When an organisation earns the prefix “Royal” it normally incorporates the crown of the current monarch in its insignias. This especially applies to military units. Currently the Junior Rates of the Royal Navy wear no crowns on their uniforms in any place.
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Being a Royal service, I believe that it does a disservice to those of the lowest rates of the Royal Navy to not be able to show this Royal status in any way, when other service people do so proudly. This is highlighted more when the Senior Rates and Officers of the Royal Navy and members of the Royal Marines do wear crowns.