I would say more, it's close to impossible to get the desirable result and that's why I glue instead of sewing.
If I get it right.. Well, it's worth it

Good luck with machining parachute silk. It is an absolute b----r !😉

Thank you so much everyone for the suggestions.
Funny how I used to shop at nylet but completely forgot, I guess the ageing process is in progress😉

Since we are on the subject i must add I never liked thick-ish fabric for a scale model. It simply doesn't act as it should. What it does however is a parachute silk. The movement is just so convincing. This is the kind of fabric I'm going to use for Bluenose.
For now Valdivia will receive (hopefully) similar to original kind of sails.

I did order ripstop nylon but then realized it has that silly square grid pattern. Won't do unfortunately.

Could be worth giving Martin a ring, he makes excellent sails and could probably point you in the right direction..

https://www.housemartinsails.co.uk/

Hi Andy, The company you need if you hvnt already tried is a company Called NYLET. I have been dealing with them for years, a mine of info, they supply fabric for all types of yachts from vintage to racing yachts. Just tell them what boat it is, they will probably know the vessel, they may have tempates even for the sails. Or can make the sails from your measurements. They have a very informative website for yachts persons.
I am or was, just into model rc flying seaplanes until introduced into 1 mtre yacht racing by a friend, sadly rip. But into rc yachts now. Cracking sport when winds too strong to fly planes. Hope this helps. Mike,flyer.🤞

Hello Andy
your description of the material you are seeking could be ripstop nylon. I have used this for many years both in kite making and also for sails on my boats. The lightest weight generally available is 2 oz / 60 gsm which I have found just fine for my boats. It is available on-line (ebay) and is only around £4 a metre. The next weight up (heavier) is 3.8 oz, ie nearly twice as heavy. I have also used this for boat sails but it is stiffer. Sometimes this is preferable.
With ripstop nylon the cut edges do not tend to fray, so I have turned the material just once for the hems. This makes for a flatter edge than turning it twice which is necessary with other types of material. Yes, I make all my own sails and machine sew hems. On some sails I have used bias binding along the edges rather than hem the material. It makes for a firmer edge when using the lightest sail material, which helps when it comes to sewing cringles.
Chugalone has given some excellent information for sail making which is appropriate to cotton sails that replicate the originals as close as possible. However, should you be wanting to create good looking working sails without needing to replicate the look of the originals then perhaps ripstop nylon is the stuff for you.
Happy sewing ! 😉

I made a sail out of real sail material that I got from a marine supplier. I ordered the lightest they had. So far it has lasted more than 40 years. Hope this helps

To stiffen the sail so it will keep the shape I wanted it, I made a 70/30 white glue solution and brushed into the cloth.

let it out in the Florida sun and it was dried in a few minutes.
After it dried front the first coat of the water/glue solution, I diluted the existing formula once again but this time to be 85% water and 15% glue.
This permitted me to spray it with a bottle in the back and front of the sail without detaching it from the jig.
I kept some paper towel to absorb the excess puddles.
I’m pleased with the final results.

Next step was to tight the ends in a way that will leave the sail in a relax and filled shaped.

I know that this section that I will explain does not apply to r/c models but it does if you build a static model.
There many ways to make the sails look filled, but I did this weird looking contraction to help me achieve that.