Satellite, Cable & Digital: PICK OF THE DAY

Marine Machines (10pm National Geographic )

While humankind is already well on the way to charting outer space, many natural phenomena on this planet remain mysterious to us. This applies particularly to the oceans that cover two thirds of the earth's surface, and Marine Machines follows some of our more imaginative efforts to master the world's great bodies of water. Among the subjects of this 13-part series are the activities of the huge machines capable of repairing underwater oil pipelines, and the latest stealth warships capable of evading enemy radar systems.

Tonight's series opener focuses on attempts to combat the dangers posed to shipping by icebergs in the North Atlantic. This episode follows the aircraft and ships that patrol the sea off the coast of Greenland looking for icebergs and breakaway pack-ice. Some icebergs are the size of a submerged 15-storey building and the teams sent to neutralise them employ a range of techniques including tow ropes, explosives and water-cannon.