Real-Life Communication -- Solution
Here's one way to display the insignia:
Top row -- Chief petty officer to master chief petty officer
Center -- The three petty officer classes from third to first
Bottom -- The three seaman ranks from recruit to seaman
This way, each ranking would be organized together. You could follow the natural progression of your customer's promotions throughout his career.
All the seaman insignia are black blocks beginning with a single slash of white at the recruit level and adding another slash for achieving first apprentice and then another slash for full seaman status.
The petty officer class insignia are also on a black field. However, these have a "V" bottom and contain two figures, an eagle and crossed anchors.
A single "V" in red across the bottom of the black field indicates the lowest class of petty officer, petty officer third class. Each step through the classes adds another red "V" until petty officer first class has three "Vs."
The insignia for chief petty officer changes one of the elements from the petty officer first class insignia. The crossed anchors now become a ship wheel.
An additional element is also included in all three chief insignia. A red arc closes in the top "V" slash. When a chief petty officer is promoted to senior chief, a single white star is added above the eagle. When the senior chief is promoted to master chief, another white star is added.