This is the 13207th most frequent Polish word.
okrętu
The Polish word "okrętu" means "of the ship" or "of the vessel" (genitive singular form of "okręt").
In this sentence, 'okrętu' is the genitive singular form of 'okręt' (ship), showing possession or relation.
Captain zarządził dryfowanie okrętu.
The captain ordered the ship to drift.
Here, 'okrętu' is the genitive singular form of 'okręt', used because the negation of a direct object requires the genitive case.
Nie dostrzegłem okrętu na horyzoncie.
I did not spot the ship on the horizon.
In this instance, 'okrętu' is again in the genitive singular form, used to denote possession by the 'engine'.