Yea as much as i hate to send anyone to walmart, walmart has them as well as
pets stores. Our dogs usually hold it like hell the first day underway, then once they decide they gotta go they use the pad and will use it just fine from there on out (they prefer to go on land).
We have life jackets however we usually their harnesses with a teather, gives them the freedom to move about a bit more and our female thinks she is being tortured if you put any kind of clothes on them.