When I was a kid....Christmas was all about the smells as well as the decorations. I really like some small amount of pine, cinnamon, gingerbread etc.
We used to make a very simple decoration using an apple.
Core half way through so it can hold a candle ( scented is nice). Poke whole cloves in the apple on its upper half. Poke holes with an ice pick around the bottom and add pine branches. Set the whole thing in a fire safe bowl and place in the center of your table. Looks and smells like
Christmas, inexpensive and lasts for a few weeks.
Play
Christmas music and put up a strand of led lights. Cook up some hot spiced cider and either bake or pick up some gingerbread cookies!
Outside you could put a wreath or swag tied to the mast ....with a big red bow. You could put some led lights in it that can be lit at night. Simple and easy to stow quickly should you want to sail. Put the apple bowl in the sink for sailing.