Abyss of Hranicka Propast, the deepest underwater cave

20 years of exploration of the unusual cave has just given an incredible result – the world record for the deepest underwater cave.

Dive into the Abyss of Hranicka Propast – the deepest underwater cave

Text Marcin Jamkowski

Photo Marcin Jamkowski, Krzysztof Starnawski

20 years of exploration of the unusual cave has just given an incredible result – the world record for the deepest underwater cave.

The entrance to the cave looked like a rim of a volcano. Hiking up a gentle hill through oak and beech, they found the top had collapsed and formed a caldera.

Rappelling down, instead of molten lava divers found a murky lake on the bottom, covered with brownish leaves and rotting logs sticking out.

The uppermost part of the thermal waters system; the lake stays 15 C year round and never freezes.

Just this past Tuesday, Sept 27th 2016, the expedition proved this cave to be the deepest underwater cave on the planet with an astonishing depth of 404 meters.

The descent

The place is called Hranicka Propast, or The Abyss of Hranice, and is located in the north of Czech Republic near the town of Hranice, an hour’s drive from the Polish border.

The cave has been explored for the last 20 years by Krzysztof Starnawski, an extreme cave diver with many records on his account, and a big Polish-Czech team of 20 volunteers he leads together with strong Czech divers David Čani, Miroslav Lukáš and Michal Guba.

Starnawski’s scuba dives took him to increasingly greater depths: 181 meters, 200 meters, 230 meters, and finally he reached 265 meters last year (a dive demanding 8-10 hours of decompression).

At this point he decided to change approach and try electronics with the help of Bartłomiej Grynda, a Polish constructor of underwater vehicles from GralMarine.

Hitting a world first

Starnawski dove to 200 meters where he fixed a bright yellow guide line, along which the two men sent down a specially upgraded version of Grynda’s ROV (remotely operated vehicle).

Operated from the surface by a fiber optics cable, the vehicle was equipped with compass, professional depth gauge (tested by the state certification authorities), four HD cameras and a pack of very strong LED lights.

The goal: navigate through the shafts, reach unknown territory and push forward.

The ROV went into the yet unexplored part of the cave. The corridor was still wide. It narrowed for a moment and opened again. As the robot swam past the 392 meters mark we shouted: “We have the World Record!”

And it went even further. A few minutes later it passed our expedition milestone – 400 meters! After a while the bottom showed up covered with a tangle of fallen trees, branches and rubble.

Finally the vehicle remained hanging in the water at a depth of 404 meters. With still some blue abyss under. Unknown. For now!

Marcin Jamkowski

The expedition was supported by The National Geographic. Visit https://www.nationalgeographic.com/adventure/activities/caving-and-canyoneering/deepest-underwater-cave-discovered/ to learn more

Posted by Piotr Chmielinski