TReilley has one of the sweetest boat dogs!
Our requirements when looking for our mutt were that the dog would be small, non- or low-shedding, and a baby/young enough to learn that on deck was okay to do her business on. We ended up with the best mutt possible! She's a cairn terrier x shih tzu (not as floofy as it sounds), loves the boat and ESPECIALLY dinghy rides, and has never lived anywhere else so she feels comfortable there. She only "sheds" when you brush her snarls out, but we have a cat who sheds plenty for both of them.
She has a harness and a life jacket, but on calm days she doesn't wear them. She can't get up the companionway on her own but she jumps right onto your shoulder to come in, and asks to be let out when she has to go. Also have not found her to be at all "yappy" as little dogs can be, the only thing that really sets her off is skateboards (she HATES them -- we joke that she's worried the riders aren't wearing appropriate safety gear).