It was at Somerleyton Marina where Christopher Cockerell began his work on ideas to make a boat go faster, which led to the invention of the Hovercraft - Link - the first patent being applied for in December 1955.
The red flag over the bridge doesn't indicate "danger" as stated in the image of the train crossing the bridge. One flag means the bridge is operational, whereas two flags above eachother indicates that the bridge will not open.