This drawing should be all that is needed to get a lug sail made for the scow - in 1999 a local UK sailmaker charged 175 GBP (say, 275 USD) to make a really good quality example in a standard cruising fabric.

The dimensions shown in the drawing were taken from the actual sail made so, for example, leech and foot curvature are as recommended by the sailmaker.

If you are familiar with the bermudan sail, the names of some of the parts of a gaff or lug sail may be unfamiliar, so they are shown on the drawing.