Four and five years ago, when I was researching my Dutch and Frisian ancestry and creating family history pages on these lines for my personal genealogy website, I came across a website that was invaluable: the "unofficial" Holland-America Line website, originally located at http://www.unofficial.net/hal/. The term "unofficial" was used, because the Holland-America Line is still very much a viable passenger ship company with its official website located here.
This comprehensive site was vital for researching the ships on which my Dutch and Frisian ancestors immigrated. Filled with photographs and paintings of the many ships of the H-A Line, along with the history of each ship and occasional information on the captains and crews, it gave me background for the history of each of my immigrant families. You can see how I used this information on my TUINSTRA and DeVRIES pages (caution: I have not yet updated the links on the pages).
Then several years ago, Hans Segboer the webmaster, closed the site due to not being able to maintain it. It was a great loss to the Dutch-American genealogical and historical community. I am happy to report that last week I discovered that it has reopened at the URL http://www.halpostcards.com/unofficial/.
I'm very excited to see that the site is back up. Since it went down, I discovered more names of ships on which my immigrant ancestors sailed. I look forward to using "Unofficial HAL" to do expand my research on these Dutch families!
If you had ancestors who immigrated from the Netherlands, or from other European countries via a Netherlands port such as Rotterdam, be sure to check out this fascinating and informative website!