A guy earlier mentioned Load-a-pup, It has changed the way I boat!
We just love ours, and the dogs come and go as they please. We don't
do a thing. It's awesome.
As can be seen in my avatar, I take my little boy out with us all the time. He loves the water and the boat. I too am afraid that he will jump out. Hence, the life jacket. He wears it from the truck back to the truck. We keep a leash on him while the boat is underway. So far so good.
A few years ago a dockmate was taking his dogs to the beach and he saw what he thought was a yellow beachball and went to pluck it out of the water and give it to his dogs to play with. It turned out to be a terrier in a yellow vest.
We love to take the pup out on the boat. She did not like going in the water the first year at all. Now as soon as she sees her life vest she goes nuts. She'll jump right in the water and swim to the boat. When we raft up I do have to keep an eye on her cause she has jumped off the boat to go visit other boats. She will swim right up to your platform. (I am working on teaching her how to ask permission to board) Here she is after swimming with the kids.
The only issue I ever have with her is once she gets to shore she is a runner and I am not. So as long as I keep her on the leash near shore we don't have to play the chase game. The kids want to take the cats on the boat but thats a whole different story.