Life jackets are great for dogs. They have that handy strap so you can pull them back in the boat. My dogs grow up on the water, In canoes, rafts, power boats and drift boats.
I used to have a sailboat on Lake Tahoe for years. My two dogs would ride on the top of the cabin. One day with light breezes we got hit by a puff on the big mountain lake. My big BC Chelan, rolled into the lake in over 100 feet of water. She was my all-time best swimmer. She was paddlin along behind the boat, but losing ground. I could not go fast enough to turn around and come back and get her. I just told her in a stern voice to "Go Home." She turned around and paddled away from the boat. I turned around and retrieved her with a boat hook.