Vintage pattern: French Sailor trousers

Sailor trousers, Italian and French
Italian sailor trousers on the left, tummy-covering French sailor ones on the right.

It took me considerable time to prepare this tutorial, since I wanted to make it as clear and easy to follow as possible, but there’s still a lot of technical details: if you’re not in the least bit interested in pattern cutting, you’d better off finding someone to do the job for you (me, maybe?).

Also, to avoid the information overload, I’m doing this tutorial based on my own measurements and on my body type. I didn’t alter the original vintage too much, so you can make this pattern as an addition to your own library of basic blocks - just remember to make the trousers longer, as I’m quite short (1.60m/ 5 ft. 3”).

French sailor trousers - technical overview
French sailor trousers - Measurements and some construction details: not quite a tech pack that you can send straight to the manufacturer, but enough to start talking with your pattern cutter or sample maker

Tracing the pattern guidelines

Back when I was in Bunka Fashion College, making a garment started with a lot of math and geometry, plus a thick textbook and our teacher doing every step on the blackboard with a set of giant rulers.

From Bunka Fashion College - Skirts and Pants textbook

It took us about a month to complete the trousers module of the course, and we had already learned the fundamentals of the Bunka way of doing things at that point, so we could handle all that’s happening above.

I never had to make patterns from scratch like this again when I started working or when I was at Central Saint Martins, since it takes too much time: it’s much more effective to either copy the pattern of a vintage piece or quickly draft a new pattern straight on calico or another cheap fabric using pattern blocks of basic pieces.

Still, I find it helpful to use some of the techniques I learned at Bunka to draft a few guidelines to copy a pattern:

French sailor trousers (open, upper part)
Trousers pattern draft (upper part)

This will make it easier for you to trace the pattern with your measurements, instead of mine (Waist = 64 cm; Hip = 92 cm).

I think most people won’t know their Waist to Hip and Hip to crotch measurements, so as a reference:

  • Me (1.60 m height): Waist to hip = 20 cm; Hip to crotch = 6.5 cm;
  • Recommended for a size S/ French 36/ Italian 40: Waist to hip = 21.5 cm; Hip to crotch = 6.5 cm;
  • For every size up: add 0.5 cm to each measurement.

How to trace the actual pattern

So you got all those measurements and traced a little square with your guidelines. Great!

Now you’re ready for this:

French sailor trousers - pattern draft

Let’s go over the details, and if you’re still with me I recommend you print out the image above so it’s easier to follow and also write your own notes:

  • Waist to hip, Hip to crotch and Hip measurement: already determined when tracing the guidelines;
  • Measurement at Crotch line: either make it 1.2 cm wider for each size up, or use your thigh measurement as reference: mine is 56 cm, so there are extra 10.6 cm on my trousers - which you may not need;
  • Front and Back hip measurement difference: 2.4 cm on my pattern, add 0.5 cm for every size up;
  • Front and Back dart placement: move them away from the Centre Front/ Back as the waist size goes up;
  • Side length: measurement from your Waist to the floor. 99 cm is appropriate for my height of 1.60 m, you may need more or less;
  • Measurement at hem (hem circumference): 75.6 cm is already wider than what most brands sell as wide leg pants, decide how much you want yours to flare;

This is the main pattern that you will alter if you want to make different sizes, or create a different silhouette (straight leg, slim, add more flare etc).

Moving on to the other parts, starting with the easiest:

Waistband: wider on the Front, and 5 cm longer on the Left side = the side going underneath when the trousers are fastened;

French sailor trousers - pattern (waistband)

Once you’ve added the seam allowances, your patterns should look like this:

French sailor trousers - main patterns
Tip: add notches on a few strategic places or on as many as you need to help you when you’re sewing.

With the leg and the waistband patterns, you can already cut and make a pair of trousers in calico to quickly check the fit - just cut a larger seam allowance in case you have to make them slightly larger after fitting.

Tracing the last parts: pocket bags and facing

Since these trousers don’t have a zipper, and the waistband is not sewn to the trousers on the Front, the pocket bags will also work as a facing/ extension of the waistband.

French sailor trousers - pocket pattern draft

After adding seam allowance, the patterns should look like this:

French sailor trousers - pocket patterns

Pocket bags: wider on the Left side, like the waistband, no seam allowance on the bottom if you’re doing the same overlock finish as my trousers.

I made separate patterns for the bottom (inner?) pocket bags to add a wider seam allowance on the side, that will cover the dart seam better than on my vintage trousers:

French sailor trousers - pocket patterns

Facing: added 3.9 cm to the side = welt width x 2 +0.5 seam allowance.

French sailor trousers- front flap and facing
French sailor trousers - facing and welt how-to

Finished! Oh, wait…

I forgot to mark where the buttons should go. Follow the video for this and more details on how to make the trickiest part: