Our old girl also hates being on the boat. She is fine when now (after 5 years) when we are on our home mooring and not moving, but hates being inside the boat on the move. We only have a very small trad stern so she has to come inside when locking and then I stay with her but try to avoid reinforcing her fears by being very calm when she is getting worked up but still being there for her. When she can go on the stern she will settle down and sleep quite happily and does not fuss, but we are very careful to keep away from the bank in bridge-holes etc, or she will jump off to land. I don't think we will ever cure her of this so we plan for short days with frequent breaks when she can get off for a walk. Our other dog, on the other hand, is just fine and tends to curl up to sleep as we travel. I wish you good luck with your dog.