Requirements:
4mm crochet hook
Darning needle
150 grams DK cotton yarn

Abbreviations:
dc double crochet
sc single crochet
sl st slip stitch
ch chain
st(s) stitch(es)
sp space
beg beginning
rep repeat
sk skip

Notes:
This item is worked in rows and uses 4 different colour yarns and changes colour every second row.
Hot water bottles don’t seem to come in a standard size or length. You may want to run a test swatch of crochet work in the pattern stitch to see how many stitches (chains) are required across the width to cover your bottle on one side only.
The cover is made up of two sides which are then joined together. We begin crocheting the cover from the bottom of the hot water bottle up to the top including the neck. This is then repeated for the other side. The shape of the hot water bottle starts off narrower at the bottom than it across the body of the bottle. It then widens for the body of the bottle, and then narrows again at the shoulders of the bottle, and then gets very narrow for the neck. It may or may not widen just slightly for the opening at the top.
The cover we will crochet will follow the shaping of the diagram opposite – increase from the bottom shaping to create the wider body, decrease again for the shoulders, and another sharp decrease for the neck of the cover.