In April 2010, William Trubridge broke a free-diving world record in the blue hole reaching a depth of Шаблон:Convert without the use of fins (Constant Weight Without Fins). On 14 December 2010, he swam to a depth of 101 metres on a single breath using only his hands and feet for propulsion, while many divers use weights to quicken their descent or inflatable bags to bring them to the surface quickly.Шаблон:Cn
Blue hole is a term which often is given to sinkholes filled with water, with the entrance below the water level. They can be formed in different karst processes, for example, by the rainwater soaking through fractures of limestone bedrock onto the watertable. Sea level here has changed: for example, during the glacial age during the Pleistocene epoch (ice age), some 15,000 years ago, sea level was considerably lower. The maximum depth of most other known blue holes and sinkholes is Шаблон:Convert, which makes the Шаблон:Convert depth of Dean's Blue Hole quite exceptional.
Dean's Blue Hole is roughly circular at the surface, with a diameter ranging from Шаблон:Convert. After descending Шаблон:Convert, the hole widens considerably into a cavern with a diameter of Шаблон:Convert.
Some water-filled sinkholes are deeper than Dean's Blue Hole, Zacatón in Mexico (Шаблон:Convert) and Pozzo del Merro in Italy (Шаблон:Convert) among them. Dean's Blue Hole though is the deepest known sinkhole with entrance below the sea level.
- Dean's Blue Hole entry and exact location on Bloosee
- The Blue Holes Foundation
- Vertical Blue
- Underwater base jump into blue hole (Guillame Nery, Julie Gautier)