ORP Czapla participated in the September campaign of 1939 while still incomplete.
Notes on verification
Confirmed by multiple independent sources (Polish and German Wikipedia, dobroni.pl, TheSecondWorldWar.org) detailing the ship's incomplete state, technical deficiencies, and its sinking during the September 1939 campaign.
Sources
- ORP Czapla (en.wikipedia.org)
- https://dobroni.pl/n/orp-czapla-ii/13251 (dobroni.pl)
- https://www.thesecondworldwar.org/invasion-of-poland/baltic-coast/hel-peninsula (thesecondworldwar.org)