A series of letters of protest by the master of a Fratelli d’Amico Armatori tanker has provided new insight into an oil spill at a refinery in Peru.

The documents emerged nearly two weeks after the spill as the tanker began offloading the rest of its cargo of Brazilian crude in a ship-to-ship transfer.

The 158,000-dwt Mare Doricum (built 2009) has been at anchor off Lima since the 15 January spill, which saw some 6,000 barrels of oil leak from an underwater refinery pipeline after a wave from a massive volcanic eruption in Tonga impacted the unloading procedures.

The documents signed by Captain Giacomo Pisani emerged as officials in Peru mounted pressure on Repsol, the Spanish oil company that controls La Pampilla refinery. The letters were circulated to Peruvian media after high-level government officials, including environment minister Ruben Ramirez, boarded the Mare Doricum to interview the master.

In one letter of protest — which is the name of a form that a master fills out to document problems to protect the interests of their shipowners and managers — Pisani noted on the day of 15 January that a mooring master was not provided at La Pampilla’s Terminal 2.

In a handwritten note, a terminal representative responded that according to rules and the terminal manual, no mooring master was required at Terminal 2, and that a loading master was all that was needed.

Another of the documents signed by Pisani and published by Peruvian newspaper El Comercio reported that an “abnormal sea swell condition” occurred during discharge at the Repsol terminal.

The sea conditions were violent enough to part mooring ropes connecting the ship and the buoy.

Fratelli d’Amico has said the crew of the Mare Doricum first noticed an oil sheen at 5.25pm local time (2225 GMT) and quickly informed the chief officer, who immediately stopped all operations.

In another letter of protest written late on 15 January, Pisani stated that he asked for a local pilot to come on board at 5.30pm after the parting of the mooring ropes to help put the vessel in position. The pilot did not board until 11.05pm.

Repsol’s response

In a statement after the letters emerged, Repsol said providing pilots is not under its control.

Pisani penned another protest letter to Repsol when it seemed measures to control pollution were insufficient.

The Mare Doricum sits at anchor on 24 January off Peru’s coast. Photo: Scanpix

“As per terminal representatives’ advice, the pollution [that] occurred at CBM [conventional buoy mooring] Terminal 2 was under control of the terminal by their anti-pollution equipment, but it was observed that the oil boom was not of enough length to cover the entire length of the vessel all around,” he wrote.

Pisani fired off another missive the same day to document that the terminal did not carry out a diving operation to check the condition of the floating cargo hose that he said caused the oil spill.

Vessel snapshot

Name: Mare Doricum

Type: Crude tanker

Size: 158,319 dwt

Built: 2009

Owner: Fratelli d’Amico

Flag: Italy

Classification society: Rina

P&I insurer: Standard Club

Source: Equasis

A terminal representative responded by writing that an inspection took place the next day at between 3am and 4am local time, followed by a second inspection between 5.24am and 5.30am.

Repsol said in a statement that the underwater inspection could not take place immediately because of unsafe conditions, and a second diving team was sent with specialised equipment to handle the situation.

The next day, Pisani filed another letter of protest alluding to a dispute with the terminal representative. The master complained that the representative refused to sign another of letter of protest, in which Pisani rejected a letter of protest from Repsol.

He wrote that he rejected it because “the vessel didn’t move forward and never touched the marking buoy”. It is not clear what manoeuvre the terminal representative had protested.

On Friday, Fratelli d’Amico, the Italian shipping company that owns the Mare Doricum, said the ship remained at anchor while the investigation to determine the cause of the spill continued.

Tracking data from MarineTraffic shows International Seaways’ 74,200-dwt Seaways Samar (built 2011) is alongside the Mare Doricum.

Offloading is due to be completed on Friday, Fratelli d’Amico said.

“Fratelli d’Amico Armatori’s top priority remains to be the continued safe manning of the vessel and is fully cooperating with the authorities into the investigation,” the company said in a statement.