First off, nothing bad towards the name, the Hellfish as you call it is mostly called Blenderfish for some reason.
So. Let's get on with it.
How do I know I am in range for the Hellhound? I can't see the projectiles, how do I know if a shot was effective or if i should have waited a second longer?
It's hard to know when you are in range, so that is just something you have to practice lots and lots with.
Shoot one, hit or not hit? Check map for range. Shoot again, okay hit. Check map and you know what the range is. So that is just trial and error.
The difference between Hwach/carronade is what job you want done.
Long range heavy disable on components? Hwacha.
Close range killing power/Disable? Carronade.
About side guns, I agree that one side should carry an artemis for easier sniping of the enemy guns so that's good.
On the other side I could argue about a mortar to get the explosive damage available once you strip the hull with your carronade, turn a bit and just blow them to bits and pieces.
Team setupPilot: I don't run blenderfish that much anymore, and when I did kerosene was still phoenix claw equivalent but these are what I would pick now prob:
Kerosene, Tar and Claw.
Kerosene: get there faster.
Tar: Give them additional hell.
Claw: If you charge an enemy but don't want to ram, you pass close, max reverse and claw for max turning power and can be on them faster than they on you.
About engineers, I'd prob run one buffgineer with pipe, buff and extinguisher and one main engineer with a standard loadout.
Gunner should bring pipe and for round lochnagar, charged/heavy and incendiary/heavy. Why? I'll tell:
Lochnagar: Insane damage, and even more with buff on it.
Charged: Nice amounts of damage.
Heavy: Pinpoint those components mate, reduces spread a lot.
Incendiary: Grants a lot of fire stacks on hull/balloon. Source have told be about 10 stacks of fire per shot with Incendiary loaded.
Tactics.This obviously depends a lot on the map and on what other ship you have as well as what ships you are facing.
Mostly you want to take out one of the enemy ship's balloon to take him out of fighting and then focus down the other ship, turning back to the 1st after that.
Or you can be that annoying bastard that sits on the enemy pinning his hull/balloon while driving the enemy to the ground killing him off that way.
Although, that requires your ally to be good enough to be able to finish off the other ship on his own.
Say for example a friendly pyra is engaging an enemy ship, both are far away. Can a single artemis help enough to justify staying away, or should I rather speed to help up close?
There are many variables to be taken in here. Some are:
Is your ally damaged and about to die?
Do you know where to enemy ship is?
Depending on the answer to those questions you decide whether or not going in is wise or not.
So, how can I smartly approach other ships?
This one is hard...
Most ships are exposed to their back, so try to get there, is what I would suggest.
It's a hard question, and the best thing is to just practice and learn by yourself how to handle the different ships.
That's about it from me.
Good luck out there.