Subs/Destroyers/Bombers and you!

You are right.  Bringing destroyers makes your bomber hits possibly go against subs.  It seems counter productive but only for the first round of firing.  You can take the first round of defensive hits on your destroyers making the sub stealthy again and imune to bomber hits.

The best fodder IMHO in this type of battle you described would be fighters to take along side of your bombers.  Defending subs couldn’t be hit by aircarft and couldn’t fire either.  Thus taking the subs out of the battle all together.

I ran this through a simulator and if your only goal is to kill the BBs, your are better off not bringing the DDs - even if you don’t replace them with something else.  Replacing 2 dds with 2 subs (saving 4ipcs as well) makes it a significant improvement.  Just keep in mind, in the first two cases I was not looking at your own losses or net IPCs etc…  The DDs do provide you fodder to protect your more valuable units.  I was strictly looking at a 100% BB kill rate.

Attacking force / Approx likelihood of killing all 4 BBs
5 bom, 1 CA, 2 Sub, 2 DD / ~67%
5 bom, 1 CA, 2 Sub, 0 DD / ~71%
5 bom, 1 CA, 4 sub, 0 DD / ~96%

@TimTheEnchanter:

I ran this through a simulator and if your only goal is to kill the BBs, your are better off not bringing the DDs - even if you don’t replace them with something else.  Replacing 2 dds with 2 subs (saving 4ipcs as well) makes it a significant improvement.  Just keep in mind, in the first two cases I was not looking at your own losses or net IPCs etc…  The DDs do provide you fodder to protect your more valuable units.  I was strictly looking at a 100% BB kill rate.

Attacking force / Approx likelihood of killing all 4 BBs
5 bom, 1 CA, 2 Sub, 2 DD / ~67%
5 bom, 1 CA, 2 Sub, 0 DD / ~71%
5 bom, 1 CA, 4 sub, 0 DD / ~96%

Except the hits can be taken by defending subs as well.  If you attack a fleet of 4 BB and a 4 sub you are better off with 5 bomber and 3 fighters.  The task force will have cost you six less IPC and has a 96.6% chance of winning against 4 BB while ignoring the 4 sub.

The probability you listed don’e acount for 4 sub present defending.  The odds for:

5 bom, 1 CA, 4 sub, 0 DD against 4 BB and 4 sub is less then 7%.

Oh, I’m not saying I proposed the perfect attack force.  Certainly if you ONLY care about the BBs and not the subs, an ALL airforce attack force would be best.  I just took the OP’s germany attack force and modulated it as he suggested - first removing the DDs (which as I expected gave him a slight improvement) and then replacing them with additional subs as he described.

when you say ‘5 bom, 1 CA, 4 sub, 0 DD against 4 BB and 4 sub is less then 7%.’ I’m not sure what you’re saying or where you get that from.  The sim I used said it would be about 9% to clear the zone completely and only about 4% possiblity that any of the BB’s survive.  Maybe I’m doing something wrong, or the Sim I’m using is buggy with its order of loss.  :?  Any hits from the fodder boats (CA, 4 Sub) would be taken first against the subs, but once those fodder boats are gone, or the subs are gone, it’s bombers against BBs. and most times it seems the Bombers should win out.

Now that I think about it, the one thing that may not be factored into the sim is that it would make sense for the defender to take any boat hit against the defending subs.  The sim probably automatically assigns the first 4 hits to damage the BBs even if they come from other boats, which would be sub-optimal, given the bombers can ONLY hit the BBs, so you want to direct any non-Bomber hits to the subs.  I guess it would take a pretty clever sim to really get good numbers on this.  :|