I have been experimenting with these BC CV killer fleets and so far I have not managed to sink a single carrier. Granted I shoot their escorts down like flies and anything that is not a carrier is fast on the ocean floor. I think my mistake was that I did put armor on them so I guess they are too slow to catch up.
Now I am going to try the same tactic with Pocket Battleships, surely they will be fast enough
Don't bother testing that - i already did it with CA/CL and you still don't catch carriers unless you get lucky - the way to test this is to have pause on battle start and check distances of ships, if carriers start 55km away it doesn't take rocket scientist to realize that you need ~30km/h speed to catch up with 24km/h+ carrier fleet and still arrive above surface. Now when you "surprise" carriers once in a while - you are shooting at start already.
Air cover changes that equation in favor of the BBs because NAVs and CAS will inflict real damage on the CVs whether or not the BBs ever get in range. But without being able to pin them in a pitched sea battle, the NAVs and CAS won't be able to get more one or two missions against the CVs. Pinning them down means you can give them love from your NAVs over and over again.
I am aware of this bait tactic, actually i was always big proponent of using BBs + CLs in this role ( instead of BCs/CAs or DD screens ), as they can take punishment without loosing zounds of IC days in unlucky battle, speed doesn't matter when NAVs do damage and all you need to pin enemy fleets and survive long enough.
Actually in some other thread Alex proposed (or rather shared) tactic of using massive CA+CL to shred CAGs with massed AA - but again, that didn't work for me either, increase in AA attack is not that huge and CAs tend to sink too much for my taste.
With INT supressing RAF bases and helping in seas and with NAVs attacking pinned ships - you can damage RN with NAVs quite a bit, sinking old ships and stuff - results are worse if RN packs ships into larger fleet (due to AA and more targets). Quite a few kills will be probably in ports on damaged ships and the rest in lucky raids with that 75% surprise mod.
But if you don't execute Sea Lion, ~1941-42 time frame, modern RN and USN fleets make NAV tactic useless ( think about it as the end of SS domination once modern ASW and CTF fleets come online).
1) Size - they tend to be larger
2) Modern ships have AA that tears NAVs apart fast and (wild speculation) ship/land radar prevents surprise bonuses.
3) NAVs simply don't scale well due to stacking limits.
If the BBs have enough of a speed advantage over the CTF, it can also kill screens. That isn't too exciting, but if the CVs have no screens, then putting them out at sea can be dangerous if they run into the SAG again.
My findings in this department are a bit anecdotical, but consider the following, in my GER games i run the following ships for 1939 summer crusade against RN:
1) Main CTF of 6xTech V(m1938) carriers + 6 initial starting CLs as screens with small ship radar and AA upgraded. Speed is 24kph
2) Auxiliary CTF of 4x escort carriers of tech V without any escorts, tho I sometimes attach starting CAs for shore bomb values. Speed is 20kph
3) Writeoff CTF of 6x escort carriers of tech I without any escorts. Speed is 18kph.
With (3) in combat funny things happen:
1) If engaged by small SAG - ships start @ 50km distance, my fleet has 95% positioning with skill 4 commander and when i get pause screen, some of enemy ships are already deorged, 6 CAGs are no joke. Still enemy will close in but most of the time will simply have to retreat due to damage - I will pursue them into next sea zone (ofc avoiding nasty sea zones)
2) If engaged by large SAG - ships start @ 50km distance, but i have to retreat immediately and my ships run to port with minor damage.
3) If engaged by CTF - my ships take damage and when battle starts both sides are "damaged", but i can't force a retreat on enemy unless it is a small CTF and will need repairs in ports. ( i guess it has to do with funny sea attack/def values
)
With (2) fleet it is the same, with a twist that large SAGs are less dangerous as they don't close in so fast.
So as you can see, technically screens don't do anything to CTF performance as long as you have good positioning and play cards right, their role lies solely in AA damage, AA defence values and presenting more targets to opponent air power.
P.S. And don't panic if you see a big nasty BB in "shooting" mode against your CTF once game is paused - check it's target and most of the time you will see that it is shooting own ships
Real suprise battles start with your carriers close and getting torn.