The Hunt for Red October Reykjanes Ridge off Iceland. "Dallas" hears the sound of the stealth drive but does not identify it as a submarine. As tensions rise between the U.S. and Soviet fleets, the crew of "Dallas" analyzes sonar tapes of "Red October" and finally realizes that it is the sound of a new propulsion system. Meanwhile, CIA analyst and former Marine Jack Ryan, who was initially tasked to examine MI6's photographs of "Red October", finds out that the submarine's new construction variations house its stealth drive. Later putting information about Ramius's letter together with the subsequent launch of the entire Northern Fleet, Ryan
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