Which Soviet vessel recorded 11,034 m in Challenger Deep in 1957?

The Soviet vessel that recorded 11,034 metres in Challenger Deep in 1957 was RV Vityaz.

Vityaz, operated by the Soviet Union’s Vernadsky Institute of Geochemistry, surveyed the Mariana Trench during Cruise 25 in August 1957. Its single-beam soundings reported an exceptional depth of 11,034 metres in the western basin of Challenger Deep.

That figure is historically important but should not be confused with today’s accepted measurements. Later researchers considered the Vityaz readings statistical outliers, partly because early soundings had less precise navigation and required difficult sound-velocity corrections. Modern surveys generally place Challenger Deep at roughly 10,900–11,000 metres.

Vityaz returned in 1958 for a broader survey. The famous 11,034-metre figure therefore belongs to the vessel’s 1957–1958 Challenger Deep work, while HMS Challenger and Trieste are associated with other landmark expeditions and dives.