Traditional cruise majors are looking towards LNG to reduce ship exhausts' sulphur content, but expedition operators say the fuel is out of reach for them for now.

Miami-based Carnival Corp has ordered 11 LNG-powered ships due by 2025 and has two vessels on the water that use LNG in port.

"LNG is an economic, clean and safe marine fuel with increasing global availability that also complies with existing and scheduled emission requirements," Tom Strang, Carnival senior vice president of maritime affairs, tells TradeWinds.