Repeat: The submarine is 6.5ft (two metres) long and operates at a depth of 66ft to 98ft (20 to 30 metres), bouncing sound waves off the under-surface of the ice.
The submarine is 6.5ft (two metres) long and operates at a depth of 66ft to 98ft (20 to 30 metres), bouncing sound waves off the under-surface of the ice.