Submarine On Patrol | Royal Navy Propaganda (1943)

A British World War II information film describing to the public the technicalities and roles of Royal Navy submarine operations.
Filmed aboard the operational submarine HMS Tyrant, the documentary narrator offers a sketchy overview of a patrol - taking viewers from departing a Submarine Depot Ships diving, submerged operations, watch operations and practice/dramatised attacks.
While this documentary appears to have been made at the same time as filming for the propaganda movie "Close Quarters", most of the footage is unique.