They were certainly exaggerating, but there is a way to check for plumb without buying a laser level. On my strongback for my stripper I strung a plumb line down the middle to check the trueness of the board. Also I strung a line between two sticks screwed into each end of the board and plumbed with a framing square in order to properly align the forms. You can use the same idea to check the trueness of your boat. Just string a plumb line between two posts or objects, and place the boat to where the line falls down the middle of the boat and running from the tip of the bow to the tip of the stern. You can measure out from the line sideways to determine the symmetry of the boat. Also if the bow and stern are plumb then the line should fall right down the middle of the boat the whole length of the boat. If it is off in either direction at the center of the boat, then you are out of plumb. In that case either start over, or get a good rudder!!!