NCLH (the holding company of Norwegian Cruise Line, Oceania & Regent) announced EIGHT new ships, four of which are going to Norwegian, two of which are going to Oceania, and two of which are going to Regent. The two ships going to Regent are detailed in other contributions to this thread, but they are 38% heavier in tonnage & will carry 14% more passengers.
The "hybrid" character reported for these two Regent ships may mean that the 38% "weight gain" is not just SIZE-related. I'd suspect that weight gain is apportioned between a) supplemental alternative propulsion characteristics (e.g., perhaps, engines to burn ultra-clean LNG for transiting sensitive areas . . . maybe even augmented by batteries (which are VERY heavy) added atop the standard bunker fuel & low-sulfur diesel engines) and b) additional space onboard to accommodate 100 additional passengers.