Clive Brook

Captain Tom Armitage

John Clements

Lieutenant Cranford

Edward Chapman

Captain Eckersley

Judy Campbell

Lucy Armitage

Penelope Dudley-Ward

Mabel

Edward Rigby

Mr. Matthews

Allan Jeayes

Commander Blount

Michael Wilding

Dot

Harold Warrender

Lt. Commander Martin

David Hutcheson

Captain Sandeman

George Carney

Bates

Al Millen

Knowles

Charles Farrell

Walker

John Laurie

Gates

George Benson

Parker

Hay Petrie

Minesweeper Skipper

Mervyn Johns

His Mate

Albert Lieven

Commander U.37

John Wengraf

Commander Deutschland

Edward Lexy

Merchantman Skipper

John Glyn-Jones

Mate

John Boxer

German Captain

John Carol

Edmonds

Alec Clunes

Bit Part

Anton Diffring

U-Boat Officer

Derek Elphinstone

Hawkins

Alf Goddard

Bosun's Mate

Stewart Granger

Sutton

Bryan Herbert

Signals Yeoman

Patrick Holt

Holt

James Knight

Admiral

Maire O'Neill

Mary Hogan

Charles Rolfe

Peacock - Wardroom Steward

Harry Terry

Sailor

Charles Williams

'Shorty' Howard

Howard Lang

Gunnery Officer (uncredited)