Is there such a thing as a HD portable dish for Direct TV

The reason we want an automatic HD is we now have a new HD tv at home and in the RV. Direct TV refused to set us up with a HD dish due to our living on a floating home. The river, during spring runoff to summer lows varies fifteen to twenty feet. Twice a hear it would have to be re aimed and would be a pain. I though an automatic would be the ticket but it needs to be portable so I can also use it at home. Oh yes, our cable company is not the best...