Gunter,
Because his name was Stahmer on both passenger lists - Dietr Stahmer aboard the Amaranth 18 Jan 1865, Bremen to NY, and D Stahmer aboard the Dorrette 21 Oct 1867, Bremen To New Orleans, he should be listed as such. You do not show the correct parentage for him because you do not have the right person. Gherhard was not among his names and Stamer was not his birth surname. I provided our family history to you as a courtesy to fellow researchers. Please, either place my grt-grandfather under his correct surname or remove him from your list. Anyone researching Stamers or Stahmers will be completely thrown off by your entry.
Sincerely,
Mary