Two Burmese fishermen say they survived for almost a month in shark-infested waters by floating on a large ice box after their fishing boat sank on December 23 because of bad weather. The men, who are both in their 20s, were spotted by an Australian coastal patrol aircraft at the weekend and winched to safety by a helicopter. The fishing boat sank in heavy seas off the north coast of Australia 25 days ago and 18 people died. The survivors were hungry and thirsty and were taken to hospital. Health chiefs said the pair were recovering well and had already been released from hospital. The men will now be questioned by police and immigration officials who want to find out how they survived. Investigators want to find out what the men ate and drank in the ice box, which was about the same size as a large desk.