Hi, Have you considered that your Grandfather did not intentionally falsify any informaton - voyage coule be easily traced. It is possible-that he just had the Port of Departure wrong -so easy to do.
How long after his arrival - did your grandfathr apply for Naturalization.
Have you checked the passenger list for the Neuw Amsterdam
It is also quite possible that your Grandfather - had the name of the ship wrong !!!
*I have researched a family - connected to ours - who insist that their family arrived on the Lusitania *** before the ship was built. That information is in their published family history - and claim that the passenger list -for another ship is incorrect.

What is your Grandfathers name ?

Cheers & Good Luck, Stella