What to wear for a party themed "i'm on a boat?"?

i'm going to a party and the theme is "i'm on a boat" (after the SNL skit with andy samberg & t-pain). i figure i can do something nautical like, but what types of shoes/accessories? i know red, white, & navy blue are good colors. i'd like to try to use some things that i have rather than going out and buying a costume too. any ideas? thank you!