What gives??

So I created a Kaulen soley for the purpose of trying to raid each harbour when their is a capital ship inside of it.

So I get to December 22, 1939 and set sail for Loch Ewe as according to the ship dates and locations handy chart Jimbuna gave me the Revenge and Nelson should be moored up there. I make it there by the night of the 24th.

So I head on in, sneak in at night to find that the BB Revenge is not there.

According to the chart, they enter in November of '39 and the Revenge doesnt leave until January 5th, 1940??

A similar thing happened at Scapa, only once when I snuck in I saw two Capital ships moored there, a Revenge class, and the Hood. I didnt sink the Hood because I didnt fire more than 4 torps.

So I reloaded the patrol and tried again and walah, no battleships!

What gives?? Lol