Hi, there is a line in Battlefleet: Koronus for the "Shadowhunter" Eldar craftworld raider:

" Small and Agile: Due to their small size and phenomenal manoeuvrability, Shadowhunters are capable of attacking and
destroying torpedoes and attack craft. A Shadowhunter ignores penalties for firing on such targets."

I have not found rules for shooting at attack craft / Torpedoes anywhere else, but this entry suggestst that there are ("ignores usual penalties"). If there are rules for this could someone point out where they are written?

best my knowledge that was a rule they left out, but it does appear in battle fleet Gothic and i believe it is a -20 to hit. Most people seem fine using that.

Dang, and it's never been errataed?

Correct on both. You can find the closest thing we have to an official house rule here: https://community.fantasyflightgames.com/topic/45855-bfk-shooting-at-torpedoesattack-craft/?p=460816

I believe their reasoning was that aiming ship guns at something so small as to be unreliable, but I like the -20 idea.

Battlefleet Koronus, pg 12, bottom right, black box:

"A ship’s turrets work identically whether defending
against torpedoes or attack craft. Before the attacker rolls
to score hits the defending vessel may attempt a Ballistic
Skill Test using the crew’s Skill Rating, with a +5 bonus
for every point of Turret Rating the vessel has (the ship
must have a Turret rating of at least 1 to attempt this). If
successful, then the turrets hit once, plus one additional hit
for every two degrees of success, with each hit shooting
down a single torpedo or attack craft squadron, reducing
the number of torpedoes in the salvo or attack craft
squadron in the wave before the attack roll is made."

Zolik, that is for Turret fire. The OP was asking about main ship armaments, like Macrocannons and Lances. IMO, Lances should be -50 with Macrocannos being around -30. With PC stats, -20 doesn't seem to much of a hinderance. Hmm... another thing I need to include in my House Rules.

I think Zolik is saying that's how a ship CAN fire at torpedoes, attack craft, and such. They are too small, fast, and agile for your monolithic, plodding cannons to hit, especially with their half-hour? reload times, and such. Turrets ARE the way to pick off little, incoming vessels/ordnance. Since Shadowhunters are "small and agile", they have a special rule that also lets them target such things, with their rapid-firing lances, I assume they have. Eldar weapons are much superior, regarding rate of fire, and such, I assume, even without a mechanical rule for it, here.

In BFG rules allowed to fire macrocanons and lances at "small fry" (that being torps and attack craft) at a penalty, two column shifts if I recall properly. If you think about it it really makes sense, yes its harder, but as long as you have enemy vector and thurst you can use cogitator to set the angle and timing for main battery to send a wall of fire that could intercept them and hopefully obliterate enemy ordinance. Also since normal macros fire, and im citing lexicanum here, "massive and explosive shells" you could argue that a cunning RT might ask their mechanicus to rig those with special fuses beforehand, fuses that would detonate them after certain time passed in flight for a macro-flak-cannon effect, or to set debris fields on the path of incoming craft. But even without such machinations I imagine that a sudden passage of a broadside fired at you must feel like a sudden high speed flight through an asteroid field, and would be potentially dangerous. if not cathastrophic That of course if aforementioned broadside "hit" if it misses then timing was off or squadron performed a random maneuver designed for such ocassion and nothing happens.

As usuall please feel free to point out mistakes and show mercy for english is not my native language.

Check the quote from zolik, but as a followup I should note that it's possible to take penalties to such if bombers/assault boats are defended by fighter escorts. The Shadowhunter's ability basically doesn't care about such, and thus they can generally draw the attention of torpedoes or attack craft to shoot them down by moving within one VU. Plus, as an Eldar vessel with cloaking technology it's likely to give far more than it gets.