I've found that religous services often depend on whether there's someone on ship to conduct them. Check your Princess Patter (your daily 'newspaper'), it will say there if a service will be held and/or if seeking someone on board to conduct a service in a particular denomination. It may help to mention at the Pursers's or Hotel desk you're interested in services; sometimes they can get you in touch with other passengers who have expressed similar interest and you may be able to share at least a small devotion or service with others. Or, if you know that you're in a port on your day of worship you might be able to research and find a church to attend there, which could be very interesting. There's never been an organized Lutheran service on any of my cruises, but I have seen Catholic and Jewish services listed. Good luck, and enjoy your cruise!