Old ships, powered by the wind, are sailing small amounts of cargo around the world again to help cut pollution. Some of them were built more than 100 years ago. The shipping industry moves 80% of traded goods around the planet. But the diesel engines that propel modern cargo ships through the oceans burn the dirtiest type of fuel. Nick Holland speaks to sailors and brokers who, for the sake of the environment, are breathing new life into these vintage vessels. And he hears how new types of sails could get monster-sized modern cargo ships using the wind as well. Producer / Reporter: Nick Holland