The pit bulls weren't too bad to get back on the dock. If we had to get them back onto a boat or into a dinghy it would be more difficult, for sure.
We once had our 150 pound St. Bernard fall inbetween Pam's Tanzer 26 and a rickety dock. He was difficult to pluck out, but adrenalin is an amazing thing.
Cats can rescue themselves. Gertie, our small cat, fell in at Atlantic Highlands, NJ. To rescue herself, she had to climb about ten feet up a piling.