A sailors-trapped-in-a-sinking-submarine drama: Will they drown? Will the oxygen run out? Will they suffocate from chlorine gas? Will divers get to them in time? And what about that religious fanatic on board? John Ford skillfully ratchets up the tension, but some shaky special effects, unlikely characterizations and broad acting give an uneven effect, compared to later and slicker entertainments like RUN SILENT, RUN DEEP. However, this production has genuine historical value because it shows the difficulties in changing over from silent to sound,: sometimes it's a silent film with sound effects and [tinny] music. Other scenes have dialogue with one character actually speaking while another answers in silent intertitles. Most oddly, sometimes a character starts speaking, then an intertitle shows noticeably different lines, then the character finishes speaking. Not many movies have such a variety of expression.