Again inspired by true events, the film will chart a British businessman's failed attempt to win a round-the-world yacht race.
Marsh has narrated the story of Stephen Hawking's first marriage in his Oscar-nominated film 'The Theory of Everything'.
Firth will play the role of Donald Crowhurst, who in 1968 took part in the Sunday Times Golden Globe Race only to soon find he lacked the experience necessary to complete the round-the-world voyage. His boat was eventually found abandoned, with Crowhurst assumed to have jumped overboard and drowned, said the Hollywood Reporter.