The nautical star is a 5-pointed star, the points are split in half and filled with an alternating color (usually black-red or black-white). Sailors used stars and the North Star (aka Polaris) for navigation, so it's not hard to see why so many of them have star tattoos. They function as a guide to get them back home safely.
Also today, people have star tattoos for similar reasons, you can rely on them when you are lost in your life, they are a light in the darkness.In Ireland the nautical star is a symbol for good health, it's an old Pagan symbol you can find in certain Irish hospitals.
The nautical star tattoo has a special meaning in the gay and lesbian community. Some gay and lesbian people have a nautical star tattooed on their wrist as a sign of their disposition. The wrist is a place that can easily be covered by wearing a watch or a bracelet. Curiously, many celebrities have a star tattoo on their wrist (see further).The nautical star is also a popular punk rock tattoo design.