OTTAWA—The Royal Canadian Navy is investigating an unexplained breakdown on its brand-new, $400-million Arctic patrol ship. The problem first emerged last week as HMCS Harry DeWolf’s crew were training off the coast of Halifax, 2-1/2 months after Irving Shipbuilding delivered the vessel to the Navy. Commodore Richard Feltham, commander of Canadian Fleet Atlantic, says the ship was forced to return to port after its freshwater generator and communications systems didn’t work. It was while the ship was docked that the crew found the cooling pumps on two of the ship’s four diesel generators had broken. The problems with the freshwater generator and communications system have been resolved, according to Feltham, who said the navy is confident about the causes and solutions. Though the cooling pumps were also fixed and the Harry DeWolf is back at sea for training, Feltham said the navy is investigating why to ensure there isn’t a …