Making the junk sail – part 1

Finally making the sail. The end is in sight!

Fabric

The sail is made from 65gsm polyester ripstop. This is the same fabric as I used in my previous boat. The reasons for choosing it were:

  • It is cheap;
  • Since it is coated it is impermeable to air, plus it doesn’t fray when cut;
  • It doesn’t stretch (much) on the main thread axes – along the fabric and across the fabric;
  • It does stretch on the bias (diagonal). This helps take out creases when using barrel cut camber;
  • Polyester is UV resistent and doesn’t sag when wet;
  • It seems to work ok.

The main downside is that the coating will probably wear off in time which will allow air through.

This fabric is available in a wide range of colours – I chose white for the main panels and yellow (to match the boat hull) for the second panel from the top. It is worth noting that the white is easiest to work as it is translucent, which means pencil lines are visible from both sides of the fabric and even through two thicknesses of fabric. This makes it much easier to line everything up.

As with my previous boat I made the batten pockets from thicker fabric – 280gsm polyester.

The main loads are taken by 20mm polyester tape in the luff and leach. The batten pockets are sewn directly to the tape so the only loads taken by the 65gsm polyester are the wind loads.

Equipment

I have a Singer sewing machine that dates to around 1948 – making it over 70 years old. The build quality is fantastic and it works like it was new. If you are looking for a sewing machine for making junk sails you need:

  • Metal gears to cope with thick tape and multiple layers of cloth;
  • A motor – hand cranked machines are cute (I’ve got another Singer from 1898 that also works like new) but only leave one hand free for controlling the cloth. Treadle machines are fine though.
  • Direction reverse. This makes it easy to lock the thread at the start and end of the seam.

I think the needles I’ve got are for denim but don’t seem to be critical. It is worth spending some time playing with the tension on scrap fabric to get it right.

Ideally I’d like a hot knife for cutting the fabric but these are expensive so I make do with some cheap pinking shears.

Templates

I make full templates out of lining paper (wall paper) for the jiblets.

Top panel pattern

The basic shape of the panel was drawn up, then the camber was added from the spreadsheet. Finally the pattern was cut out and transferred to the fabric by drawing round it with a pencil. I tried to keep the threads aligned across the width of the panel as these will control the camber.

I then added 15mm hem allowance on top and bottom and 30mm on front and back. With experience 30mm wasn’t enough – I added 60mm hem allowance to the front and back of the main panels.

The panels were then cut out with my pinking shears. It is worth being as accurate as possible with the hems as it makes it much easier to line everything up if the hems are consistent.

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