Does the war influence convoys

[BettingUrlife]

Just wondering if the war influences convoys and their routes. For example I've seen convoys travel the US/Canada to UK route many times right from the start of the war (i.e. 1939). But do the UK to Russia convoys start in 1941 (i.e. according to history (I'm guessing they started some time in 1941)) or right from the start (i.e. 1939, I mean this as a result of a bug)? Same question for the African convoys too. I've never really hunted the Russian or African convoy routes (only seen maybe a dozen or so in all my campaigns) so I can't answer my own question yet.

Also as the war situation changes do the convoys change? E.g. The African campaign quietens down from 1943 but heats up in Italy of course. Just to explain a little further, I really enjoy hunting the N America to England routes but (in my campaigns usually) the first 6 months of 1942 seems rarely bare, very few convoys. So, is it just 1) my bad luck; 2) convoys are being sent elsewhere?

P.S. probably not a well-written post but I'm tired