Adventures in Lofting

It starts here - basic "lines drawing" of a hull is arranged in such a way as to represent the shape of the hull in all three axis - X, Y, and Z.  These are quite different from what is normally called a "line drawing"! The lines drawing depict what you would find if you were to slice the hull up on a particular axis. The "profile" is the side view, the "plan view" is the boat as seen from above, and the "body plan" or "sections" show what the boat would look like from the ends In each view there are two sets of straight lines, and one set of curves.		The Lines At the top of this drawing is the profile view. The curved lines are called "buttlines" which are shown as straight lines on the other two views. Next down is the planform. The curved lines here are called "waterlines". By referencing these curves to the lateral lines on the profile view, we can determine where each of the waterlines is located. Similarly, the curved buttlines in the top profile can be located as horizontal lines on the plan view. Lastly are the sections, shown to the right side. These curves represent the cross section shape. The horizontal straight lines represent the waterlines. The vertical straight lines represent the buttlines. The intersection of all these lines (plus a   few diagonals to smooth the bottom) makes a "fair" curve. A fair line is free of extraneous bumps or hollows. An unfair line needs to be faired, or smoothed out.
		It looks something like this when projected in 3D. Notice how a line is represented in each of the three views. Two views show a straight line while the third shows the curvature.
		Here our hull has been rendered as a wire frame - with hidden lines removed to reduce the confusion.
		Smooth rendered.   The fin keel will be added afterward.   Starting to look like a Catalina 27 yet?
		This one (Triton 29) is a bit tougher due to the deep keel, which must be faired into the hull. But it came out pretty nice in the end. Before computers came into use, this kind of drafting was done full sized on the lofting room floor. Drive nails in to locate the points and bend flexible strips of wood (battens) around the nails to make the curves. Then examine for fairness and adjust as necessary. Doing it on the computer is the same, but harder - or easier - depending on how well you enjoy computer work. But that's the way it's done these days.   On these drawings I've tried to hold tolerance to 1/100 of an inch.

Some others I've done while "learning the ropes"...