We went to services on the May Repo. It was just a handful of passengers in the theater (the second Sunday it was in Studio Sea) and lead by a Cast Member. They had some music to play some hymns and the cast member did a couple readings. Personally, if you could privately reflect over some readings, you may get more out of some quiet time on deck. (We only went both Sundays because my Mom feels she is missing out if she doesn't have group service.) I believe this is their norm. If they have someone on board as a guest that volunteers to lead services, then they may have something more elaborate -- but I would think this would be uncommon outside holiday time.