I kept digging in the stash in the boxes I knew contained superwash yarns, and after a good search, still had nothing. It took going to the box of things that were more than just bits and pieces, to find exactly the right thing. I found some Cascade 220 Superwash.
I only had 1 part ball each of green, ecru and burgundy red, so I picked one up and started to knit. I cast on 36, because the first pattern I worked off of said to cast 40 in a dk weight yarn, and this is just slightly heavier than a dk weight. (If you wanted to follow this, it was a 3.5 mm needle)
And then I just kept knitting till I felt like adding a little colour. I did that for a while and then knit some lice, and then another perrie pattern. By the time I got to the second peerie pattern and I was worried about running out of the ecru, plus I was starting to be concerned about the decreases.
Turns out that winging it and knitting blind worked! I did not run out of yarn, and the 10 centered double decreases I used every row, perfectly mimic the shape of the hot water bottle. I knit a little ribbing for a collar on the remaining stitches and voila. There you have it.
1 hot water bottle cozy in a good sturdy soft superwash yarn for Daughter3, whose back hurts pretty steady with the babe.
Next up, some spiderman socks for a little guy.