Yup, it's an experience level counter of sorts. It increases as a ship survives combat. It seems that the amount of experience gained is based on the ease of the combat. I've had medium hulled ships apparently getting no experience killing unarmed enemies and tiny fighters getting loads. The more powerful your ship is (possibly determined by cost) the harder it is to get experience it would appear. I suspect this by seeing the experience gauge falling when I upgraded some fighters. The primary benefit seems to be that more experienced ships gain additional hit points. I haven't noticed if they gain attack or defence bonuses as well. It pays to allow your ships to repair between combats to slowly accumulate experience.

all ships can have weapons

I just tried that in DA v1.5x (apparently) and although my survey ship got at least 3 messages about getting ships' logs and 'will be much more lethal once upgraded' it was still a level 0 ship with no experience once I upgraded it. Had I gone overboard by giving it 5 x laser V thus reducing the apparent experience ?

I've heard of upgrading the ship to same type inorder to "emergency repair" it. Does this affect ship experience?

How come my precursor rangers have 100 plus hit points, but if I upgrade them the hit points drop back down to 77? In my current game I have 54 precursors out of 88 ships. I decided to upgrade them by adding an advanced troop transport module to all my precursor rangers. After the upgrade their hit points dropped to 77 each.

In many of my games ship level wasn’t very critical since all it did was increase hit points, and not that much either.

However, in my last game the AI seemed to be stuck technologically. There was no incentive for me to upgrade my weapons, so I had medium hull ships running around as my primary ships with 12/0/0 attack and 0/6/0 defense the whole game (7+ years). Many of the battles were somewhat even, and by the end I had quite a few med hulls that were Level 50 to 71 and with HPs that ranged from 70 to 112! I’d never seen this before, and it was extraordinary since Level 0 cruisers generally had ~24 HPs. One ship had as many HPs as a whole fleet (logistics 25)! The only thing I can think of is that, as mentioned above, your ships get more XPs when the attacks are more even (e.g. – harder), which was true in this case. Also, I only lost 1 med hull the whole game so the more experienced ships survived. Normally I try to build uber ships so that combat is a cakewalk, but in this case I was trying to draw out the game to get a diplomatic victory with tech trading off (note that I never was able to get the diplo victory – the AI simply refused to research Alliance and I gave up).

Hydro

you can get Precursor ships? is this a download of some sort?

Precursor ships are one of the Super Events that you can get. I don't know which since I generally play with SE off but it's from one of the anomalies that you can explore early in the game. As for the level of the ship my last game it actually proved quite important. Mainly because I was using only 3 main fleets and swapping out any damaged ship the ships that survived got really high HP values. And when the Yor finally started packing some punch (first was doing about 14 mass damage while sitting in a planet and near the end of the war 21 mass) it was almost exclusively only my small ships (which had around 30HP at that point) and my vet Medium ships (HP around 50) that were really managing to not be destroyed their first fight, even with my newer ships packing some defenses to counter this.

If nothing else if you have two fleets of relatively equal power (or you having even less damage) the one with the most HP is the most likely to win, to an extent.

ok, thanks.