TIMEWATCH
THE LOST HEROES, BBC2

Working with a 1/6 scale model of the X-Craft, shots of the submarines underwater were achieved 'dry-for-wet' by shooting in a dense smoke environment. Particulate matter and plankton were achieved 'in camera' rather than by post production means.

Sequences where the submarine was seen surfacing and submerging - plus views of their quarry Tirpitz - were shot on a shallow water tank.