A new type of propeller that helps boats reverse is demonstrated in factory in Charlton.
Title reads: "New propeller varies pitch".
Panning shot Port of London docks with cargo ships loading and unloading. L/S of tug berthing a cargo ship. C/U of foam being churned up by tug's propeller. L/S of tug berthing cargo ship.
Interior. L/S of factory floor; men are working on new type of ship's propeller with variable pitch. C/U model the new propeller with the blades' pitch being varied. Side shot, showing the blades moving in the two directions. M/S of the technician operating the model. Top shot and side shot, looking down on the model as it revolves, with the blades altering their pitch. The variable pitch means vessels can be thrown into reverse more quickly.
Extreme C/U of finger pointing to diagram of the new prop. More shots of propeller on factory floor being demonstrated. C/U of gauge on machine. More shots of propeller.
Note: according to newspaper article on file factory is the Stone Marine Engineering Company.