Mar de fondo
Título original: Seas Beneath
En los últimos días de la Primera Guerra Mundial, el estadounidense "Mistery Ship" zarpa de la costa de España. Su misión es encontrar y hundir un submarino que ha sido especialmente eficaz en atacar buques aliados. Haciéndose pasar por una goleta inofensiva, el "Mistery Ship" está equipado con un cañón formidable capaz de hundir submarinos.
Reparto
| Actor | Papel |
|---|---|
| George O'Brien | Cmdr. Robert 'Bob' Kingsley |
| Marion Lessing | Anna Marie Von Steuben |
| Mona Maris | Fraulein Lolita |
| Walter C. Kelly | Chief Mike 'Guns' Costello |
| Warren Hymer | 'Lug' Kaufman |
| Steve Pendleton | Ens. Richard 'Dick' Cabot (as Gaylord Pendleton) |
| Walter McGrail | Chief Joe Cobb |
| Larry Kent | Lt. 'Mac' McGregor |
| Henry Victor | Baron Ernst von Steuben (U-boat commander) |
| John Loder | Franz Shiller |
| Philip Ahlm | German Chief Petty Officer (uncredited) |
| Al Bennett | Naval Reservist (uncredited) |
| Earl Wayland Bowman | Naval Reservist/Swimmer and Diver (uncredited) |
| Bill Brande | Naval Reservist (uncredited) |
| William Collier Sr. | Mugs O'Flaherty (uncredited) |
| Leonard Davison | Naval Reservist (uncredited) |
| Joseph Depew | Naval Reservist (uncredited) |
| Francis Ford | Eric - Captain of Trawler (uncredited) |
| Robert Ford | Naval Reservist (uncredited) |
| Hans Fuerberg | Fritz Kampf (Second Officer of U-172) (uncredited) |
| Curt Furberg | Hoffman (uncredited) |
| Al Generaux | Naval Reservist (uncredited) |
| Bob Gillette | Naval Reservist (uncredited) |
| George Golden | Naval Reservist (uncredited) |
| Ben Hall | Elmer Harrigan (uncredited) |
| George Harris | Naval Reservist/Swimmer and Diver (uncredited) |
| Bob Kyle | Naval Reservist (uncredited) |
| Jack Martin | Naval Reservist (uncredited) |
| Harry Mount | Bugler on Gun Crew (uncredited) |
| Jack Murphy | Naval Reservist (uncredited) |
Equipo
| Role | Name |
|---|---|
| Writer | Dudley Nichols |
| Director | John Ford |