HARARE — At least 15 people have died and 27 others remain missing after an overloaded ferry capsized on Zimbabwe’s Lake Kariba, according to the Civil Protection Unit. The ferry overturned on Tuesday after encountering strong waves while travelling between the northern town of Kariba and several islands and fishing camps. The Civil Protection Unit said at least 77 people had been rescued, while warning that the final number of people on board remained unclear. Although the vessel had a capacity of 90 passengers, registered ticket sales showed that 114 adults and five crew members were on board at the time of the accident. Authorities said there could also have been children on the ferry who were below the ticketing...