Thank you all for your encouragement and the constructive feedback!
Yes, I had a lot of fun doing it - so far 2 afternoons and one evening, most of it spent on:
- figuring out what I want to achieve
- getting image sizes and resolution about right
- finding the directories and files in SH3 for ship data and images
- editing the images (both museum screenshots and in-game .tga files)
- learning a bit more about InDesign to create the document
Actually, once the document structure and base images were all prepared, the creation of the documents proper did not take long at all.
@mrbannon: Not a stupid question at all

There are no updates. The in-game recognition manual is the opposite of realism in that respect: instead of not having the latest enemy ship types, the manual has ship types that aren't even in service yet.
@Gustav: ah yes, I see your point. Initially, my only goal was to better be able to identify the ship and then find it in the in-game manual. As I still rely on the weapons officer to identify the target for me, it is quite easy to click on the type and get the correct page for height, length and draft.
When that weapons officer assistance will be gone, I guess I'd be back to frantically flipping pages ... Ugh. Thanks for telling me now before I add more ships! I'll make an update that includes height, LoA, beam and draft in the document and - while I'm at it - copy the required data directly (well, almost directly) from the cfg files into the document. That should reduce the probability for human error (that's me: the human error element) considerably.
@Gustav, Karl Heinrich and GoldenRivet: I've seen some of your work and that of quite a few others, too. I guess it's as much the fun in doing it as it is the result that makes me do it. Can't remember them all but I really liked one recognition manual, done by Canovaro - it showed the in-game manual pages but with target areas highlighted. Very nice, unfortunately my ship types are different and the renown is different, too.
BTW, does anybody know how to translate the numbers in the [2D compartments] section of the cfg file into coordinates?
Then there was one that was completely different: drawings instead of photo or the in-game manual pages (can't remember by whom, IIRC it had German ship types), also very nice.
I know that I need something like a photo for a quick shortlist, but then the fine details in the recognition manual are good, too. And the 'angle' views.
On a patrol, before I spend a torpedo I really like to know what it'll earn me in terms of renown. So, that had to go into my "do it yourself" as well.
Armaments would have been nice, too. But too complex, too much text and changing too fast. I don't want to include from-to dates ...
Good Hunting,
Helmut