Jane,
Good for you. We use our CFD (Canine Flotation Device)regularly when whitewater rafting (like for the first two weeks of July) with our dog. Even for a strong swimmer, they really help keep her head up in rough water. Not all CFD's fit the same however. We like the
NRS product because the chest area is open, allowing (I think) a more comfortable fit when the dog is sitting. However, the trade off is not as much flotation. More like the current kayaking PFD's. If you make a fun game out of putting it on, it will make life easier later on.
Steve