and one thing about Poland and colonization...
it came to my mind that Poland was one of the first countries in europe that started colonization

but as I said before, Poles didn't use ships
in less then a century (between XV-XVI century) Ponad siezed the teritory of additional 500 000 sq km; thats twice as much land as UK has at present. Poland merged with Lithuenia and conquered land of present Ukraine, reaching 1 mln sq km. I know that its not much, comparing to US, but in the European terms its much (3 times bigger than nowadays Germany).
The eastern teritories had low population density but with a veriety of ethnic groups and religions. The "Drang nach Osten" was limited by wars with Russia and Otoman Empire. Many wars were won and lost. For a short period Poles even established a Tzar in Moscow
Why Poland didn't colonised Africa, America and so on, as the West-European countries did? First, Poland have limited access to the open sea. Tte latter, Poland didn't have to go that far to conquer a new land.