Captain's log of world's biggest solar-powered boat
6 September 2013 Last updated at 00:07 BST
The BBC has been given a tour of the world's largest solar-powered boat after it concluded a scientific expedition in London.
The MS Turanor PlanetSolar started its 2013 campaign by crossing the Atlantic in 22 days, beating its previous world record of 26 days.
The boat then became a research platform, its lack of emissions enabling it to collect measurements along the Gulf Stream without affecting them.
Captain Gerard d'Aboville gave a run down of the boat's vital statistics and explained the challenges of navigating to follow the Sun.