John Tollerton is the fifth generation in his family to work at the Harland and Wolff Belfast shipyard, most famous for its mammoth task of building the world’s then biggest ship, the Titanic, in the early 20th century. Mr Tollerton’s grandfather was one of the many thousands of men who helped build the liner during the shipyards heyday. Now a century later, the Belfast shipyard is taking on a more sustainable direction by establishing a foothold in the green energy sector.