Navy seems to be a really popular color with our brides here in WNY this year- we already have three weddings coming up with navy blue as one of their colors! We have a navy and teal "peacock feather" wedding, a navy and white nautical, and a navy, platinum, and cream "bling" wedding.
For a navy and white nautical wedding, I think a splash of apple green is the perfect, unexpected color to take typical to fantastic. Any splash of a bright color will do, but my favorite right now is apple green. :) Here's a pretty navy and apple green color board, although not necessarily nautical, it shows the color combination quite well. I used the Dessy Styleboard for this one.