Thanks Siarra for the precisions.
All this talk about anchor use is quite interesting. I think this is probably why, on later types XXI and XXIII they didn't built anchors at all.
A personal reflexion too, is that in time of war, if the anchor is dropped and suddenly the skies become very unfriendly, you will waste very precious time recuperating it. Even if you want to abandon it to go faster, time to release the chain will be probably too long too.
Their operational territory also didn't really provided them with safe places to anchor.
Conclusion, it seems logical to paint the whole place as if it is never used.
Now I ask myself, even if the anchor is never used, doesn't the chain wheel and these two holes produce some small rust streaks just as a lot of other parts that do not move does?
The truth is they build these anchors to give future modelers headaches... and something to talk about. Maybe they had foreseen the use of forums to sort them out too!!!!!!!