Bathyscaphe Trieste
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of , although this was revised later to ; fairly recently, more accurate measurements have found Challenger Deep to be between and deep.
George Stephen Ritchie
From that time he worked continuously in that branch of the Royal Navy travelling all over the World and commanding four of HM surveying Ships: on a world circling voyage with scientists on board; HMNZS "Lachlan", the New Zealand survey ship; , in the Persian Gulf and in the West Indies and North Atlantic. In 1951 on the survey ship HMS "Challenger", recorded the deepest part of the ocean trench depth Challenger Deep of 5,960 fathoms (10,900 m, 35,761 ft) using echo sounding. He was awarded the Royal Geographical Society's Back Award in 1954.