He doesnt mind wearing coats at all, which was a surprise when I first put it on him. I "drafted" a pattern for the coat from Troy's measurements. It was very simple to do. It took an hour from measuring to completion. I based the design on horse blankets. I didnt want a coat that I had to insert Troys legs into sleeves as he would have hated that. I didnt waterproof it, but Im sure you could.
To make one measure:
a: center of chest to how far back you want the coat to reach on the dogs back
b: between shoulder blades to how far back you want the coat to reach on the dogs back (the same place you measured to on the back in step 'a' measurement
c: between shoulder blades to how far down the belly you want the coat to reach
d:between shoulder blades to center of dogs chest
e: bottom of where neck meets chest to spot level with where you decided the coat would reach on the belly as in step 'c' measurement.
Argghhh stupid photobucket resized the image so you cant see which is a,b,c,d etc. Oh well I think you can figure it out reading the above measurements.
Next add seams allowances to your measurments and draw the pattern.
Then create a curve at the back and the neck line of the pattern.
Cut fabric and lining with measurement 'b' on the fold. Note: this doesnt allow for a lot of space around the shoulder blades/base of neck area. So if your dogs needs more room there create a pattern that will have the 'b' line curving upwards as it approaches the neck to allow more room. This adjustment will not allow for the pattern to by cut on the fold, instead cut out two pieces and sew down the centre back seam.
Sew your lining and fabric right sides together leaving an opening for turning. Slipstitch the opening closed.
If your fabric and linging are too bulky to turn then sew them wrong sides together and add a binding or trim to hide the seam.
You will need to create a belly strap by measuring under the belly. Sew one end to the side of the blanket and velcro to the end of the strap and velcro to the side of the blanket where you will attach the velcro end of the strap. Also sew some velcro on the front chest closures.
hope that helps.