The tankini is nothing more than the top half of a one piece. It is usually made with spaghetti straps, but there is no reason why you couldn’t have wider shoulder straps or even turn it into a halter. It is probably the simplest item of swimwear to make but you have to ask if it’s worth the effort to make a one piece block if all you want is the tankini. Many will make the tankini based on just a bust and length measurement, but I like tankinis to be properly fitted and darted for the bust … larger busts really need to be in an underwire (see the bra section – make a cup size smaller in lycra).
This lesson will create both the tankini (above) and the crop top (below) patterns using the crop top as the shelf bra. The tankini dart is curved off and the bust section of the front panel is gathered/eased into the corresponding section on the back panel. I would not gather the tankini without the shelf bra … instead leave the dart in if you don’t want the shelf bra. If you just want the crop top only then skip steps 3 to 8.
The Tankini
Step One
Trace around your one piece blocks. Draft a guide line for the garment hem about 5cm below the leg line at the side seam (red line). This is an arbitrary line and can be as low or high as you like but should really extend beyond the waist band of whatever bottom style you wish to wear with it. Consider that when you sit down the hem line will rise about 5cm and you still want it to cover the bikini bottom. That said some of my younger students like the hem line at the waist line so it’s really up to you.
Draft a guide line 10cm up from the bust point and square across to center front.
Step Two
Draft in the neckline in the style of your choice. Start about 3-4cm above the bust line at center front and curve upward to approach the strap point at 45 degrees. Continue down to the side seam making a right angle at the strap point. Your design line should cross the side seam at least 2-3cm above the bust line but can drop below the bustline slightly at center back. If you want to drop the center bak even further you should make the spaghetti straps cross over at the back. Note you cannot drop the center back so far if you want a shelf bra!
Step Three
Extend the side seams down to the hem line.
Step Four
You don’t have to do this step if you want a really fitted tankini, but I find that if you take some of the waist reduction out of the garment it doesn’t tend to rise as much (note all tankinis will rise over time given the chance and there’s nothing you can do to stop it definitively). The red line is another arbitrary position but take more shaping out of the front waist than you do from the back waist, making sure that your side seams are of equal length.
Step Five
Draft in your hem line such that it forms right angles with the center back, side seam and center front. If you’re designing for retail, ensure the hem is the same front to back, if not slightly longer at the back.
Step Six
Smooth a curve gently over the dart and notch the front and back pattern pieces so you know where to ease one panel into the other. If you arent going to make a shelf bra then ignore this step and leave the dart. You could lower the dart to a French Dart position if you want or even turn it into a princess line … the choice is limited by your imagination.
Step Seven
Retrace the panels. Be sure to clearly label your pattern with a title, panel name, size, cutting instructions, author’s name, date and revision number. Finaly, add seam allowance to the pattern based on how you intend to assemble it. I’ve shown this pattern with 10mm allowance for overlocked seams (8mm to blade, 2mm off cut) and 10mm for fold over elastics. Do not elasticate the hem line, simply fold over and cover stitch. I haven’t added seam allowance to the neckline because I would bind the upper edge and run the binding off the edge enoght to use it as my straps. If you don’t have a binder for your coverstitch machine then add seam allowance to the neck line and use fold over elastic and spaghetti straps.
Step Eight – Pregnancy
I often get asked how to modify the tankini pattern for pregnancy. It’s really easy. Simply rotate the section below the front waist about 10 degrees per trimester on average. Do not alter the back panel at all. If you are really enthusiatic, keep your pattern and rotate it back after pregnancy as there is enough fabric in the front panel to convert it back.
The Crop Top
Step Nine
Draft in the empire line (red line) about 8-9cm below the bust point (the underwire is represented to help you picture where it sits), making it intersect the side seam and center front at right angles. Continue this line on the back panel. If you were making only the crop top you might either narrow the back strap down to put in a bikini clip or widen the back strap for extra support. This should demonstrate why the neckline should not be lowered too far at center back!
Step Ten
Remove all the unneeded lines. Draft in a new guide square down from the bust point and rotate the dart closed at the side seam. Smooth off the curve at the side seam (red line).
Step Eleven
The top image is the crop top ready for a bikini clip. I’ve shortened the strap by 2cm to allow for the loss of tension due to narrwing of the strap. The crop top is bound all the way around so I’ve only added seam allowance to the dart and clip.
The bottom image is the shelf bra. It is stitched into the side seam (you ease it in like the back panel). Seam allowance has been added to the bottom for a soft elastic to go under the bust and tension the shelf into place. Notice I haven’t pulled the dart back for either the shelf bra or crop top … this is a support garment and it supports better at full length.
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