Best Defensive Promotion for a Galley

Hey folks - I play BtS 3.19 on Immortal.

Like everyone, I hate Barb Galleys and do my best to spawn bust, but when the AI leads a galley into my territory, I gotta throw down.

I usually take the Drill 1 promotion, but I thought I'd pose that question to the experts. Assuming I only play defense, is this the optimal play? The other option is Combat 1, but I don't think the statistics are favorable. I don't know enough about the AI advantage when they attack to actually do the math.

Thanks-Frisbee

AI's don't get any advantages when attacking the human under any circumstances.
I never promote galleys to drill. Taking the drill -line means you need to get to at least drill 3 to have any signinficant advantages in battle and when taliking galleys, they seldomly live that long
When talking galley vs. galley action, combat is the way to go. Its a sad fact but you really need triremes to defend against barb galleys effectively

Saru said:

AI's don't get any advantages when attacking the human under any circumstances.
I never promote galleys to drill. Taking the drill -line means you need to get to at least drill 3 to have any signinficant advantages in battle and when taliking galleys, they seldomly live that long
When talking galley vs. galley action, combat is the way to go. Its a sad fact but you really need triremes to defend against barb galleys effectively

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Totally not true. Drill one gives 5% better combat-chances. It's the best promotion for close-fights, so in this case, it is optimum play.

Read the War Academy for Combat-Promotions, there's an Article with Math about it.

No, I'm pretty sure that you really do want Combat I. The 10% strength bonus pushes you past one of those stages that the War Academy mentions. That makes it one of the few places where Combat I is better than an extra first strike. Btw, since Drill I is only worth about half of a 1st strike, I'm pretty sure that C1 is strictly better than C1.

Edit: I forgot to mention: don't forget to let them attack you when you can. That gives you an extra 10% bonus, which increases your odds tremendously when your strengths are near equal. Very important for galleys vs. galleys and somewhat important for even trireme vs. galley fights.

No, not true Um, otherwise, link.

Drill is the best promotion for close fights (Galley vs Galley) and hightens the chance by the biggest value.

Source: This Article from the war Academy.

First strikes make the most dramatic difference to pure winning percentage when the two fighting units are very close in strength. Two units with identical strength and equal first strikes each have a 50% chance of winning (YAY! Something that finally makes sense in this mess of math). Give 1 a single first strike, though, and the odds of that unit winning goes up to 56.8%.

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Seraiel said:

No, not true Um, otherwise, link.

Drill is the best promotion for close fights (Galley vs Galley) and hightens the chance by the biggest value.

Source: This Article from the war Academy.

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Drill has the most effect in close fights, but that doesn't mean it's better than combat. Due to breakpoints, combat is usually better (it swings it to like 60+%). However, it's not an even fight because of the coastal defense, though mathematically combat is still probably better than drill 1.

I might go drill for triremes vs a lot of barb galleys, just to try to minimize damage.

A quick-and-dirty script simulating 10 million combats each gives these results...
Galley vs. Galley, no promotions (but coastal defense bonus in all cases): Attacker has 47.6% chance of winning each round and does 19 damage on winning; defender does 20 damage on winning. Defender wins ~68% of the time (the attacker needing to win a whole extra round really hurts his chances).
Galley vs. Galley, defender has Combat I: Defender wins ~73% of the time.
Galley vs. Galley, defender has Drill I: Defender wins ~71% of the time.
Galley vs. Galley, Defender has Flanking I: Still 68% chance of victory, but 71% chance of survival for defender.
Galley vs. Galley, attacker has Combat I: Exactly identical; 50% chance of victory for defender.
Galley vs. Galley, attacker has Drill I: 65% chance of victory for defender.
Galley vs. Galley, both sides have combat I: ~68% for defender.
Galley vs. Galley, both sides have drill I: ~68% for defender.
Galley vs. Galley, Combat I att. vs. Drill 1 def: ~57% in favor of defender.
Galley vs. Galley, Drill I att. vs. Combat I def: ~70% in favor of defender.

Conclusion: Combat I is better in close matches (like Galley vs. Galley). This is especially true near the break-points where your strength matches theirs - a mere +0.0001% strength boost to one side in a mirror match will change it from 50-50 odds to 5-to-3 odds favoring the stronger.

Build a Trireme.

Vicawoo -- Combat 1 makes sense if you don't have a coastal bonus or have 50/50 odds, but as soon at it's 51/49, I maintain that Drill is a better short term option.

Coanda -- Does your script account for the Player bonus against Barbs? (I forget what it is on Immortal). I doubt it makes much difference because it won't take you over the next damage step (25dam for, 16dam against).

And yes, Trireme is the best choice, but sometimes Metal Working isn't available. My original question was simply my attempt to optimize.

frisbee said:

Vicawoo -- Combat 1 makes sense if you don't have a coastal bonus or have 50/50 odds, but as soon at it's 51/49, I maintain that Drill is a better short term option.

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The other way round. With 50/50 Drill is better, when you're weaker, Combat is better.

frisbee said:

Coanda -- Does your script account for the Player bonus against Barbs? (I forget what it is on Immortal). I doubt it makes much difference because it won't take you over the next damage step (25dam for, 16dam against).

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A good question, because I hadn't even thought about it when setting it up (as I said, it was a quick-and-dirty script). That said, results stand on Monarch+ - barb bonus (iBarbarianBonus) is -40 on Settler, -30 on Chieftain, -20 on Warlord, -10 on Noble, -5 on Prince, and 0 on Monarch+.

Seraiel said:

The other way round. With 50/50 Drill is better, when you're weaker, Combat is better.

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I admit to not reading the War Academy article in the past year, but my understanding is that Combat is the correct promotion if it takes you over the next damage step function.

At even odds, everyone does 20 damage
Give yourself Combat 1, and you do 20dam, the opponent does 19, and your chances of victory climb considerably.

Drill 1 makes sense if you already have a small advantage (like the coastal bonus or bonus vs Barbs), and Combat won't take you up to the next damage step (24/16?).

Just trying to understand.
--Frisbee

Combat I is better at 50-50. Specifically, check if taking a promotion can push you to the other side of one of these ratios: 72% of other unit's strength, 100% of other unit's strength, 139% of other unit's strength. Going from 72% to 73% of their strength functions much like a guaranteed-successful first strike (you don't need to roll to hit) that cannot be ignored, as well as slightly improving your combat odds on every other round. This is because instead of needing 7 hits to win the combat, you only need 6. Going from 99% to 101% is twice as good - you need only 5 instead of 6, and they need 6 instead of 5 - demonstrably better than simultaneously giving you a first strike and taking a first strike away from them. Going from 139% to 140% means they'll need 7 hits instead of 6.

There are obviously other transition points beyond those three if you want to go digging for the numbers, but those three are the ones that are fairly trivial to check yourself in your head during a game.

So we are agreed (not really a matter of opinion if you crank the numbers) - On Immortal, Drill 1 is marginally better than Combat 1 for Galleys.

frisbee said:

So we are agreed (not really a matter of opinion if you crank the numbers) - On Immortal, Drill 1 is marginally better than Combat 1 for Galleys.

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The numbers that the game displays do not agree with this

This is defending on coast.

nothing 67.8

d I 70.7
d II 76.3
d III 81.1
d iv 89.1

c 1 72.8
c 2 76.9
c 3 87.8
c 4 90.1

so combat is always better than drill

I'm not convinced. I looked at that War Academy article, and it was as I remembered it. The defender goes from an R value of 1.1 to 1.21, which is good enough to pass a "jump point" as the author puts it:

21/17 (1.24)
41/37 (1.11)

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And, as Coanda explains, a promo that pushes you past one of these points is quite a bit better than a first strike (which is quite a bit better than D1). Btw, the attacker would also go up a jump point. In fact, the even odds jump point is the most important one, as Coanda explained (well, he explains going from 50/50 to something else, but it works in reverse, too).

Btw, Coanda, flanking does nothing for the defender .

Um the Muse said:

I'm not convinced. I looked at that War Academy article, and it was as I remembered it. The defender goes from an R value of 1.1 to 1.21, which is good enough to pass a "jump point" as the author puts it:



And, as Coanda explains, a promo that pushes you past one of these points is quite a bit better than a first strike (which is quite a bit better than D1). Btw, the attacker would also go up a jump point. In fact, the even odds jump point is the most important one, as Coanda explained (well, he explains going from 50/50 to something else, but it works in reverse, too).

Btw, Coanda, flanking does nothing for the defender .

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It might be that you and I are right Um. The thing in this example is: The Galley has already 10% Bonus from being near the coast. Therefor, it already has passed the Jumppoint of which you talk. That's why Drill Promotion is better.

Drill is better in any example where no Jumppoint is passed, and it's better at 50/50.

Here is an explanation that Arathorn (the author, apparently) provided in a later post in the same article:

Arathorn said:

Also, first strike is quite compelling. It's better than +10% strength in these cases. Of course, if the +10% strength can put you over a "jump point", it's going to clearly be better. If not, though, first strike is pretty strong. It just makes more difference in the "close" case than the blowout case.

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coanda said:

A quick-and-dirty script simulating 10 million combats each gives these results...
Galley vs. Galley, Defender has Flanking I: Still 68% chance of victory, but 71% chance of survival for defender.

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Doesn't Flanking work only on the attack?

Um the Muse said:

Here is an explanation that Arathorn (the author, apparently) provided in a later post in the same article:

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Note however, that drill I is only 50% chance of a first strike. I believe both Seraiel and coanda have this wrong. This devalues the whole drill promotions line, and keeps it below combat at all times, altough the difference between D2 and C2 and D4 and C4 is small.

win% when defending on coast with no promotions:

67.8 %

now D1 only adds 2.9% to this and C1 5%.

D1 70.7%, C1 72.8%

the situation becomes more favorable with D3, because you get a full 1st strike.

D2 76.3% C2 76.9%

You would think D3 would now outscore C3, but there's a jump point at 39% stronger,
so combat jumps far ahead here.

D3 81.1% C3 87.8%

Drill4 is about twice as good as D3 and D2, but it can't quite close the gap.

D4 89.1% C4 90.1%

I worldbuildered a lot of different galley's on coast tiles. The were actually the attack odds, displayed with alt+mouse over, and then subtracted from 100%.

So either drill is worse in all cases or the in-game odds display is broken.