Reubenson and Martin Fugui have been boating around their island village their entire lives, but they'd never seen anything like this before.
The cousins were on their usual morning boat run on Saturday to get supplies from a local market when they spotted it.
"It was an object floating [in the water]," Reubenson told the ABC from his village, Fourau, in Solomon Islands' Malaita province.
"We were scared at first, because we'd never seen a vessel [like this] in our lives."
Isolated and in deep water, they were hesitant at first to board the "strange-looking" boat and waited for half an hour for any sign of life before they were convinced it was safe.
As they got closer, they saw its engines were missing, and Reubenson, the older of the two, told Martin to climb aboard to find out what was inside.
"There was a single cabin and it still had its steering wheel," Martin said.
Other than that, the engines were gone and it was just filled with empty plastic water bottles.
The cousins towed the strange 17m-long vessel back to their village.
Later, on closer inspection, they discovered internal piping for the fuel system.
"They had written on them 'Made in Colombia, 2024,'" Reubenson said.
[map]They didn't know it until they later reported it to police, but they had discovered a narco sub — the third such vessel found in Solomon Islands' waters over the past year.
The Pacific's growing drug problem
Narco subs are ocean-going, semi-submersible or fully-submersible vessels, often custom-built by drug cartels to transfer huge amounts of product across oceans.
The practice has been going on in the Americas for decades, but the newer vessels are often fully submersible in order to reduce detection by authorities' radar or sonar systems.
This month, the Trump administration has started its own war on similar-type boats, bombing vessels it says were filled with drugs bound for the United States.
But in the Pacific and Solomon Islands, these types of discoveries are new.
Last year, a local doctor found the first narco sub in the region near Solomon Islands' isolated Ontong Java Atoll, and has now turned the 25m-long vessel into his personal boat.
Local investigative team In-depth Solomons reported that an Ecuadorian voter ID card was found on board.
And in July, the second narco sub, this one 21m long, was discovered floating in the ocean by a local MP near Ramos Island, which is about 75km north-west of the latest discovery.
All three of the vessels found in Solomon Islands had no drugs on board, with experts saying the vessels are often abandoned after a successful mission.
Local Police say they are investigating all three, and it is unclear whether these vessels drifted the 10,000km from South America, or they transferred the drugs closer to Solomon Islands.
But the discoveries come as the Pacific grapples with a growing drug problem, with a string of recent busts highlighting how cartels are increasingly using the sparse and largely unpoliced Pacific Islands as a transit point onto the more lucrative Australian and New Zealand markets — what experts call the "cash cows".
"[These discoveries] definitely show a new trend being used by trans-criminal syndicates in South America and Mexico, to traffic drugs to Australia and New Zealand, the 'cash cows' in the region," transnational crime expert Jose Sousa-Santos told RNZ.
"These vessels operate through the Pacific Islands or from island to island from a drop-off mothership to, say, the Solomon Islands.
"Then a LPV (narco sub) is used to move to another island country to refuel, before moving towards the target markets of Australia and New Zealand."
'Power drug' hits Solomon Islands
The drug importation issue has become a new and increasing problem in the Pacific Islands, hitting communities in Tonga, Fiji, Samoa and PNG.
Fiji, in particular, is grappling with a spike in HIV on the back of increased meth use in the country, with users sharing needles in what's known as bluetoothing.
But in Solomon Islands, it is so new that authorities don't even have legislation to prohibit possession of methamphetamine, which locals are calling "the power drug".
And local police say the discovery is beyond the current capabilities of law enforcement.
Prime Minister Jeremiah Manele told local media this week that the government was working urgently to address the legal gaps, aiming to modernise outdated laws to ensure stronger measures against those in the production and distribution of illegal drugs.
"As we speak the attorney general's chambers, together with other stakeholders including the police, are looking at these gaps," he said.
"This is our priority, and we want to quickly bring the necessary amendments to parliament -- hopefully by the end of this year, or if not, during the first session next year."
Local lawyer and prosecutor Steward Tonowane said the discoveries of the narco subs and the lack of legislation in Solomon Islands were a "serious concern".
"Reminds me of the saying: when there's smoke, there's fire," he said.
"There must be a deliberate orchestrated operation that is happening.
"And we must make amendments and prepare ourselves [so] that we may be able to attend to this issue."
Back in Fourau village, the narco sub has become a major talking point in the community, with everyone in the community coming to check it out.
Yet, local police have warned "the good citizens of Solomon Islands" to call police first in such encounters.
"This is for the police to come and properly check to make sure the boat is safe," the police told the ABC in a statement.
But for Reubenson, now that the narco sub has been abandoned, it's a matter of finders keepers.
"If I find this thing that no one owns, then obviously it means I'm the new owner."
