AU mod: Balancing Naval Bombardment

[alexman]

The Problem

Like Ground Bombardment, Naval Bombardment has also been changed in C3C to target units before city improvements and population. Like Walls against land units, Coastal fortresses provide a first line of defense for a city against naval units.

The problem is that except for the rare case of a combined ground assault with naval bombardment, or until the advent of Amphibious Warfare, cities are relatively safe from naval bombardment because units absorb the hits (but can’t get killed), which save the city improvements. There is little motivation to build Coastal Fortresses, which easily get destroyed anyway, especially with the C3C 50% increase of the bombard strength of Ironclads and Frigates (5 Frigate attacks will destroy a Coastal Fortresses 80% of the time, and 5 Ironclads will destroy it 94% of the time).

A secondary problem with naval bombardment is that the C3C AI prefers to bombard cities instead of resources, even when it doesn’t follow up with ground or amphibious attacks. The units bombarded by the AI heal in the next turn, often resulting in no damage suffered by the bombarded civilization (unless it was silly enough to build a coastal fortress in that city!).

Clearly, Coastal Fortresses do not currently serve their purpose of protecting a city from naval bombardment, especially since it’s so easy to avoid the shots from their ZOC. They are definitely the least often built city improvement in Civ3, even by the AI.

Possible Solution

Quadruple the naval bombardment defense of the Coastal Fortress from 8 to 32. A Frigate attack would then have just 9% chance to destroy it (5 of them would have a 36% chance), and an Ironclad would have a 16% chance (58% for 5 of them).

A stronger coastal fortress may also solve the naval targeting problem of the AI. Ideally, it may discourage attacks on cities, forcing the AI to instead bombard improvements as in PTW. (The AI already knows which cities have a coastal fortress, as evidenced by its ability to avoid ZOC shots). At the very least, stronger fortresses will encourage players to build them, so the AI will have finally something to destroy when bombarding cities!

There are at least two problems that need to be solved if this change is implemented. First of all, the AI needs to know to build coastal fortresses, otherwise it will not take advantage of its new strength (I don’t believe that the AI currently builds them, just as it doesn’t build walls). This is easily solved by giving it the ability to produce veteran units, for example. Harbors would also retain this ability, of course.

Secondly, coastal fortresses should probably lose some of their effectiveness in the modern age, at least against Battleships. This is a realism consideration so it shouldn’t be very important to the AU mod, but perhaps battleships should have their bombard strength increased from their current value of 8 (12?). On the other hand, if you imagine that coastal fortresses become modernized with time, maybe it’s not necessary to make them obsolete in the industrial age. They don’t get removed from the build queues after all, so we might as well extend their useful life.

So what do you think? Is a change necessary? Is the proposed increase in bombard defense too much? All input is welcome!

[Harovan]

Sounds about right. It would make it actually worth to build, well, at least in some cities.

[Fosse]

This sounds good to me. What would sound better would be if the AI built walls more often.

After the AU mod added Walls to the Great Wall, the civ that built it became a much more difficult for me to absorb.

Of course, this is the naval bombard thread, so.... MORE EFFECTIVE COASTAL FORTRESSES!

[Risa]

AI do build walls and coastal fortress, if they have enough time, just like what human do.
I like these changes, including raising bombard strength of battleship to 12, too.

[MrWhereItsAt]

These change sound kinda neat, but I have a thought to voice:

If the AI has a Harbour (allowing vet ships), will they build a Coastal Fortress at all? If not then we need to find another way to get the AI to value Coastal Fortresses.

BTW, I see this change as having effects beyond the mandate for AU (that I think I understand). This is actually attempting a fix to the general problem of the uselessness of Coastal Fortresses rather than just focussing on improving the AI. However, if in fact these changes discourage the AI from mindlessly bombarding cities and actually encourages them to bombard improved tiles or do other useful naval things as you surmise, it will be worth it. If the AI continues to bombard cities uselessly, there is no need for ANY of these changes, as all it will do is improve the usefulness of Coastal Fortresses. If the AI doesn't build these either, it is not an AI weakness to be improved.

[Risa]

There may be a problem: If coastal fortress will drive AI to bombard surrounding tiles, why player would build it?

[MrWhereItsAt]

You have a good point there Risa....

Perhaps if navies had lethal bombard for Battleships etc, but then we are getting perhaps a little too far into changes.

[nbarclay]

With how rarely I bombard cities with ships on any significant scale, encouraging the AI to build coastal fortresses would be far more likely to hurt it than to help it against me. That is doubly true with C3C's changes to bombardment, since it sounds like bombarding rear-area cities in an effort to reduce their population and destroy their improvements is no longer practical.

As far as I'm concerned, the best solution to the coastal fortress "problem" is simply to ignore coastal fortresses. I think I only ever built the things in one game up to now (at least playing under regular rules), and I will be perfectly content to continue to ignore them.

Nathan

[ZargonX]

Risa raises a very good point; while having the AI spend 5 minutes uselessly bombarding my cities until all units are in the red is annoying, I would not willingly create a situation where they tore up my improvements instead This may be one of the tougher problems to iron out, as I can see few solutions that would both benefit the AI and not give the human player more advantages...

[alexman]

Originally posted by Risa
There may be a problem: If coastal fortress will drive AI to bombard surrounding tiles, why player would build it?

Because human players like to leave their cities undefended, or at least much more lightly defended than the AI, so a CF will protect the city improvements and population if there are no more units to damage.

By the way, I was just speculating that the AI might bombard surrounding tiles. I don't know if this will be the case.

[alexman]

Originally posted by nbarclay
With how rarely I bombard cities with ships on any significant scale, encouraging the AI to build coastal fortresses would be far more likely to hurt it than to help it against me.

According to Risa, the AI already builds some CFs, so perhaps we don't need to encourage the AI to build more of them. In this case, strengthening this improvement will no doubt help the AI. At the very least, it will provide more options, which is a major goal of this mod.

By the way, I expect naval bombardment to become more important in C3C than it was in PTW, given the new power of Marines and the realtive vulnerability of defending units.

[alexman]

[Edit: removed the call for a panel vote, as we now have a new proposal on the table for discussion - see my next post]

[Catt]

@alexman - did you do any testing on how the change to coastal fortresses plays out in an engagement? i.e., a scenario with a bunch of AI ships and human cities with CFs just to see what happened and how it came out? I'd be curious if you did.

Catt

[alexman]

I just did some tests.

Unfortunately, the AI doesn't consider the strength (or even the presence) of a Coastal Fortress when it selects its target.

By the way, AI target selection is weird, to say the least: the first targets are cities with ships, then cities or tiles with Workers, then defended cities, and then cities or tiles with bombard units (!). Resources are never targeted unless they are under something else (like a worker or catapult). If you leave your cities undefended, the AI will not bombard them. If you have a unit (even a worker) in your city, the AI will continue to bombard even after the unit has no HP remaining to destroy, so improvements and population will be destroyed.

Going back to the Coastal Fortress, if we increase its bombard defense, the only reason to build it would be when the AI has amphibious capabilities. If the AI doesn't have Marines (or Berzerks) it's best to just leave your cities undefended.

Now if the AI had Amphibious capabilities in the Middle Ages, things would become much more interesting. The human would be forced to defend his cities, and the AI would have a valid reason for targeting units in cities (which it already does).

So what if we give Medieval Infantry Amphibious capabilities? I know this is a big change for the AU mod, but it would make things much more interesting in terms of strategy, and it would help the AI, which defends its coastal cities anyway.

The cost of Medieval Infantry would probably need to be increased (or the cost of Berzerks reduced) so that the Vikings retain their advantage.

[vmxa1]

Originally posted by alexman
I just did some tests.

(!). Resources are never targeted unless they are under something else (like a worker or catapult). If you leave your cities undefended, the AI will not bombard them. If you have a unit (even a worker) in your city, the AI will continue to bombard even after the unit has no HP remaining to destroy, so improvements and population will be destroyed.

This is potential exploit.

[Catt]

Originally posted by alexman
By the way, AI target selection is weird, to say the least: the first targets are cities with ships, then cities or tiles with Workers, then defended cities, and then cities or tiles with bombard units (!). Resources are never targeted unless they are under something else (like a worker or catapult).

Yes, I've seen this in epic games -- it is really frustrating. An AI had marines which meant I was protecting my coastal cities. I left resources totally uncovered -- several sole-source luxuries or strategics were within range, but never targeted until (i) an arty took position in the tile to bombard a naval unit, or (ii) workers entered the tile to clean pollution, and then the tile was bombarded to craters.

I absolutely refuse to place 0 A/D units on resources just to induce an attack by the AI, but watching ships and planes bombard cities defended with infantry or mech infantry (without a follow-up amphib invasion) instead of a nearby single source, unguarded rubber, oil, or luxury is maddening to no end, especially since a barracks in the city means the units are healthy next turn.

Firaxis / Breakaway / Atari - fix bombardment please!

Catt

[lockstep]

Originally posted by alexman
So what if we give Medieval Infantry Amphibious capabilities? ... The cost of Medieval Infantry would probably need to be increased (or the cost of Berzerks reduced) so that the Vikings retain their advantage.

Maybe this deserves a thread of its own ... Anyway, I'd rather make the Longbowman amphibious (and more expensive) because a) an AI without iron still would be able to do amphibious assaults and b) the Berzerk is based on the Longbowman, after all.

[Kuciwalker]

How about Archers too?

[alexman]

Somehow I missed this thread for voting.

AU mod panel, you have 24 hours:

1. Yes/No: Should the bombard defense of Coastal Fortresses be quadrupled?
2. Yes/No: If 1. results in "Yes", should the Coastal Fortress get the ability to build veteran ships?
3. Yes/No: Should battleships have their bombard strength increased to 12?

We will consider the possibility of Medieval amphibious units in another thread.

My vote:
1.Yes
2.No
3.Yes

2 gets a "No", with possible reconsideration if we mess with amphibious units.

[Stuie]

1. Yes
2. No
3. Yes

[Theseus]

1.Yes
2.No
3.Yes

[Catt]

What does increasing the defense of CF's do?

Catt

[alexman]

It makes them harder to get destroyed by naval bombardment. You need to kill a CF before being able to damage anything else in that city (units, population, or improvements) with a ship.

[Catt]

Originally posted by alexman
It makes them harder to get destroyed by naval bombardment. You need to kill a CF before being able to damage anything else in that city (units, population, or improvements) with a ship.

Sorry for my brevity with the question

What does it do (or is it expected to do) with respect to gameplay? I thought that, absent changes by Firaxis to naval bombardment targeting, it will only ever make sense for a human to build one if (i) the AI has amphib abilities and the fear of those amphib abilities induces the human to put defenders in a coastal city; and (ii) the fear induces a human to put a only one (maybe two) defenders in place, meaning a concerted AI bombardment attack against a city might eventually get to the underlying city improvements. WRT the AI, it either will induce the AI to build them more often (is this good?) or it will have no effect on the AI's decision to build them.

IOW, absent a Firaxis tweak to the bombardment targeting algorithms, does making a change to the CF have any expected gameplay changes, and are the expected gameplay changes positive? Based on the panel votes, I assume the answer is "yes" to both questions, but I'm just not divining the specifics from the thread.

Catt

[alexman]

Catt, you are correct in what you say above: if the human leaves his coastal cities empty, the AI won't bombard his cities, so there is no reason to build a CF.

There is now a reason, however, to build a CF, if the city is not empty. For example, if the AI is the Vikings, or if he has Marines, or if you need to garrison your city for military police, or if the coastal city is close to the border with the AI so you fear a ground sneak attack...

Previously, there was no reason to build a CF because it would get destroyed so easily when bombarded.

Edit: with respect to the AI, it's not clear whether the change will induce it to build CFs more often. I doubt it, but if it does, I think the AI will benefit. AI city improvements will be better protected from bombardment (especially from AI bombardment, since AI cities are defended, so they are targets of other AI bombardment).

[Catt]

Originally posted by alexman
Catt, you are correct in what you say above: if the human leaves his coastal cities empty, the AI won't bombard his cities, so there is no reason to build a CF.

There is now a reason, however, to build a CF, if the city is not empty. For example, if the AI is the Vikings, or if he has Marines, or if you need to garrison your city for MP reasons, or if the coastal city is close to the border with the AI so you fear a ground sneak attack...

Previously, there was no reason to build a CF because it would get destroyed so easily when bombarded.

Thanks!

Catt

[lockstep]

1: YES
2: NO
3: YES

Better a city improvement that may be useful on special occasions than a city improvement that is utterly useless.

[alexman]

geniemalin had a brilliant idea to strengthen coastal fortresses and weaken harbors, IMO.

If we add naval defensive strength to harbors, they will be destroyed before units in naval bombardment. Provided the defensive strength is low (like 1), this would make harbors weaker and coastal fortresses stronger at the same time!

By the way, this works even for Wonders. If we add a defensive strength to the Great Lighthouse, for example, the Wonder can be destroyed by naval bombardment. I'm not saying we should do that, but it's kinda cool, and adds another reason to have a strong navy.