who is in de facto command of the jeroboam and why

There is a Shaker on the Jeroboam who had been a great prophet before leaving for Nantucket. Upon leaving Nantucket at sea, the Shaker announced himself as the archangel Gabriel and commanded the captain to jump overboard. Gabriel declared himself deliverer of the isles of the sea. The crew of the Jeroboam staged a mutiny to prevent maltreatment of Gabriel and became obedient to him.