Complex sentence: It is based on the best selling novel "The Cruel Sea" by former naval officer, Nicholas Monsarrat, though the screenplay by Eric Ambler omits some of Monsarrat's grimmest moments.
Split into simpler sentences: It is based on the best selling novel "The Cruel Sea" by former naval officer, Nicholas Monsarrat. Although the screenplay by Eric Ambler omits some of Monsarrat's grimmest moments.