In August 2006, the crew of the yacht Maiken, sailing out of the Vava’u island group, encountered a remarkable “stone sea.” The phenomena they spotted were a series of pumice rafts resulting from a nearby eruption, one that was forming a new volcanic island in Tonga:

Amazing Sight in the Pacific August 2006, the yacht ‘Maiken’ is traveling in the south Pacific when they came across a weird sight… It was sand in the water, and floating ON TOP of the waves… This is not a beach, it is volcanic stones floating on the water. The trail left by the yacht… And then this was spotted … ash and steam rising from the ocean … And, while they were watching … A plume of black ash… A brand new island formed…

As Maiken crewmember Håkan Larsson reported in his blog entry for that day:

We left Neiafu and Vava’u yesterday after some tedious checking out procedures and set sail for Fiji, passing the north side of Late island as first way point. After five miles we noticed brown, somewhat grainy streaks in the water. First we thought that it might be an old oil dumping. Some ship cleaning its tanks. But the streak became larger and more frequent after a while, and there were rocklike brownish things the size of a fist floating in the sea. And the water were strangely green and “lagoon like” too. Eventually it became more and more clear to us that it had to be pumice from a volcanic eruption. And then we sailed into a vast, many miles wide, belt of densely packed pumice. We were going by motor due to lack of wind and within seconds Maiken slowed down from seven to one knot. We were so fascinated and busy taking pictures that we plowed a couple of hundred meter into this surreal floating stone field before we realized that we had to turn back. Just as we came out of the stone field and entered reasonably normal water we noticed that there came no cooling water from the engine. Not surprising, really. After cleaning the water filter the Yanmar diesel started again. Thank God! Without wind we would have been stuck in a sea of stone if the motor had failed. Next thing to check was the other water inlets. Some minor pumice particles but nothing serious. But the bottom paint were scrubbed away at places along the waterline, Maiken has an ablative paint so it was just doing what is supposed to do. Like we’d sailed through sandpaper. So, we headed back east to get away from the stony sea. There are two active volcanoes south of Late island, adjacent to Metis shoal and Home reef. Since we didn’t know which one had erupted, the extent of the eruption and it was getting dark the we decided to anchor in Vaiutukakau bay outside Vava’u for the night. The sky darkened fast from rain clouds over Vava’u and we sailed leaving the stone sea onto darkness towards a perfect rainbow ahead, like a big welcoming arcade. It was completely dark when we anchored close to land at 25 meters depth. In the morning we woke to birds song. Lot of birds nesting on the steep hillside next to us. After checking the motor and boat we set out again. We decided to go south of Metis reef to go clear of the stony debris. Just after leaving Vaiutukakau bay we encountered three whales, probably two males and a female, playing in front of us. They circled around the boat only meters away for a while, seemingly interested of Maiken, before swimming away. A couple of hours ago we identified the active volcano as the one close to Home reef, and we are on our way there now to take a closer look. We are two miles from it and we can see the volcano clearly. One mile in diameter and with four peaks and a central crater smoking with steam and once in a while an outburst high in the sky with lava and ashes. I think were the first ones out here so perhaps we could claim the island and name them(?)

Alas, the island didn’t last very long. By the time volcanologist Scott Bryan of London’s Kingston University managed to get out to the area a few months later to see it for himself, it was nearly completely washed away, leaving only the lingering scent of sulfur — a clue that magma was still cooling inside.

A rehash of this item was run under the clickbait headline “When This Boat Crew Realized What They Were Seeing, It Was Almost Too Late to Escape” and falsely suggested that the Maiken‘s crew barely escaped death while viewing the eruption (from a safe distance):