Cindi, Strangely enough Walter the farting dog books are some of my favorites, along with Harry the Dirty Dog and Harry by the Sea. It took me a while to find the book I was referring to earlier but alas after calling out a search party and attempting to get to the bottom layer of stuff in dd's room I found it!
"Samantha's Ocean Liner Adventure" it is part of The American Girl's Collection. Here's a link to purchase it at about half price. It's a really cool book, for a girl or a boy.