THE HALF HULL STORY
HALF MODELS: Shipbuilders Original Blueprints
Blueprints do not exist for most of the wooden vessels which were built in Nova Scotia. Instead, the lines and measurements required for construction were derived from carved wooden half models, usually on a scale of ¼ or ½ inch to the foot. Experience determined the shape of the hull. The lines were then marked on a drafting board being simply a plank of 1 inch by two to three feet long.
First the outline of the hull was traced on the board. The outline was then divided into vertical and horizontal sections by a grid of rectangular vertical and horizontal lines. To the left of each vertical line, a curved line leads down to the bottom of the profile. The curves are slim at the bow, bellow out to S-curves amidships and narrow again toward the stern. They are sections as if the hull were to be sliced through the various points from stem to stern. These curves could be copied in a number of ways, often by simply bending strips of lead against the hull at each of the numbered verticals:
Next the lines were laid down on the shop floor. The numbered vertical on the drafting board were the location of the key ribs or frames. The drafting board numbers were the measurements from each vertical to its curved line, defining the curve of the frames as it was laid down full size on the floor of the shop. From the full sized section lines thus produced, the shipbuilder could form the molds which would be the pattern for the ribs of the frames to fit at various points on either side of the keel.
COURTESY: L.B.JENSEN, Saga of Shipbuilding.