Dog Whisperer
Wchevron: Get some dvd's of the Dog Whisperer show (available at Netflix, among other places). The guy who does the show, Cesar Milan, has some interesting techniques to help dogs get over phobias. According to him, age doesn't matter; dogs live day-to-day.
Our dogs were about four and two when we first took them on a boat. The older one - a lab mix - thinks it's just a car with one big window to look out of, or sleeps. The other gets a little nervous when the seas get choppy.