I have asked this question on many CPAP and Apnea boarda, and got the same answer. I am a first time cruiser, sailing on the Coral Princess on 3/22. I would appreciate any CPAP or BiPAP users posting their experiences.
I travel with my CPAP and have not had any problems using aboard any ship. Bring an extension coard as the outlet may not be close to the bed. Power strip may work, most contemporary ships have a 3 prong outlet. You may want to pack a 3 / 2 prong adapter. But more important would be the extension cord for access to an outlet.
I just use an extension cord, and plop the machine and extension in a drawer after the night's use.
Retired CD & ShorEx: Royal Cruise Line; Radisson Seven Seas: Celebrity; Holland America; Premier; NCL.
I had my Cpap machine on the Sensation with me and didn't even need an extension cord. The cord on the machine was long enough. It is 6ft. the plug was at the sitting table but my bed was close to it. I had no problem and left my extension cord (still in a wrapper) in the room for the steward, thinking maybe someone else may need one.