A few points to consider that US bombers vs. JPN destroyers is not really a risk for the US, as risk is a measure of likely loss vs. Likely reward.
Likelyhood of loss: Bombers attack on 4, destroyers defend on 2. In 1-on-1 encounters, JPN subs will be hit 2/3 times, while hitting on defense only 1/3 times. If the US vectors 2 bombers to 1 destroyer, this advantage tips more in US favor.
Direct cost: Assuming a 1:1 trade every attack, if the US is earning 50% more than JPN (ie: 75 vs 50 IPC) they can afford the trade, as bombers cost 50% more than destroyers ( 12 vs. 8 IPC).
Indirect cost / opportunity cost: Even with a worst case 1:1 trade, doing so preserves US subs (6 IPC each) AND allows the sub to do convoy disruptions (assume 2 IPC minimum). This makes an economic opportunity cost swing of (6+ IPC) x (# of US subs on station).
So, is a 1 US bomber per turn loss (worst case 12 IPC) that enables subs to max convoy SZ 6 and SZ 19, in addition to sinking a JPN destroyer every turn (>24IPC JPN loss per turn) still as risky as it looks on the surface?





