Hi everybody !
A few days ago I tested a new sail (origami SJR) for my foldable dinghy.
The wind strength was 5 to 15 knots. By the end of the day the wind had increased to 15 knots and there were small waves on the lake. I prefer not to sail in stronger winds because the structure of my foldable dinghy is still too weak.
The sail worked very nicely. Tacking, gybing, reefing – no problems. The swinging boards also worked very well. Following Graeme's advice - I raised them a bit and as a result the CLR moved a bit towards the stern (thank you Graeme).
I made the sail as simple as possible. I did not sew the panels, I only used 45 mm wide double-sided adhesive tape.
I placed string (or polypropylene tape) inside some of the edges of the panels. I don't expect to use this sail for a long time, I just wanted to see if the SJR sail would work well on my foldable dinghy.
EDIT (at the end of season): After about 15 one-day sails the darts started to come unglued, so I sewed them in with a zigzag stitch. The sail is still in good condition, I will use it next season.
As you can see in the attached photos - all panels are the same, which makes them easier to make and use. To avoid using additional ropes and cutting battens, I used rigid batten parrels but different from d-formers. I called them "pistol parrels". They prevent the batten from moving forward. Each part in contact with the mast (including the relevant part of the batten) has a rolling element (parrel bead), which protects the delicate epoxy mast.
I used a sail catcher similar to what Graeme used (a variant of the Slieve catcher). A simple catcher clasp can be made by cutting the catcher rod near where the mast slot in the catcher is. The two parts are joined by a sleeve glued to one of them, which allows the second catcher rod to slide out of the sleeve. This rod can then be lifted up to open the catcher. Details in the double photo.
I noticed that the maximum camber in an origami sail is not at the point 1/3 of chord, but at 1/2 of chord, in the main part of the panel. I have the impression that this may reduce the sail's efficiency when sailing close to the wind.
However, operating a junk sail is sensationally simple and easy. The only problem is the sheet - as it is long, it gets tangled in the cockpit, which can cause the sheet to jam. It also happens that sheetlets get caught on battens. I will probably have to use a longer boomkin at the stern and make a sheet box.
Thank you to everyone, especially Arne, Slieve, Paul for their amazing ideas, and mainly Graeme for good advice and interesting ideas. I would also like to thank Kris for presenting his boat (Anna Lucia 2) on YouTube, thanks to which I learned about the existence of JRA and can benefit from your discoveries.
(I prepared this text with the little help of our friend – Graeme. Graeme - beer is waiting for you ;) )