Navy ranks on my grandfather's hat need to know?

My grandfather served in the US Navy in World War II and I found his hat I would like to know what do the colors mean or:My grandfather served in the

My grandfather served in the US Navy in World War II and I found his hat I would like to know what do the colors mean

or:My grandfather served in the US Navy in World War II and I found his hat I would like to know what do the colors mean

Tags:hat,found,grandfather,