This multi-volume encyclopedia of all the named ships of the United States Navy. Later volumes were expanded to include smaller vessels with numbers like LSTs, PT boats, and harbor tugs.
The entries include details of armament if any and important campaigns that the vessel took part in. The ships that took part in World War Two are especially well covered. If you had an ancestor who served in a ship of the US Navy; you are likely to find it there.
The books are available on a web site of their own; the most recent ships are covered in another web site of the US Navy of today.