Why even famous warships still have undocumented details

Are there ships for which historians still do not have enough information?

Nearly all of them; even Warspite's rebuild contains details left to yard judgment that surviving plans do not settle.

The panel answers that no warship is documented as completely as a serious researcher would like. Even Warspite, one of the Royal Navy's best-studied capital ships, retains disputed details about how armor and other features were arranged during reconstruction. Surviving drawings sometimes delegate the final solution to whatever the yard judged feasible instead of recording the executed detail. Historians must therefore distinguish an approved design from the structure workers actually built and remain explicit about gaps in the archival record.