Invasion Requirements

[southkraut]

The manual states that invasions require a 4:1 force advantage, but I'm fairly certain that I've seen invasions succeed with less pronounced odds.

What does the 4:1 number actually represent? Is it a strict lower limit and I've misobserved, do you get drastically better invasion odds once you're above 4:1, or do invasion chances grow linearly with force advantage and 4:1 is just a rough recommendation?

Any information appreciated.

[alsadius]

I can't find it offhand, but I recall seeing a dev post a few days ago saying that you could get invasions at worse force ratios than 4:1, but your odds of invading in any given turn were lower if you lacked that kind of advantage.

[southkraut]

Do we know the odds for a 4:1 ratio, for reference?

[bcoopactual]

Know the odds for firing the invasion or winning it?

I don't believe that 4:1 odds provides a 100% chance of firing. My impression reading the manual is that the odds at 4:1 are very good (guessing somewhere around 80-90%) but it's possible that you could get a bad RNG "roll" and so it may take the next turn or the next, etc. to get under the percentage and fire the actual invasion as the game makes a number check every turn.

Once the invasion is started successfully, you don't have to maintain 4:1 odds for every turn that fighting is taking place although the better your ratio the better your odds of the invasion succeeding and not continuing to the next turn or failing. That chance will also be affected by the results of any battle in support of land combat that occured that turn.

As far as where the 4:1 ratio comes from it's the weighted sum of the number of ships in that particular ocean area.  Each ship of a class is worth a certain amount of points.  In a 1900 test game the B were worth 9, CA worth 6, CL worth 4 and DD worth 1.  BB and BC will be worth more than B.  No idea about strength numbers for CV and CVL yet.  So 4 B (36 pts) plus 2 CA (12 pts) plus 12 DD (12 pts) would be a fleet strength of 60 for example.  As far as I know, the individual tonnage of the ships doesn't matter just the number in each class so a small CL gives the same points as a large CL.  I haven't tested that through to the late game with much larger ships in each class yet though. 

It's similar to how the blockade mechanic is calculated except there is a national modifier for some nations to account for geographic advantage/disadvantage when it comes to blockade.   

[dorn]

I think there could be minimal amount of points needed.

I have target if invasion Philippines and invasion does not start even if I have force advantage over 4:1 and more than 50 points.

[admkotyatkin]

Wanted to invade Sicily when playing as A-H. The Italian fleet was destroyed completely so much that all i was fighting for 5 months was italian KEs, but the invasion didn't fire and i had to sit and continue sinking the damn fishing boats with 3 inch guns strapped on them with a string.

[Blothorn]

Yeah. I have never had an invasion fire in 70 years of game time (roughly half at war), including years with 4+X force advantages.

[tortugapower]

I believe that everyone is just experiencing RNG at work.

It would be really nice to know the underlying mechanics so that there was only frustration at the RNG (which is all part of the show), and not also frustration at not knowing what to do.

[Blothorn]

Yeah. If I got a "%X chance to fire per month (reduced by inadequate total forces in the area)" or the like I would be a lot more ready to accept it was just terrible luck than obscure requirements.

[euchrejack]

May 29, 2019 9:01:36 GMT -6 bcoopactual said:

Know the odds for firing the invasion or winning it?

I don't believe that 4:1 odds provides a 100% chance of firing. My impression reading the manual is that the odds at 4:1 are very good (guessing somewhere around 80-90%) but it's possible that you could get a bad RNG "roll" and so it may take the next turn or the next, etc. to get under the percentage and fire the actual invasion as the game makes a number check every turn.

Once the invasion is started successfully, you don't have to maintain 4:1 odds for every turn that fighting is taking place although the better your ratio the better your odds of the invasion succeeding and not continuing to the next turn or failing. That chance will also be affected by the results of any battle in support of land combat that occured that turn.

As far as where the 4:1 ratio comes from it's the weighted sum of the number of ships in that particular ocean area.  Each ship of a class is worth a certain amount of points.  In a 1900 test game the B were worth 9, CA worth 6, CL worth 4 and DD worth 1.  BB and BC will be worth more than B.  No idea about strength numbers for CV and CVL yet.  So 4 B (36 pts) plus 2 CA (12 pts) plus 12 DD (12 pts) would be a fleet strength of 60 for example.  As far as I know, the individual tonnage of the ships doesn't matter just the number in each class so a small CL gives the same points as a large CL.  I haven't tested that through to the late game with much larger ships in each class yet though. 

It's similar to how the blockade mechanic is calculated except there is a national modifier for some nations to account for geographic advantage/disadvantage when it comes to blockade.   

I think there might be something more than a set point per ship type for blockades and invasions.  My 5000 ton pre-dreadnought battleships weren't giving me the same ompf as the 10000 ton versions.  Dunno if it has anything to do with what is on the ship, my suspicion is that its a factor of tonnage modified by ship type.  It would make sense for the calculations to take into consideration gun size for invasion, as its essentially the weapon range element for ships, although I have no idea if that is even a thing.

[bcoopactual]

What do you mean by the same "oof"?

It's certainly possible that size and gun caliber are taken into account by the program. I just don't see any objective evidence of it. In a 1920 test game my legacy fleet had BB and BC that were 10,000 tons different in displacement within the same class. The smaller BB with 12 inch main guns was worth the same number of points as the larger BB with 14 inch main guns (14 points). Same with the two BC, 11 inch guns on the smaller and 12 inch on the larger (12).

Interestingly in the 1920 start CA were only worth 5 points each and B worth only 4. Might be due to age, they (CA and B) were all over 10 years old. Speed might be used as a factor as well for the B to have dropped below the CA.

[rodentnavy]

May 30, 2019 2:33:14 GMT -6 bcoopactual said:

What do you mean by the same "oof"?

It's certainly possible that size and gun caliber are taken into account by the program. I just don't see any objective evidence of it. In a 1920 test game my legacy fleet had BB and BC that were 10,000 tons different in displacement within the same class. The smaller BB with 12 inch main guns was worth the same number of points as the larger BB with 14 inch main guns (14 points). Same with the two BC, 11 inch guns on the smaller and 12 inch on the larger (12).

Interestingly in the 1920 start CA were only worth 5 points each and B worth only 4. Might be due to age, they (CA and B) were all over 10 years old. Speed might be used as a factor as well for the B to have dropped below the CA.

Bs did indeed start to suffer a downgrade in their blockade value in RTW1 once Dreadnoughts and Battlecruisers matured. Same seems to happen in RTW2. So you start with 8 and end with 4, now admittedly in that game flooding the colonies with your pre-dreadnoughts stored in mothballs for just such a moment could and did eat the French and/or German empires alive but still. 

I do like the new invasion mechanic when it works and the invasion pop up is awesome but like others it would be nice to have some understanding of the underlying mechanics.