Nautical decor tends to be popular for beach houses and summer cottages. Of course, it is a style of decor that can be used at any time in any room. And something like a bedspread or small rug that features a boating-related pattern can be used in a non-nautical setting. If this is a style that appeals to you, look for sheets or comforters that feature small repetitive patterns, or big an bold designs that make a much bigger impact.
Here’s a version I really like:
Anchor design bedding set pictured: Thumbprintz Duvet Cover, Twin, Anchors Away White
Decorative items with a nautical theme are often navy blue or light blue, which makes a lot of sense, but you should be able to find them in other, less standard colors.