"That's it; now I gotta cut ya..."

I turned our family room into a sail loft for two days and cut the six panels of the sail.  A real lofting job involves nailing the rough dimensions into the wood floor, marking lines on the same, laying the fabric out all at once and tacking them to the floor here and there.  None of that can take place in my basement.  The next best thing for me was to work on one panel at a time, using some heavy plywood sheets to play the role of loft floor.  I can honestly say that if I didn't have the computer prinouts of each panel's dimensions, I could never have done this (in my basement, which means not at all).

So this is my psuedo-loft.  I aligned the edge of the cloth to the straigth edge of the plywood.  Not shown in this picture is the metric tape measure used to determine the X-axis coordinates, left to right from this view.  The t-square with metric ruler alongside was used to determine the Y-axis coordinates.  The hammer is for tapping a small nail into place.  I thought I was going to use the nails as flex points for a batten.  That didn't happen because the wood moulding I bought far the purpose was not stiff enoughpast a half meter or so.  Plus, the curves involved were so slight, a straight line between points was virually the same as a faired curve.

The string in this picture also didn't last long.  I quickly moved to using the ruler when possible, or other methods to be shown shortly.  Notice the dimensions on the plan?  That's in millimeters--to one decimal place!  Yeah... I SO was able to place my 1.5mm nail at precisely Y=875.3mm.

This is the second panel from the peak and the two nails describe a portion of the head round along the yard.  The next panel contains the point where head and luff meet (the throat).  Honestly, this did not feel like the 50mm of round I plugged into SailcutCAD.  I'll have to check that out once the panels are stiched together.

The shape of the draft starts here.  I didn't capture how far along the chord length this is (or even which panel this is) but this is the point where shaping of the seam begins to depart from a straight line.  In traditional lofting this would have been marked by hand after all the panels were laid out and would have been placed by traditional formulae or by a well seasoned eye.  I have none of that. Thank you Mr. SailcutCAD Computer Dude.

From there, the shape Gradually makes its way inward (upward?).  The ruler is placed up to the leading edge in this pic, so that the seam's end is 590mm away.

...which is here.  So this panel's curve goes from 14.5mm to about 1.5mm over the span of 590mm, and then to zero over another meter or so.  Since the ruler happens to show the imperial measure in this pic, it's clear that I have achieved a 1/2" broadseam whose maximum draft is way past the 590mm mark.  I suppose the gradual slope of this line defines the entry angle of the luff (if indeed this seam is endin at the luff, it could be hitting the head--I forget which panel this is).

We don't need no steenking plotter!  This is the bottom panel and the curve being drawn will define the shape of the foot.  I suspect there will be too much round to lash this foot to the boom; I think SailcutCAD assumes a loose-footed boom.  Anyway, the wood shown here is two strips of scrap luan ply I had on hand, clamped together so I could have a straight edge long enough to reach from tack to clew.  It worked.  SailcutCAD describes all intermediate coordinates in terms of their deviation from the straight line between the endpoints.  For all other panels, that straight line was parallel with the edge of the plywood.  In this case, the line cuts diagonally across the cloth.  Here, the wood is the tack-clew line and the pencil is pointing to the "deviation" point.  Who'da knew sailmaking could be so geeky?

I didn't photograph the panels themselves because I quickly rolled and stored them as the came off the "loft."  Shown here is all the excess material, which will go toward the corner and reef reinforcements.

Next time: panel assembly.