I am not sure why I have not come across this website before: http://www.shipindex.org
It is the most comprehensive listing for vessels on the internet. The search engine allows you to enter a ship's name and give you a result consisting of different sources for that vessel. In my case, I was researching a brig I knew had been built in Bath, Maine circa 1820-1840.
The search results produced a list of sources, and referred to various ships, all of that same name, built at various times - in various places. You can easily sort through the list of results if you possess either the approximate dates the ship was built or in service - or the general location of it's service.
One of the results: "A Maritime History of Bath Maine and the Kennebec River Region," by William Avery Baker, clued me in that this particular ship was the one of interest to me. The website results go so far as to list every page contained within that volume, that refers to the ship in question. What an enormous help!
They have many more offerings, and a wide variety of types of resources (magazines, books, CD's etc.) But I will let you read more about that by going to their site.
Here is a short introduction, in their words, about the website:
We have over 140,000 entries that are freely accessible, without subscribing or logging in anywhere. For $8 per month, you'll soon have access to well over two million additional citations, from hundreds of different resources -- books, magazines, CD-ROMs, websites, online databases, and more. Not only would it take hundreds of hours to search every resource here by hand, it's simply not possible: no single library has all of the resources included in this database. The time you'll save, searching hundreds of resources in just a few moments, is well worth the cost of two coffees and muffins."
Check them out: http://www.shipindex.org