If the pattern you’ve chosen does not have a back fastening, you can add a supportive bra back for your swimsuit very easily. This bra-back keeps the suit on your shoulders while swimming, which makes it an ideal addition to the suit of competitive swimmers. The fastening can be placed high toward the shoulders and neckline (often called a racer-back) or can be even with the bustline at the lowest placement for bra-like support. All the variations can use a g-hook or a swimwear clicker. The drafting process is the same for any of the variations shown below.

To draft this style, you need to trace the back pattern piece. Start by marking the seamlines in 3/8” (9 mm) from the edges along the centre back and the strap. Mark the DoGS on the pattern piece.

Draw two vertical lines – one along the innermost curve seamline and the second at the outermost curve seamline, perpendicular to the DoGS line. Then, draw a horizontal line parallel to the DoGS 1/3 of the way between the waist and the underarm seam (approximately the bottom of the bustline) as shown below. That horizontal line marks the centre of the fastener.

Mark two short horizontal lines, one above and one below the fastener line between the two vertical lines. Each short line will be away from the fastener line by a distance equal to half the height of the fastener you are using. If your clip has a 1” (25 mm) slot for fastening, each line should each be 1/2” (12.5 mm) from the horizontal balance line. Connect the two lines at the outermost point.

Draw a curved line from the seamline on the back strap scoop to the top short line. This is the top of the bra-back extension.

Draw a second curved line from the bottom short line around to the top of the back scoop. Do not curve inward more than one-third to one-half of the total width of the original back, otherwise the back will not lie smoothly against the body.  The dotted line is the seamline of the new racer-back.

Add the seam allowance of 3/8” (9 mm) to the curved lines. These curved edges will be finished with elastic during construction. When finished, the fabric tail will feed through the slot on the clip and be sewn down.

The finished draft will look similar to drawing 1 below. Drafts for the other versions (the high and the medium position) are done the same way, except the curves are further up on the strap. The lower scoop should be no more than one-third the width of the original pattern piece; otherwise it will not lay flat to the body. You can raise the centre back seam (shown in the drawing 3) for more coverage if you want.

                                                                                            1                                                                   2                                                                 3

It is not at all difficult to add a supportive bra back to your swimsuit. I hope you give this a try!

2 replies
  1. Carol Stephen
    Carol Stephen says:

    I FINALLY got my suit done. I did the full bra with the bra back with power net insert. It is the BOMB. I can’t believe your pattern fit me so easily! Thank you !!!


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