Working as a team, the Six has to get everyone across a swamp before the other Six manages it
masking tape or chalk, copies of a pre printed grid for leaders
tape or chalk a grid on the floor - 5 x 5 squares.
Leader has a printed grid with a clear route on it, and squares with quicksand marked. Cubs can only move forwards, backwards or sideways (not diagonally). If they step on a square with quicksand in it, the leader shouts 'you're sinking', they have to go back to the start and another Cub starts.
To make it more relevant to navigation - label each axis and require the Sixer to tell the Cub on the swamp which way to go by using the co-ordinates of each square. You could also make it a race - Cubs from alternate Sixes go in turn and the winning Six has all their Cubs to safety first (don't forget to make sure equal numbers in the competing Sixes)