How to add patches, reef points and battens. Sailmaking isn't just sewing seams, it also includes several complex parts. Boat builder Bob Emser explains all of these parts and shows some tips on constructing them. It this part 2 of sail making for "Skylark", Bob's Haven 12 1/2, the main gaff is constructed using a precut designed from Sailrite. This sail plan will also work for a Herreshoff 12 1/2 and a Some Sound 12 1/2.