Slitherine

Yes, an Allied blob, and I created it myself to protect against Sealion. The trick is building nothing but subs, not even researching until you have built four, giving yourself 5 in the north and one in the Med. Anyway, the point is that you can totally hem in the German Surface fleets until they are hopefully able to bomb you out after finding you the hard way. Not very historical since subs never stoipped anything from moving unless they sank it.

However, in blocking egress from Hamburg, you also fill up all of the available exit hexes for the Kiel Canal. Don't know how I really feel about this...but it's a nasty way of doing your opponent dirty if he doesn't move on Norway before you get a couple of subs out there.

Sounds like it would give the German planes something to do!
I dont see a big issue with this as there are quite a few downsides for the british in doing this. Its up to the axis player to exploit them...

That is not a problem. The Germans can send air units to the area and attack the subs and if Britain builds nothing but subs they will suffer later in the game.

If this prevents Germany from taking Norway it's a small price to pay for letting Britain sit with lots of useless units they can't use to bombard German units or land in France.

Norway can still be taken with Airborne+TACs if absolutely necessary, it just takes a bit more time. Of course if UK manages to bring ground forces the para alone won't be enough and reinforcing will be hard.

Still IMO, this's a good idea only if Germans go for Sealion. Otherwise those subs won't be very useful way to spend UKs limited PPs.

If you build and research nothing but subs you already cripple GB yourself, german played really don't need any further effort in this direction (like sealion) and he should do other stuff.

not so easy to take Norway with TAC's and Para's now though - but I would love Brioatin adopting teh Sub blob if I was the axis,as others have said, it cripples them