The Phantom Submarine (1940)

On the night before he sails in search of the steamship Arcadias sunken gold Paul Sinclair Bruce Bennettmeets Madeliene Nielson Anita Louise in a San Francisco nightclub On the second day at sea Madeliene turns up as a stowaway While diving and searching for the sunken gold off the Phillipines Paul discovers that a foreigncountry submarine has been laying mines in order to completely cut off the Phillipines from American protection