Exactly. You need to start at home. Perhaps he has a favorite place next to the house where he usually goes. So put the astroturf there, or even slip it under him as he starts to go. Soon enough he will realize that it is okay to use the astroturf. Get him into that habit and it is a fairly simple matter of moving the astroturf around until he figures out that wherever it is, that's where he's supposed to go. Now put it on the boat, et voila!In my experience the trick to making this work is using that same piece of astroturf at home.