@Trooper51:
I have another question. It is round 2 and Russia is not at war. Russia moves sub from sz 127 to sz 112. On UK’s turn they move a lone destroyer to sz 112. Germany has their navy in sz 113. UK hasn’t any navy in the Atlantic, other than the lone destroyer. My question is, can Germany just attack the UK destroyer and not upset the Russian neutrality?
Yes, Germany can attack the UK destroyer and ignore the Russian sub.
At sea, you can ignore units of powers with which you are not at war, and you can attack units in the same sea zones belonging to powers with whom you are at war.
It’s on land that you must declare war on all powers that have units in the territory you are attacking.