Two boats approaching a mark on a beat, the windward boat Boat B is passing Boat A but is not clear ahead. The mark is thirty metres to leeward and at approx 90 Deg to the direction of travel. Boat A continues to a point very close to a moored boat and then bears away towards the mark. Boat B bears away but has to fall in behind Boat A or hit the moored boat.
My thought is that Boat A did not stear a proper course.
But I'd like to know