it is determined by the length of the shackle passed into
water,in addition to the length from the for'd perpendicular to the
bridge.sum of these two are known as the swinging circle of the
ship.it is radius at which the ship rotates with anchor as the
centre.the radius will not exceed the sum of the lengths.it is
important to check time to time whether the anchor is dragging or
not.swinging circle should be closely watched when the ship's are
nearby.swinging circle can be reduced by standing moor.