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Step 2Make a Plan
The first thing to do is to figure out exactly what you want to make.
There's a lot of mathematics and physics involved in designing a sailing rig properly, so I'm just going to present what I've made and leave you to decide what's right for you. For my boat I designed a low-aspect, boomless, Spritsail. The dimensions-ratio formula is only for a low-aspect spritsail, other sail types will be different.
It's ok to make several drawings with each only presenting certain information, or just noting things without drawing them. Do whatever works for you, or get someone that enjoys drafting to help you make your plan.
To sketch out your sail you need to know some basic measurements. For example I knew I wanted the luff, the side next to the mast, to be 6 feet tall. So, based on a formula in my book, I can figure out the other measurements.
the formula, followed by my measurements.
luff - 1.0
leech - 1.365
foot - .944
head - .666
diagonal peak to tack - 1.555
diagonal throat to clew - 1.222
luff - 72 inches
leech - 98 1/8 inches
foot - 68 inches
head - 48 inches
diagonal peak to tack - 112 inches
diagonal throat to clew - 89 inches
knowing all these I used the 3/32 scale on my ruler and sketched my outline.
Start with the luff. then set the compass for the throat/clew diagonal and mark the arc. measure the distance from the tack to the clew and mark where it meets the arc. Set the compass for the head measurement and mark down that arc. Then measure from the clew to the head and mark where it meets the arc, then connect that point to the throat.
Next mark your foot curve. Again consulting my book I made a foot curve 2 inches, the deepest part of the curve being directly in the middle of the foot.
The next thing to decide is how you're actually going to sew it together.
For the edges I went with cut tablings(I'll explain it later), 1 1/2 inches on the foot, luff, and head and 5/8 of an inch on the leech. To draw these on measure in from the edges.
How wide will the cloth between seams be? Usually this is dictated by the width of your material, but on such a small sail there's room to tinker. Most commonly cotton cloth is 36 inches wide, mine however was 44. I decided to make seams every 12 inches, I had to sew some false seams which complicated things a bit. The seams were 1/2 an inch wide. Draw these on your plan.
Will you be adding reefing points? I know it's pretty excessive and unnecessairy for a sail this small. But if you do, generally you'll want these to reduce the sail about 30%. For mine they would start 21 1/2 inches up from the tack and follow the curve of the foot.
Next thing to do is to design your patches. After looking at some different types I decided on traditional looking curved patches. A basic guideline is that patches should be 1 inch long for every foot of sail edge it is applied to.
Then mark where any metal or other hardware will go. Along the luff I've got eyelets every foot. There would be eyelets in each reef point. There is a brail eyelet, 50 inches down from the peak in the leech.
There's a lot of mathematics and physics involved in designing a sailing rig properly, so I'm just going to present what I've made and leave you to decide what's right for you. For my boat I designed a low-aspect, boomless, Spritsail. The dimensions-ratio formula is only for a low-aspect spritsail, other sail types will be different.
It's ok to make several drawings with each only presenting certain information, or just noting things without drawing them. Do whatever works for you, or get someone that enjoys drafting to help you make your plan.
To sketch out your sail you need to know some basic measurements. For example I knew I wanted the luff, the side next to the mast, to be 6 feet tall. So, based on a formula in my book, I can figure out the other measurements.
the formula, followed by my measurements.
luff - 1.0
leech - 1.365
foot - .944
head - .666
diagonal peak to tack - 1.555
diagonal throat to clew - 1.222
luff - 72 inches
leech - 98 1/8 inches
foot - 68 inches
head - 48 inches
diagonal peak to tack - 112 inches
diagonal throat to clew - 89 inches
knowing all these I used the 3/32 scale on my ruler and sketched my outline.
Start with the luff. then set the compass for the throat/clew diagonal and mark the arc. measure the distance from the tack to the clew and mark where it meets the arc. Set the compass for the head measurement and mark down that arc. Then measure from the clew to the head and mark where it meets the arc, then connect that point to the throat.
Next mark your foot curve. Again consulting my book I made a foot curve 2 inches, the deepest part of the curve being directly in the middle of the foot.
The next thing to decide is how you're actually going to sew it together.
For the edges I went with cut tablings(I'll explain it later), 1 1/2 inches on the foot, luff, and head and 5/8 of an inch on the leech. To draw these on measure in from the edges.
How wide will the cloth between seams be? Usually this is dictated by the width of your material, but on such a small sail there's room to tinker. Most commonly cotton cloth is 36 inches wide, mine however was 44. I decided to make seams every 12 inches, I had to sew some false seams which complicated things a bit. The seams were 1/2 an inch wide. Draw these on your plan.
Will you be adding reefing points? I know it's pretty excessive and unnecessairy for a sail this small. But if you do, generally you'll want these to reduce the sail about 30%. For mine they would start 21 1/2 inches up from the tack and follow the curve of the foot.
Next thing to do is to design your patches. After looking at some different types I decided on traditional looking curved patches. A basic guideline is that patches should be 1 inch long for every foot of sail edge it is applied to.
Then mark where any metal or other hardware will go. Along the luff I've got eyelets every foot. There would be eyelets in each reef point. There is a brail eyelet, 50 inches down from the peak in the leech.
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