This wasn't such a bother until ARM mission 7, "the Defence of Larab Harbor". Facing battleships and missile ships that have WAY greater weapon range than sight range... it feels like the AI units have weapon range = to sight range, while all my units are limited to just their pitiful sight range, UNLESS they are the target, then it seems ONLY that unit will retaliate into the fog of war!! In combination with the high cost and time of naval units (+ the epic slowness of tier 2 ships), and the scarcity of metal on this mission, this feels awful. :(

I find myself being annoyed by this system of small sight range for every unit, and variable weapon range. Yes I see that it induces aggression... but with the AI seemingly following totally different rules this seems very lame. :(

Any tips? I'm playing on hard... I want some challenge, but I'm feeling violated by this!

The hard AI is cheating, better use medium AI.

I suppose I will have to try medium. TY:)

Reading around about this issue (mostly on tauniverse.com) I see what seems to be conflicting info. Some state unequivocally that the AI needs visual confirmation to fire, or a Targeting Facility, on any difficulty. In my experience this is NOT the case!!! Though most of the discussion relates to skirmish AI... perhaps the campaign AI is different.

It's tough on hard, that's for sure. It is do-able though, it's been a long time since i've played it on hard but the key thing on this mission is the use of submarines instead of trying to build ships. Submarines can annihilate any type of ship, especially missile ships. From what I remember, I built a KBot lab to churn out Rockos and Jethros to take out any Enforcer ships that were foolish enough to try and come too close to my base, moving the ranger as far north as possible so as to save it from bombardment.

Instead of building Crusader ships, I think I built a handful of construction ships, scout ships, and as many submarines as I could, trying to build up tidal generators so i could build some metal makers for desperate times. Not only will the enemy send ships but they will also send amphibious tanks so the submarines are an absolute necessity.

You will be hard pinched for metal on this mission, so try and reclaim as much metal as you can from ship wrecks when safe to do so, build a few sonar stations around the harbour for early warnings of naval attacks. Remember, a group of submarines can obliterate enemy ships if you get the drop on them with scout ships as bait. Battleships have no defence at all against submarines as well so keep that in mind.

Jethros or samsons at the moho mine are also crucial to take down any aerial threats including bombers to stop them from destroying it, scout ships can somewhat help but don't rely on them too much.

Sorry for the very long reply, but in summary, this mission is impossible if you try and build ships to outgun the enemy as they have a much much bigger fleet, with proper use of multiple saves and resource management you will be able to win it. Reclaiming metal from big ships almost guarantees a win.

It gets a bit finnicky, but you can use manual radar targeting to tell your units to aim outside their sight range.
Select unit, click attack and then select a red dot on the minimap.

I am sooo stuck on this mission its super annoying. The enemy AI has ridiculous range through the FOW. Gonna try and build subs and see what I can do. Ultra annoying.