Service Dress Blue (Yankee) uniform was for "warm weather afternoon and early evening functions such as yachting parties." The uniform was formally phased out in 2011 : r navy Blue satin v neck lace long prom dress, blue evening dress dresstby Simple Tulle Satin Dark Blue Long Prom Dress, Blue Formal Evening Dress US 8 Custom Color Chic Short Royal Blue Tulle Evening Dress Size 6 Blue