Q1 Was the document a .doc file? or a .odt file? The question is important because Writer handles the two types of files differently. .odt is better than .doc for file recovery purposes.
Q2 Did you have AutoSave switched on? (Tools > Options > Load/Save > General > Set how many minutes between AutoSaves)
Q3 Did you have Always create a backup copy enabled? (Tools > Options > Load/Save > General > Always create a backup copy)

- Save options
I think that the "file full of #" or "file full of zeros" means that Writer reserved the space to write the file, but Writer was prevented from writing the file. So all you get is the # or the zeros, and no content can be recovered. In this case, if you want to get back data, you need to try to find and un-delete any temporary files created by Writer.
In fact, a .doc file is a zip file, and it can be unzipped. But, as Hagar says, the file
WordDocument inside the .doc is a binary format, so it is difficult to read.

- .doc file unzipped
The contents of
WordDocument look like this when opened in a Hex (binary) editor - this is HxD from
http://mh-nexus.de/en/

- WordDocument from .doc file viewed in HxD - note text on right side
Incidentally,[b] never save your work in .doc files (or any other format apart from .odt). If you are absolutely forced to produce a .doc file, then work in and save your work in .odt, and only create a copy as a .doc file at the very end. Why? Because .odt supports all of Writer's features and other file formats may not. That is why Writer warns you when you try to save in another format.[/b]