Royal Caribbean Cruises will rely mostly on exhaust gas scrubbers to bring its fleet within the IMO's 2020 sulphur cap, with roughly two-thirds of its ships poised to carry the systems.

The New York-listed cruise company has worked for a number of years on putting "advanced emission purification", or AEP, systems on 20 of its 49 passengerships, said president and chief operating officer Adam Goldstein on the sidelines of the Seatrade Cruise Global conference in Fort Lauderdale.