how deep can man dive in the ocean
Deep diving Amongst technical divers, there are divers who participate in ultra-deep diving on SCUBA below 200 metres (660 ft). This practice requires high levels of training, experience, discipline, fitness and surface support. Only twelve persons are known to have ever dived below a depth of 240 metres (790 ft) on self-contained breathing apparatus recreationally.[21][22][nb 4][nb 5] That is the same number as the number of people who walked on the moon. The Holy Grail of deep scuba diving was the 300 m (980 ft) mark, first achieved by John Bennett in 2001, and has only been achieved five times since.
Mariana Trench Four descents have been achieved. The first was the manned descent by Swiss-designed, Italian-built, United States Navy-owned bathyscaphe Trieste which reached the bottom at 1:06 pm on 23 January 1960, with Don Walsh and Jacques Piccard on board.[13][22] Iron shot was used for ballast, with gasoline for buoyancy.[13] The onboard systems indicated a depth of 11,521 m (37,799 ft), but this was later revised to 10,916 m (35,814 ft).[23] The depth was estimated from a conversion of pressure measured and calculations based on the water density from sea surface to seabed.[22]