If anything unusual does occur in the night, the Anchor Watch immediately informs the senior crew (usually Mr. Mangrum, who is typically up and working in the great cabin), who can then react accordingly. At the end of each team's hour-long shift, they must wake their replacements — and ensure that said replacements really are awake and alert — before they are free to return to sleep. Thus, Anchor Watch both safeguards the Half Moon and ingrains its crew with a standard of discipline and responsibility.