How to make a mermaid's tail

I defy anyone to come up with a more daunting request for a costume than: "I want to be a mermaid, mummy!" I Even a novice can see that the challenge lies in making a mermaid's tail that won't send the mermaid to casualty once she starts to run in it.

For once, Google was less than helpful so I had a bit of a doodle and came up with this.

It's a less than spectacular drawing but you get the gist. And this is how it translated into fabric.

Requirements: 1.5 metres of hologram satin or medium weight vaguely fishy fabric

1 metre of satin lining for the fins

1 metre of lame/organza for the fins

1/2 metre of nylon chiffon for the seaweedy trim

1/4 metre of ribbing for a comfortable waistband

1/4" elastic. - about 50cm.

Waistband elastic - as much as you need to fit

1. Take your mermaid's measurements - waist, waist-to-floor and waist-to-knee. On a very large sheet of paper, draw a rectangle where the width = the waist measurement divided by 2, and the length is the waist-to-floor measurement minus the width of the ribbing.

2. Draw another line a few centimetres outside the right-hand length line and attach it at the top to the waist line with a sharp curve. The picture explains this better. The outside line is the side-seam and the curve makes a nice fishy shape once it's sewn. Put in the fold lines on the left-hand line and you have the back panel of the skirt. Cut it out and trace around it onto another sheet of paper.

3. For the front panel mark the waist-to-knee measurement on the fold line. A couple of centimetres down from this mark, do a curved line to join the fold line to the bottom of the side-seam. This forms the scoop of the skirt.

4. Fold the fashion fabric in half along the grain and cut out 2 x back, adding seam allowances as you cut. If your fabric is inclined to fray then do good wide seam allowances so that your stitching will be last longer. Then put the front pattern over one of the (still folded) back pieces and cut out along the scoop line (no need to add seam allowance). Keep the scooped out fabric piece for use later.

5. To make the fins you need to cut out a rectangle of satin lining about 50cm long and the same width as the bottom of the back, seam allowances inclusive. Then cut diagonally across the rectangle like in the picture.

Do the same with the fin fabric and put them and the lining pieces to one side.

6. It's now time to start sewing. First construct the fins. If you are using the kind of nylon/poyester organza that I used, you will need to stabilise it by sewing each fin to its respective lining. Believe me this will make things a lot easier for you when you come to join them all up. Just place the fin fabric face up on the top of the lining, pin them together and do a row of stitching just outside the seam line along the four sides. Do the same for all four of the fins. Then put two fins together RS to RS and stitch them together as normal, leaving the top straight edge unsewn. This is the side you will be attaching to the bottom of the tail. Turn the fins the right side out and do the best job of pressing them you can, given how horrible the fabric is. Top stitch to help them hold their shape.

7. To attach the fins: Finish the curved edge of the piece you scooped out from the front. Sew the fins to the WS of the bottom of the back, with the fins pointing up towards the waist. Press seam allowances towards the waist. Using a 3-step zig-zag sew the 1/4" elastic along that seam allowance, pulling the elastic to its utmost as you sew. This will gather the fins. The easiest way to attach the scoop is to fold over the bottom edge to make a hem. Press in place and then sew it in place over the elastic with a zig-zag stitch, pulling the elastic & fins taut as you sew. Top-stitch the scoop in place along the curve.

8. Hem the front of the skirt. I did it with a narrow rolled hem. Sew the side seams RS together. My fishy fabric frayed like mad so I overlocked the seams first and then seamed them again a good centimetre in from the edge.

9. If you are going to do drapey seaweed, cut four spirals from the nylon chiffon. Cut a circle about 20cm across (I eyeballed it with a rotary cutter). Then cut into the circle in a spiral shape - it dosn't have to be absolutely perfect. Stitch them in place along the top.

10. Attaching the waistband. Decide how deep you want the waistband - it's better if the ribbing casing is just slightly wider than the elastic. Cut the ribbing to (2 x desired depth) plus (2 x seam allowance). If the ribbing isn't tubular, seam it into a tube. Gather the waist to fit. Attach the band to the waist RS together with a zig-zag stitch. Fold ribbing to inside and press. Top-stitch in place catching both layers of rib, leaving a gap to insert the elastic. Push the elastic through with a safety-pin and sew ends together. Sew up the gap. You're done!

I attached a D-ring between the fins so that Laura can carry the tail on a bangle for when she's outside.

For the top I used Ottobre's Floral Top pattern #7 from 02/05. I lengthened it, added a chiffon ruffle and elasticated the back. It's cute and age-appropriate.

If you find this tutorial useful, please consider giving a donation to MacMillan nurses.

In memory of Aileen Driffield, who loved seeing Laura in her 'too many dresses' but missed this one