How large of a dog is this?
We've always had smaller dogs on our boats, except for visiting family/friends with large dogs. Even with the high free-board of our last boat, Bryer, our daughter's 70 lb. yellow Lab, wasn't much of a problem.
When boarding, we tied the dink alongside a removable boarding
ladder and simply lifted him through the boarding gate. You will find that (most) dogs will assist you by kicking off the dink's gunwale with his hind quarters, while using the front legs to lift himself aboard. We are friends with several cruising sailors with larger dogs who use the same technique.