I'm familiar with the old DANFS books, I bought the whole(?) series starting in the early 1970's as they were completed. The further the books went in being published, the longer and more detailed the write-ups became. I forget which organization did it, but they transcribed the DANFS entries and they were posted on a few websites, notably NAVSOURCE. These transcriptions at times were updated by the transcribers, so weren't official. Once NHHC started to put DANFS online, they started with the original write-up and have been updating them. Navsource has been updating their DANFS entries to NHHC links.

I first met Bob Cressman at NARA, and then at NHHC on research trips there. We have helped each other out with photos I had scanned that he could use in DANFS updates or one of his historical writings. And he could point me to images that NHHC has (Bob is head of Textual Records and others are in charge of photos (formerly Chuck Haberlein), but the textual records for individual ships they have often includes photos not found in Photo Collection).

Yes I have found errors in write-ups for those ships I have researched in detail (primarily FLETCHER class). Sometime ago, a guy who dives on wrecks was trying to ID a FLETCHER sunk off San Clemente Island. It wasn't obvious or easy to find in DANFS or other references, because many target ships have been sunk there. I helped to ID via configurations and research into their fates. Researching fates of USN ships isn't easy, because Bob Cressman told me the USN doesn't track ships after they have been struck. Ships designated as targets can be "afloat" for years before being sunk. The units (Pacific and Atlantic) that utilize the targets have data, but many times the targets were the object of classified weapons testing. Anyway, in the course of this digging, I spotted a few errors for destroyers data, wrong dates for launch, commission, etc. I would forward updates to Bob as I found them to be updated in DANFS.

As Tracy said, Bob and others at NHHC have been updating the 1,000's of DANFS entries. Since Bob is a branch chief, he had others write the updated histories. One of Bob's good friends at NHHC was writing a lot of the better "new" histories. But, he died during the pandemic and Bob is writing more of them himself. This was one of the "tasks" he could do from home during the shutdown. Yes NHHC use History Reports, particularly for more recent ships (aka recent 1950's through 1970's and beyond), they use the annual history reports submitted by the ship to NHHC as a prime source. Some of these are better than others. For WWII era, documents like deck logs (NARA) and after action reports are utilized. The more famous ships get bigger write-ups and Bob has more knowledge about them.

DANFS just can't provide the total history of USN ships. But are a good thumbnail history.