Here's a breakdown.
1. Determine sail dimensions (and gaff angle if making a four sided sail)
2. Enter sizes into Sailcut CAD (free download) and print out development.
3. Use development to make the sail panels by lofting out on the floor. If you have enough room you can just spread out the tarp and start working, or you can pre-cut it into strips if needed.
4. Start with a baseline and an X zero, Y zero position in the bottom left hand corner for each panel. Plot the XY coordinates and draw the lines using straight edges and bending battens with weights.
5. Cut the panels out and join them together (curved edge to flat edge) using 12mm double sided seam tape.
6. Use strong tape to go over the seams (both sides). No stitching is required.
7. Once all joined up, trim around the edges of the sail to get them neatly straight or curved as you need, using a batten.
8. Reinforce the corners of the sail using two or three layers of tarp cut into triangles to suit. Stagger the sizes and glue them on with contact adhesive. (following product's instructions)
9. Attach a 2mm or 3mm nylon cord all the way around the perimeter of the sail. To do this first attach a strip of 12mm seam tape around the edge of the sail.(set in slightly, see video) Stick the cord to the outside edge of the tape then fold the outer edge of the sail over..encasing the cord inside.
10. Reinforce any points where you want to attach eylets or reefing points using tarp with contact adhesive and finish with strong tape.
11. Reinforce the corners (both sides) with a couple of layers of strong tape.
12. Fold a layer of strong tape all the way around the edge of the sail. To do this, attach the tape to the floor (sticky side up) using a small piece of tape at either end to hold it firm. Straighten out the edge of the sail and bring it over to the tape, covering less than half ( *I said half in the video but closer to a third is better to allow the tape to roll over the cord). Press down on the sail then unattach the tape from the floor and fold the remainder over and stick down.
13. Hand sew rings into the corners.(one each side) with strong nylon thread. Stitch all the way around and over the edge. A hole can be cut on the inside of the rings (near the edge) for attaching the sail to the spars. This way you can attach ropes very close to the corners and tension your sail edges and nothing can break or deteriotate. Much better than just eyelets for these high stress points.
All done! These sails are great for any DIY boat project. Have fun and make sure to store your sail out of the sun so that it lasts.
#polytarpsail #dinghycruising #dinghysailing
#sailingdinghy #diysails
Backing music used in this video:
Intro music at 00.05
Acoustic Folk Instrumental by Hyde - Free Instrumentals / davidhydemusic ​
Promoted by MrSnooze • Acoustic Guitar Instru... ​
Creative Commons - CC BY 3.0 goo.gl/A7jRXA​
Music at 00.16
"String Quartet No. 6 in Bb major, Mov. 2, Op. 18", a free-use public domain song by Ludwig van Beethoven, courtesy of Musopen: musopen.org/​