I have updated the program, it now includes overall and individual batten angle adjustment, a leech angle parameter, individual luff height adjustments, and a center of area calculation. Selecting a panel now shows the lengths of all panel edges and the angles of the corners. I also fixed some issues with the main sliders for overall sail dimensions that were causing a reset to changes made to individual panel adjustments, but some resets still occur, for instance if an individual batten angle is changed, adjusting the overall batten angle will override the individual change. Because of that I added an undo button, as well as a save/load function. Undo stores up to 20 changes and saving a sail will download a .json file that can be uploaded. There is also a whole sail output in the panel patterns tab, which will download a schematic style .jpg.

Max, here is the github page.

https://github.com/claytonindustry/junkrigsaildesigner.git

David, hopefully the center of area calculations are correct, I do not have much experience with that.

Arnie, well said, whatever gets the job done indeed, that's my kind of thinking!

-Colin Clayton

Arne wrote:

Graeme, you wrote:

“What is it about CAD which makes a sail plan any better than one generated by manual drafting?"

To me, the QCAD program is dead stupid, but also very quick and accurate  -  exactly what I need. I regard it just as a digital drawing board. The only thing it can calculate, apart from distances and angles, is the area of any shape. Very useful when drawing sails. My CAD program simply speeds up the drawing process so that I can finish a drawing, and even a few extra versions of it before losing steam and giving up.

Arne

Yes, when I changed from pencil and paper to CAD in my professional work as a designer, in about 1988 I think it was, it was a change from "that'll have to be good enough, I can't rub out and redraw any more, or I'll end up with a hole in the paper" to "OK, now I can make half a dozen design variations, choose the best ones to take further, cut and paste bits from one design to another...". CAD is the drawing equivalent of word processing tools for a writer. It's not magic, you still have to know how to design, and what to design; it just makes the process easier and quicker.

Arne, to be clear, AI is not creating the sail, it only wrote the code that the program operates on. The default sail that the program loads with is my design and although it will auto calculate when some parameters are changed, they are all calculations that I outlined for AI to include, so I would consider whatever the program outputs as natural intelligence. I included that for users who are not as experienced in sail making and would find some aids helpful. If one wanted to create a sail and needed the boom to be 10 feet for a particular boat, or the mast a certain height, I wanted a tool to help them with the sail making process.

There is a free program called Sailcut CAD, and I thought it would be neat to have something like it but specific to Junk sails. The main reason I found my program interesting was its ability to output G-code files that could be given to a laser cutter, or a pen plotter. Admittedly, it may be hard to find a machine large enough to be useful, but the venture remains possible. Of course there is more to making an effective Junk sail plan, as you know, and you have much more experience in those fields. Center of effort and mast placement calculations are not something I have worked with. Nonetheless, for sailors out there with boats capable of being readily converted without much modification, I think this program could be helpful, I hope! If there's something you think could be added that might help your workflow, or another program entirely, I would be happy to build it for you. I pay for a subscription and whatever isn't used is wasted, so please let me know!

Graeme, I am glad you had fun! The batten angle is a good addition, I will work on that for the next version. I think the text may be a little small, and perhaps the color scheme could change as well. The sky is the limit, it was all made from scratch so any ideas are very welcome. I am certainly not a huge proponent of AI, or of  how many people use it as a knowledge base, but for coding in particular, I would have no idea where to start coding a program like this and AI literally speaks computer.

-Colin Clayton

I had a little play with this, thought it was rather fun, and was impressed with what it was able to do, despite its limitations. I must say, I have a soft spot for this kind of project. Like any design tool it does have its natural limitations, and perhaps Arne is being a little harsh in requiring “what you think made the sailplans better than sail plans generated by natural intelligence". One might just as well ask “What is it about CAD which makes a sail plan any better than one generated by manual drafting?" The answer, of course, in both cases, is: “Nothing”. These things are calculation tools in the hands of a designer, not claiming to replace the actual designer. This is not AI designing a sail, nor is it claimed to be.

What do these tools do? They automate some parts of the design process by taking over the drudgery of calculations and drafting, and also eliminate arithmetic errors (which is not a trivial thing). Some people, who are quite capable of sewing a sail, are not necessarily as confident at maths (or drafting). I quite like this sort of thing.

This particular tool shows what could be done. In this case, useful, if one has decided on a rectangular planform, or, if the intended design is a simple HM type with two (only) triangular upper panels and identical rectangular lower panels. Which reveals the one severe limitation - it does not appear possible to provide for batten rise, which, in most cases will be necessary, for practical reasons. If this extra dimension were provided, it would be very easy for anyone, without ability at drafting or maths, to very quickly produce a sail plan based on either of these two simple planforms.

Personally, I would be reluctant to innovate in the design of a sail, and my own preference of planform is outside the range of these two simple types. I would prefer to make a scaled down (or up) version of one of the popular and proven planforms (Arne’s Johanna, or Slieve’s Amiina, for example, both of which I have made, in scale versions). In both cases – especially in the case of the Amiina – a certain amount of mathematical calculation is required and I would gladly have used such a tool had it been available. The fanned “Reddish” type of sail, which is still seen from time to time, and the "Fantail" and “Weaverbird” types also are outside the scope of what this tool can provide. So, it has its limitations. Still, it is a clever device and provides all that is necessary for someone who just wants a very simple planform, of a type which has proved to be suitable enough for a simple, home-made dinghy sail – examples of which can be found in JRA Magazine #98 (A laser named Thetis) and the upcoming magazine #102 (Cruising the Gulf Coast of Florida).

The great thing about this forum is that one never knows what to expect next, a real melting pot for original ideas. Thanks, Colin.

Wow, Colin, sounds fantastic.  I’ve never designed a sail or built one so will leave it to others to respond on the technicalities but this kind of innovative thinking offered to the broader community is exactly why I am proud to be a part of it.  It’s all of those who not only share their own work but actively respond to the needs of their fellow sailors that make this Association.

As ignorant as I am, I’m going to have a little play with this and see where I get to

thanks indeed