A British rower who has paddled across some of the world's biggest seas to raise environmental awareness left Australia Wednesday hoping to cross the Indian Ocean and complete a personal hat-trick. Roz Savage, 42, set off from the western Australian city of Fremantle bound for Mumbai's Gates of India monument, an epic 6,500 kilometre (4,000 mile) journey that will take between five and six months. Savage has already crossed the Pacific and Atlantic oceans solo in her 23-foot (seven-metre) rowboat, dodging fierce storms and near-drownings. The Indian Ocean voyage -- her longest single row to date -- will cap the "Big Three". The keen environmental campaigner hopes to raise money and awareness about ocean pollution. "It's mostly a question of holding it together mentally, staying reasonably happy and focused and just keep sticking the oars in the water," Savage told reporters ahead of her departure. "It sounds pretty straightforward but 12 hours of rowing a day can be a little bit challenging at times." She will subsist on freeze-dried meals and nuts and convert saltwater into drinking water with a miniature desalination plant on board. Savage had originally planned to make her way to Zanzibar, off eastern Africa, but said escalating piracy had forced her to rethink the route. She will update her blog regularly but will not be publishing exactly where she is in order to elude the pirates. "I'm trying to get the message out there that we need to take better care of the earth if we're going to have a long-term and healthy future as a species," Savage said. "It's not just about raising awareness, but to take some action too."