Do someone know, how I can find Dirty Matty in the Galley on Freyalise Trading Co ship? I was at the Omen Island and drunk against that rat and won but I didn´t get that achievement. Must I make something else?

You need to go look for rats in the Galley. Most times you will find food. From time to time you will find a rat minion. Then on very rare occasions you can find dirty matty drunk and passed out - that's when you get the achievement.

You can play a few times a day, I can't remember how often you can try, but its every few hours.