Controlled by a pilot lying prone, Deep Flight 1 was a submersible used in the 20th century on Earth for oceanic exploration. The submersible's movements were guided by short inverted wings placed along either side of the hull. A camera placed above the pilot's chamber was used for filming. (ENT: "Broken Bow")
The submersible Deep Flight 1 is seen in the opening credits of Enterprise. It is not mentioned by name, and its name is from the historical records.