The Hunt for Red October (film) essentially revealed the use of gravimetry as a method of silent navigation in US submarines. Thought to be a billion dollar black project, the development of a full-tensor gravity gradiometer by Bell Aerospace was a classified technology at the time. It was thought to be deployed on only a few s after it was first developed in 1973. Bell Aerospace later sold the technology to Bell Geospace for oil exploration purposes. The last Typhoon-class submarine was officially laid down in 1986, under the name "TK-210", but according to sources was never finished and scrapped in 1990. The musical score of
The Hunt for Red October are many deviations, including "Red October" traveling up the Penobscot River in Maine to dry dock, and the "caterpillar drive" being described as a magnetohydrodynamic drive system, essentially, "a jet engine for the water". The film received mainly positive reviews from critics, holding an 87% rating from Rotten Tomatoes based on 66 reviews. It was the 6th top-grossing film of the year, generating $122 million in North America and more than $200 million worldwide in box office. In a 1991 interview, Clancy remarked of the film's success: "It was reasonably true to the spirit of the book, although the movie