AI Naval Invasion Logic?

[hkrommel]

Can someone explain what exactly factors into the AI deciding to do a naval invasion?

In my last two playthroughs as Germany the British/French continuously land small amounts of troops on provinces without ports. Naturally, these invasions are doomed from the start as I have all ports garrisoned, but the AI should know that, so why do they insist on throwing away tens of thousands of men in pointless excursions? It's incredibly annoying for me as well as I have to wait for my reserves to arrive while these out of supply divisions are somehow able to rampage across the countryside.

More importantly, however, short of naval supremacy how do I deter the AI? If it will invade even if it knows it can't take ports, the only thing I can really do is garrison the entire coastline, which given the German manpower situation is less than ideal.

 

[Admiral Piett]

Naval supremacy doesn't work for me actually. The AI somehow naval lands anyway, even across multiple sea zones where I have naval supremacy. I'm not exactly sure what is going on there.

 

[LostAlone]

I have no idea how it works and I too have had equally frustrating problems with the AI launching naval invasions for seemingly no reason and seemingly out of nowhere. It's so irrational and stupid at times that it genuinely beggars belief. There's a bunch of knock on problems with this too that slap the balance of a game around.

The biggest problem is the AI launching stupid and doomed naval invasions against other AI nations that don't defend properly. For example; in my allied games I frequently see AI allies of mine (typically remnants of Belgium, Netherlands or France) launching amphibious invasions of Italy/Sicily in 1940 and being reasonably successful. And from there the problems snowball; as a UK player do I just let them all die (which will keep the game on a historical timeline) or should I play to my best advantage, reinforce them and knock Italy out of the war by 1941? Neither of these are good situations to be in. Equally, there's the situations as Germany with the UK sending seemingly constant invasions attempts across the channel and all of them dying over and over and over again. It's just not a good thing for the game.

And of course, whoever is launching doomed invasions is losing men and material at a time that it doesn't even make sense for them to be fighting. That's just bad for the game all over. The AI just throwing resources away doesn't feel good no matter the outcome.

 

[CharlieFox]

Naval supremacy doesn't work for me actually. The AI somehow naval lands anyway, even across multiple sea zones where I have naval supremacy. I'm not exactly sure what is going on there.

Apparently it is only needed to have naval supremacy once to execute a given plan. After that you can continually invade with that plan without requiring any naval superiority. If you see the AI always landing on the same province they are reusing the same plan.

Edit: here is a link to a thread where this was explained in detail: https://forum.paradoxplaza.com/forum/index.php?threads/countering-invasions-with-fleets.1007782/