Titanics Tragic Twin: The Britannic Disaster is a 2016 English-language Documentary History movie. The Titanic's twin sister, the Britannic, was bigger and better built, but she sank to the bottom three times faster. Why she sunk has remained a mystery until now. Titanics tragic twin: the britannic disaster features Kate Humble, Andy Torbet, Simon Mills, Margaret Meehan, Richard Kohler, Tamsin Jewell and Daniel Little. The Titanic's twin sister, the Britannic, was bigger and better built, but she sank to the bottom three times faster. Why she sunk has remained a mystery until now.