What determines which ship in a fleet gets targeted?

Yes, the more guns a ship has, the more likely it is to be targeted.  End-game weapons can significantly affect the targeting priority for a ship.

The more defences and hitpoints a ship has, the less likely it is to be targeted.

Fleet modules increase the chance of a ship being targeted, but if a ship has no weapons it won't be targeted until all the ships with weapons have been wiped out.

The solution here is to not fit out your BBs with full weaponry.  The cheapest option is to just leave some empty space in the hull.  Yes, it is somewhat wasteful, but if you don't need to use the space to win a fight then you might as well save yourself some maintenance.

Ah, thanks! 

Yes my BBs did indeed have black hole guns, and lots of them.

Another thing:

Here is the exact formula for the threat value:  (Attack / [Defense+HP]) (not so sure where does fleet modules gets fit in but I think it will multiply the attack value by a very large amount).

Highest gets beaten up first!

Thanks!

Emm, UE on challenging seems to base priority on attack / hp, maybe taking defenses as secondary factor. My fleet consisted three ships: huge Lure (att 490 def 861 hp 163) large Gunship (att 673 def 0 hp 294) and medium unarmed Sun Tzu support ship and in all combat simulations the Lure was the priority target. (In fact the Gunship was designed to have lower att / hp rate.) (Don't ask about the figures, they are at least twice the value of those of the shipyard drawing board - military resources and such.)

Maybe the AI should be improved to consider chance to actually cause damage (for example the Yor heavy fighters  most numeruous in the "target fleet" with attack 88 had practically no chance of damaging the Lure, neither their Dreadnought with attack 176 for that matter). For example for each of own ships for each enemy ships separately:

1, Deduct enemy defense from own attack (if negative set priority to zero and skip the rest of the steps - your only hope against that ship is pure luck)

2, Divide it by the actual hp of the enemy ship

3, Multiply it by the attack of the enemy ship minus defense of own ship

4, Multiply it by the actual hp of own ship

Then sum up, the enemy ship with the highets value wins the prize of being tageted first. But there is no upper limit on complexity ie assigning targets separately for different weapon types and so on ...

antibor, while your example does not fit with the above formula (and therefore one of them must be modified), it seems you don't understand how defenses work.  This is understandable, as it changed from DL to DA.

The AI-or the targeting AI-should not consider its ships worthless because while each ship may only have 88 attack against even a hypothetical 880 defense ship, due to defense depletion (on a per-round basis only), 11 such ships have the aggregate firepower necessary on a purely one-to-one ratio.

Granted, a one-to-one ratio, particularly given multiple ship spreads and therefore the attrition that will no doubt occur, is likely insufficient, but simply because a single ship is ineffective by itself does not necessarily mean that a 5- or 10-strong fleet of said ships is.

What you appear to be suggesting is that the targeting mechanism choose the single ship which has the greatest chance of destroying it first-but it's easy to concoct scenarios in which a large, heavily armed battleship is used as support to flank a number of smaller fighters, with larger aggregate firepower as well as potentially more flexibility in targets.

That is, while it might be interesting to have the targeting mechanism employ that algorithm, it would not always be ideal; there are plenty of instances where, rather than the largest threat, the easiest-destroyed threat will prolong your own survival.  And having the targeting AI differentiate between these two would be a nightmare.

One of the nice side effects of the way that things work is that your transports and support ships are always targeted last-presumbly because even if the pilots of the enemy ships were attempting to target them, your other ships would attempt to intercept and provide cover fire.  But as they are among the easiest to destroy, if not the easiest by far, and particularly since the combat modules in TA can have a rather large effect on a battle, easily causing it to swing the other way if the ship in question were lost, it would play hell with the easiest-destroyed-threat option.

Sole Soul, Thank you for the correction. I really forgot defense attrition (within turn) so upon your comment I attacked with only a large ship (with 502 defense) and it got seriously damaged. So my idea about improving the AI was wrong.

Now I am not sure about my claim regarding the targeting priority either as I made a test with an armed freighter and it was not targeted.

Actually I have found that it is impossible to base fleets on a typical DBB/BB/C/DD system because of the overwhelming power of black hole guns, nightmare torpedoes, and doom rays once technology reaches maximum for both parties.

I've just been using fleets of two support ships + all the same large hull armed-to-the-teeth, fast ship, losing one each battle, makes things easier, if less convenient. I was finding that even the most armored DBB tank ship was still getting blown away by the 1000+ attack power enemy fleets. And that's with as many defensive buffs as possible.

Two questions:

(1) As a person who knows very little about the navy (or military in general) what is a "DD/CL/CA/BB/DBB style system"?  What do they stand for?  And what do designations like "Cruiser" and "Battleship" mean?

(2) The above conversation seems to imply that if you go into battle with a fleet of identical ships the damage will be roughly spread evenly across your entire fleet.  Is this generally beneficial?  It seems like you'd come out of a battle with less ships lost...

Losing only one? How can you lose only one attack only ship against 1000+ attack enemy fleets without the first strike (maybe super warrior?) ability?

It means destroyer, light cruiser, heavy cruiser, battleship, dreadnought. It's just nautical designations for ship sizes/roles. 

Antibor: it varies greatly between battles. Generally the ships are expendable.