Does anyone know what exactly is being gained by ships with experience?

I noticed this between Rookie and Rookie II:

You get a lot more health (+266 which is 48% more).

You get more defence (+13 which is 14% more).

But is that defence against lasers / balistics? How does that apply in combat?

Health does seem to increase with experience. I've noticed that building 'Big Data Shipyards' means newly built UE battleships start with ~4000 hp as opposed to a rookie's ~2300. What gets confusing is health also seems to be determined by the era in which the ship is built. I've loaded a pre-patch late game save and noticed some more-experienced ships were having less health than newer ones. Another time was when my 5 Era I corvettes with 495 health lost to 2 corvettes with ~1200 hp each which I presume were experienced and built in Era II.

With each Era there is a notification saying "Hulls cost 50% more industry".

So I thinkg that translates into more health also.

But still the system is a little mystery to me.

Would be nice to have a reference point on how it all works.

Hi,

You earn health points for each level up, and the defensive power stat (the shield icon) takes in account the health of the hull.

Each new era increases the initial level of the ship you build, that's why the hull is more expensive and you see an health bonus.
We will improve the feedback in the ship design and tech tree screens to explain that!

I had an idea about automating the bestowal of a trait to accompany ships' leveling up.

My idea was to boost more than just HP with a level up (which honestly doesn't even make much sense.)  A hull is a hull is a hull.

I suppose that crews get better at making repairs on the fly, but I think the real goldmine immersion-, and intimacy-wise, is to actually grant bonuses to a variety of stats, that depend on a choice you can make to the templates in the ship design.

https://www.games2gether.com/endless-space-2/ideas/42-traits-4-veteran-ships-select-priority-by-template

Check out my ideas above, add your suggestions for names, and upvote to see a more detailed and personalized fleet experience!