East Anglia is a region shaped by water so it's not surprising that many inventions from the east of England are connected to the sea, either by the benefits it affords or the tragedies it causes. Dr Aarathi Prasad explores some water-related inventions - first the hovercraft , a celebrated,and at times ill-fated,British invention conceived on a stately Suffolk estate. Then she meets a husband-and-wife team who build unique flood protection barriers in a Norfolk blacksmith's forge, after which she tackles the challenge from a serial Essex inventor who makes filthy water safe to drink. Finally, there's a 19th-century eccentric who designed life-saving apparatus that is still used today the world over.