Whewther or not you need STCW depends on whether you have designated duties for safety and emergencies, and the main test of that is if your position is on the station bill. nGenerally, if you are on it, even with duties “as directed” you probably need BST.
If all you have is BST, you can’t get an STCW certificate and need to carry proof of the BST cfourses. You can qualify for RFPNW as an OS. In the pre-STCVW past, some ships could carry “Specially Trained Ordinary Seamen” in place of some ABs. What that was vague, but now it’s more apparent, it’s an OS who holds RFPNW. Getting lifeboatman or Proficiency in Survival Craft as an OS will also get you an STCW certificate.
James D. Cavo
Chief, Mariner Training & Assessment Division
USCG National Maritime Center