From: US Midwest
I tried a variation of the usual Sealion strategy in my current game against Fafnir.
My first purchase with the Germans was 2 pips of amphibious tech. As soon as I got the 1st one, I purchased a 3rd to get amphibs 2 as soon as possible. I attacked France in Spring '40 as usual, and took it about the usual amount of time. Nothing looks suspicious at all.
After France fell, Fafnir did what Fafnir does, and sent everything to the Med to wipe out the Italians early. In addition, he also did a side invasion of Norway, stretching his resources to the limit. At this point, I knew the UK had to be empty, as I had anticipated.
In early October, I got amphibs 2. This gave me 4 amphibious ships and 2 long range amphibious ships, in addition to my 2 para units. 8 units on the first turn makes for a devastating Sealion. It also gives you enough units to proceed with taking the rest of the UK without having to wait for a port to get to 5, and offering his navy a chance to stop you. Against a largely abandoned UK, I think Manchester could be taken in 4-5 turns by this force. You wouldn't even have to delay Barbarossa.
To make a long story short, I took London easily. Unfortunately, during the turn they were in the assault ships, Fafnir managed to use his maritime bomber to somehow pick my HQ out of a large group of ships and damage it. He used aircraft to kill it the turn it landed, and with out the HQ, the invasion ultimately floundered. If not for that bit of bad luck, it would have worked.
And even in failure, the invasion was highly useful, as he had to move all his navy and troops back to the UK to retake it. This set his plans back a long way, and if you can get Fafnir to change his plans, that is about as close to a victory as you are going to get.
A late Sealion with amphibs 2 is absolutely a viable strategy. If it can be done to Fafnir, it can be done to anyone. Watch out, you UK abandoners! You have been warned.
Lock up your wife and children now,
it's time to wield the blade...