Most of the bigger cruise lines such as Crystal, Holland America, Celebrity, Azamara, Royal Caribbean, Disney, Carnival, etc are now staffing up with clergy to come on the trips. These are usually retired men (sorry ladies, not yet) who pull a free trip in exchange. The ships do not dedicate much real estate to religious needs, but a few do have free standing chapels.

Most just have a resident priest, rabbi or non-denominational preacher on board. Services are announced in the daily newsletter with religious feasts and holy days drawing big crowds. Usually the theater is transformed for the one-hour service. Passengers often help out with readings or other rituals.
As speakers we need every bit of help we can get. A short chat with the clergy can help settle our nerves and put things in perspective. I’ve found them to be outgoing and giving.