The ORCA's are classified as tenders and captained by an OIC.
Since the applicable orders have not changed, a Tender Command Certificate is all that is needed to be OIC.
In view of their greater complexity as compared to YAG's, it is logical to think that a conversion course is required first and that the current tender commad course will be expanded somewhat.
This said, however, the Tender Command Certificate will still only permit the holder to do day sailing in good visibility unless also a holder of a BWK - no night steaming or blind pilotage stuff - unless they change the limitations. With those restrictions, there is little doubt that a QL5 Bosn should be able to handle them, though.