Each sailboat in this set is smaller by the square root of two -- the ratio between the diagonal and side of a square.
| Sailboat by James M. Clark This sailboat was inspired by the OrigamiUSA logo sailboat. I wanted to achieve more realistic proportions, even though this makes the design more complex. While developing the design, I discovered a way to make a small tab in the back to hold the sailboat upright or leaning as when responding to wind from the side. Later, I developed methods for making the hull and sails three-dimensional. The hull and sails show different sides of the paper. Choose paper colors as you like; for example, a solid color for the hull and white for the sails, or a white hull and striped sails. |
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1. Start with hull color up. Valley-fold corner to corner. |
 2. Pinch a valley-fold through both layers at the corner, keeping both corners aligned and shaping the paper like a cone. |
 3. This fold is tilted – point C is not at the center of the square as expected. (See next view.) |
The distance between points A and B in the next view should be 1/10 of the side of the square. Separating points A and B too much will give you trouble. (The unusual angle of the fold made in step 3 creates the asymmetrical proportions of the sailboat: the foresail is taller and narrower than the aft sail, and the bow and stern of the hull also differ.)
4. Lift point B and squash-fold symmetrically. |
 5. Corner C should be offset but symmetrical like this. Turn over. |
 6. Lift point D and softly begin to squash-fold symmetrically. (See next two views.) |
7. Flatten point P and turn over before finishing the squash fold. |
 8. Align corners C and D on the diagonal before flattening, finishing the squash fold. Rotate to the position shown next. |
 9. Fold front right corner to the left in front, and the back left corner to the right in back. |
(In views 8 and 9, the model is a modified preliminary fold. For a normal preliminary fold, step 9 – sometimes called a 'minor miracle' – would not change the shape of the model. In view 11, we see the initial shape of the two sails.)
10. Valley-fold top layer from corner to corner. Repeat behind. (See 10d and view 11.) |
 10d. (Optional fussy detail, to prevent a color gap from appearing later, as shown in view 34) When doing step 10, pull the paper a little 'too far' so that the corners at either end of the new crease are stretched a tiny bit as detailed here. |
 11. Mountain-fold the top layer of paper against the thicker edge behind it, then fold flat. Repeat behind. |
(At step 12, you can decide which side of the boat will be the front.)
12. Valley-fold (top only). See view 13 for position. |
 13. Make width of 'a' the same as the width of 'b'. Unfold. |
 14. Now fold a rabbit ear, using the crease made in step 12. |
15. Fold in half, creasing both ways, then sink the triangular area. See view 16. |
 16. Fold the raw edge nearly to the central folded edge of the taller sail. Repeat behind. |
 17. Now fold the shorter sail, front and back, but divide the angle 2/5 and 3/5 as shown. |
18. Unfold both sails, front and back. (Undo steps 16 and 17.) |
 19. Fold all at once, like two petal folds, front and back. Points A and B define the new creases. Be sure that A and B match front and back. |
 20. Be sure that edges C - D match front and back, so that the sailboat can stand erect. Turn model over. |
21. Lift top two layers. Don't flatten the edges. |
 22. Valley-fold triangular flap so that it lies between edges C and D. Valley-fold point E to point F, unfold, mountain-fold, and unfold to firmly crease all layers. |
 23. Open the model loosely. Don't flatten. It should be three-dimensional (3D). |
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24. Check that flap F is positioned as shown. Pull edges A and B apart, then pinch a mountain-fold on the existing crease between A and B. Likewise, pull edges C and D apart, then pinch a mountain-fold on the crease between C and D. The model remains 3D. |
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25. Begin folding the six existing creases in the valley direction as shown. This brings the two ends toward you. Then begin mountain-folding the center creases of these two ends as shown. |
26. This is a 3D view. Turn bottom toward you. |
 27. Sink the bottom. This also flattens the model. |
 28. Flattened model (view from the back). Open the edge of the taller sail. |
Up to step 22, the model was inside-out. Steps 23 to 27 have turned the model right-side-out. When I was developing the model, I struggled to get the paper where I wanted it to be, nearly tearing it, until, unfolding a successful result, I discovered that working the model inside-out at first was much easier to do..
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31. Back side of boat shown here. Do these valley folds. Don't go past the outside edge of the short sail. |
 32. Now reverse the folds made in step 31, tucking the flaps inside, out of sight. |
 33. Like this. Turn model over. |
A small white triangle will show at the stern corner of the hull (under the short sail), as shown in view 34, if the variation shown in step 10d is not done.
34. Valley-fold along a shallow curved line. You cannot do this flat -- the model will bend. Then reverse the fold, and unfold. |
 35. Push down to flatten the deck. Inserting a small stick into the hull from the bottom will help. Pinch to sharpen the deck edges. Smooth the 3D shape of the hull with a small stick inside. Accent the crease at the stern to suggest a rudder. |
 36. Try curling the sails. The fold lines shown here are not for creases, but indicate the orientation of cone-like curves. You may need to mountain-fold the base of the sails a little bit to keep the sails erect. Adjust the tab behind to hold the boat at a leaning angle, as when catching a breeze. |
