Thank You for your help on this and information. You mention the building of the bridge over the rhine and that makes me think even more that this may have been his unit,because my dad told me that he remembers Grandpa saying that he fell of the bridge and floated down the Rhine.
And so far i have only found one site on the 51st. And that was what had me thinking that may have been his unit because of the time and place. But as i have said im not sure. If you could please either post here or email me some of the other links on the 51. i would greatly appreciated.