We have a 14 yr. old dog who bites if we try to pick him up as well, so in and out of the dinghy
or to the dock
if we cannot use the passerelle we put his life jacket on. This doesn't seem to bother him, much. We take it off once on shore so as not to over heat him.
He had a problem with the stairs at first. I took some spongy cabinet lining "paper" you buy at the grocery and used sticky tack (found at hobby lobby) to secure it to the steps. Now he has no problem up or down. The sticky tack is re-useable and does not leave a stain. I also discovered that there is a lot less dirt in our hulls because of this.
We just bought a Pet Potty, basicallly a piece of astro-turf. I tried everything, putting some of his "business" on it, using commands, treats, a dog trainer even to me to pee on it. That didn't work so well. Finally after being unable to go ashore for 2 days he broke down and peed on it. 2 days later when we returned to shore he still had not pooped. He doesn't like to use it because we've taught him not to go in the house. I put it on the starboard aft deck
because it's easy to clean up from that location and that is also where we exit the boat.
a puppy in hopes that the old dog will go where the new dog goes.
By the way, we put netting on our life lines to make sure the dog stays on the boat when we need him to.