Underwater positioning equipment is the name of the game for Sonardyne, a family-run company based in Hampshire. Sonardyne caters for the needs of the offshore oil and gas industry by providing services such as positioning pipelines on the sea bed, tracking underwater vehicles, and establishing subsea communications. Established in 1971, Sonardyne has expanded and is now an international operation, with offices in Scotland, US, Singapore, Brazil and Norway. Group MD Barry Clutton has recently opened new premises of Sonardyne Inc in Houston, Texas. Despite its size, it is still a family business that doesn’t court the limelight for fear of unwanted attention from potential buyers. With turnover at £47.9m and compound growth at 52.9 per cent, you can see why it looks attractive.