

The survivors were Imeldo Barreto León, aged 41, of Punta del Hidalgo, Tenerife, and Epifanio Perdomo López, aged 38 or 39, of Taganana, Tenerife. Both were Spanish able seamen. By their own contemporaneous account, they had been off-watch and were socialising near the bow when the ship was destroyed. Both were thrown into the water by the explosion. Barreto reached an improvised raft first and saw Perdomo floating face-down with a serious head wound bleeding heavily. Barreto pulled him onto the raft and revived him with mouth-to-mouth resuscitation. They survived twenty days on the raft on small water rations and what they had managed to grab.

After rescue, they were transferred to a US military base and then by helicopter to a hospital in Okinawa. In early March 1976 they returned to Tenerife, where they were met by a large crowd at Los Rodeos airport. A British Pathé newsreel from 1976, archived at britishpathe.com (asset 203094), records the two survivors in Japan recounting their ordeal. It is a contemporaneous primary source.

The Liberian flag-state inquiry

The formal inquiry into the loss was held by Liberia, the flag state, behind closed doors. Its full findings were not published. The Liberian Deputy Commissioner F. T. Liniger oversaw the inquiry. Norwegian authorities participated as an interested party through the owner’s nationality, but the controlling inquiry was Liberian. The public summary found no evidence of collision, piracy, or external attack, and concluded that the most probable cause was an internal explosion of hydrocarbon vapours in the cargo system.

The most commonly cited mechanism, set out by the retired Bergesen captain Johnny Eilers in a 2011 Dagbladet interview reproduced on Wikipedia, runs as follows. The wing tanks, used for crude oil on outbound voyages, were not properly cleaned of hydrocarbon residue before iron-ore loading at Tubarão, and the inert-gas system intended to prevent ignition was unreliable in heavy seas, with the deck water seal allowing vapour to leak back toward the generator. Japan required inerted wing tanks on arrival, so the generator was typically started en route east. Starting it in this state would, in Eilers’s words, cause “the whole deck to open up”, matching the survivors’ account. This is the leading mechanism in the published literature. It is not a court-of-inquiry finding of fact specific to Berge Istra, because no wreckage was recoverable.

Aftermath and the sister Berge Vanga, 1979

On 27 to 29 October 1979 (sources differ), the sister OBO MV Berge Vanga, also Uljanik-built (1974), Bergesen-owned and Liberian-flagged, disappeared in the South Atlantic on the same Brazil-to-Japan iron-ore trade. Forty crew were lost, no survivors found, and debris consistent with the tanker recovered northwest of Tristan da Cunha. The leading hypothesis was again internal explosions from hydrocarbon residue.

No wreckage of either ship has ever been recovered. No source consulted supports any 2024 sonar discovery of the Berge Istra wreck.

The OBO problem in the maritime safety literature

The ore-bulk-oil carrier was a 1960s innovation, designed to switch between crude oil and dry bulk on alternating voyages and so cut the empty backhauls that ordinary tankers and bulkers ran. The class peaked commercially in the early 1970s. Berge Istra was launched at that peak, three years before her loss, when the OBO was still the maximally efficient large-tonnage cargo design on paper.

By the mid-1980s the class had been substantially abandoned. Marine Insight’s retrospective “OBO Vessels: Rise and Fall” attributes the retreat to two factors: high maintenance costs, driven by the tank-cleaning regime that a cargo changeover imposed, and a safety record that was no longer defensible. The Wikipedia OBO entry, drawing on the same body of safety literature, records 151 OBO losses in the period 1980 to 1987, a casualty rate the class never recovered from commercially.

Berge Istra sits at the head of the loss cluster the literature now references. Berge Istra (1975), MV Anita (1973), Berge Vanga (1979) and MV Derbyshire (1980) are the four cases the cluster is built around. The post-1980 response, led by the International Maritime Organization and the classification society Det Norske Veritas, focused on three things: inert-gas system reliability on combination carriers, tank-cleaning protocols on cargo changeovers, and a structural reassessment of large bulk carriers. That work culminated in the 1997 amendments to SOLAS Chapter XII, the bulk-carrier-safety chapter that remains in force.

Det Norske Veritas, the Norwegian classification society that had classed Berge Istra, played a central role in that reassessment, holding the structural and inert-gas certification record for the ship and a substantial share of the wider OBO fleet. The Bergesen d.y. fleet alone lost both Berge Istra and Berge Vanga in the second half of the 1970s, two ships from one owner on the same trade, in conditions for which the leading hypothesis was the same. The maritime safety literature treats the period from the loss of Berge Istra to the 1997 SOLAS amendments as a single arc in the regulation of combination carriers, and Berge Istra as the opening case.

Evidence

The survivors’ contemporaneous accounts to Japanese maritime authorities on 18 January 1976, to Norwegian authorities and Bergesen d.y. shortly afterwards, and to the international press while still in Japan (testimonial).
The British Pathé 1976 newsreel, asset 203094, recording the two survivors in Japan recounting their ordeal (testimonial).
Retrospective accounts in the Spanish press 2014, 2016 and 2024, and the JMR Universidad de Cantabria 2024 review article, restating the survivors’ account and the published reconstruction (testimonial).
The Liberian flag-state inquiry record, held behind closed doors under Deputy Commissioner F. T. Liniger, with a closed-summary cause finding of internal hydrocarbon-vapour explosion; the full file is not directly published (official-record).
Bergesen d.y. company voyage and certificate records, partially published in Dagbladet (Astrid Meland, 3 January 2006; Johnny Eilers interview, January 2011) (official-record).
Det Norske Veritas classification society OBO-class records, and contemporaneous Norwegian press coverage in Norges Sjøfartstidende, Bergens Tidende, Aftenposten and Dagbladet, January to February 1976 (official-record and testimonial via press).
The survivors’ improvised life raft, retained and used in the 2014 documentary Los náufragos del Berge Istra directed by Víctor Calero (physical).
The IMO 7123540 ship registry entry and Uljanik yard records, including hull number 296 (physical).

No physical wreckage of Berge Istra has ever been recovered. No bodies were recovered other than the two survivors.

Hypotheses

A. Hydrocarbon-vapour explosion from inadequately cleaned wing tanks, the leading reading. For: the survivors’ two-explosion account; the Eilers Dagbladet 2011 mechanism in detail; consistency with the loss of Berge Vanga in similar conditions; consistency with the broader OBO inert-gas reliability problem in the 1970s; the attributed Liberian inquiry conclusion. Against: no physical evidence; no court of inquiry of fact made this finding because no wreckage was recoverable; the mechanism is reconstructed from testimony and general industry knowledge, not from instrumented evidence.

B. Iron-ore cargo shift in heavy weather causing structural failure. For: cargo shift is a known failure mode for bulk carriers in heavy weather. Against: period weather reports for the area on 29 to 30 December 1975 do not record severe weather sufficient to shift a properly trimmed iron-ore cargo, the survivors heard explosions rather than the prolonged structural noise of a failing hull, and the ship sank in approximately four minutes by the survivors’ account, faster than typical cargo-shift failures.

C. Fatigue or structural failure of OBO hull design, the “OBO problem” cluster. For: Berge Vanga (1979), MV Derbyshire (1980) and 151 OBO losses 1980 to 1987 form a cluster the safety literature treats as a structural problem. Against: the survivors describe explosions, not progressive structural failure; Derbyshire and most documented OBO losses involve progressive flooding and slower foundering, not a four-minute sinking.

D. Collision with a submerged object or another vessel. For: no specific evidence; included for completeness. Against: no vessel was reported missing or damaged in the area; no obstruction is plotted in the open ocean at that depth and position; the survivor account describes internal explosion, not external impact.

E. Sabotage, piracy or external attack. For: no evidence. Against: no claim of responsibility, no political motive on the Bergesen fleet, no piracy active on this route at that scale in 1975, and the Liberian inquiry explicitly rejected external causes.

F. Combination: hydrocarbon-vapour ignition triggered by or coinciding with structural movement. For: combination hypotheses tend to fit ambiguous loss cases because they explain both the suddenness of the failure and the lack of recoverable evidence. Against: combination hypotheses are unfalsifiable in the absence of a wreck and tend to obscure the dominant mechanism.

What remains unknown

No physical wreckage of Berge Istra has ever been recovered. The name of the master on her final voyage is not in the public record consulted. Neither is the full crew manifest by nationality, nor the names of any senior officers. The exact loaded cargo tonnage at Tubarão is not published. The Liberian flag-state inquiry file in full is not public. Whether a separate Norwegian Sjøfartsdirektoratet file exists, and what it concluded, is unverified. The exact spelling and Japanese registration of Hachi-O-Maru 6 is not confirmed against a primary record. The exact coordinates of the last reported position and of the rescue are not in the sources consulted. Fifty years on, what destroyed Berge Istra has never been judicially established.

Sources

Primary, contemporaneous and retrospective documentary

British Pathé newsreel (1976), asset 203094: britishpathe.com/asset/203094/
BERGE ISTRA, IMO 7123540, ship registry: balticshipping.com/vessel/imo/7123540
Diario de Avisos, “Historia de un milagro” (2014): diariodeavisos.com/2014/01/historia-milagro/
Diario de Avisos, “40 años de la tragedia del Berge Istra” (2016): diariodeavisos.com/2016/01/40-anos-tragedia-del-berge-istra/
Diario de Avisos / El Español, “La increíble historia de los dos náufragos canarios” (2024).
Asociación Española de Marina Civil, “Perdidos en el Pacífico”: marinacivil.com.
JMR Universidad de Cantabria, “A Review of the MS Berge Istra Accident” (2024): jmr.unican.es.
Los náufragos del Berge Istra, documentary directed by Víctor Calero (2014), made using the survivors’ actual raft and containing extended survivor interviews (IMDb tt4592518).
Tamaimos, “Proyección de ‘Los náufragos del Berge Istra’ en el 40 aniversario de la tragedia” (2016): tamaimos.com.

Secondary, current

Wikipedia, “MS Berge Istra”, “MS Berge Vanga”, “Ore-bulk-oil carrier”.
Pomorstvo.info, “Berge Istra: Slava i tragedija”: pomorstvo.info.
Marine Insight, “OBO Vessels: Rise and Fall”: marineinsight.com.