The pattern I ended up using is below (I'll go into adjusting it afterwards!)
- ch in groups of 20, plus 2 turning chain
- skip 2 loops, 2dc into next dc
- dc in each loop x 6
- dc3tog x 2
- dc in each loop x 6
- 3dc into dc
Turn, ch 3, repeat steps 2-6 until your blanket is the size you want! Simple. The only thing that can be fiddly is doing the last 3 dc into the top of the ch3, so make sure you are using that as the last stitch or your blanket will turn into a triangle!
If you're doing stripes like me, two rows per stripe is my personal preference so each stripe has both the front and back of the crochet stitch. Just looks neater to me! (The yarn I am using is Drops Cotton Light, which is one of my favourites, and I have an accident every time it's on sale at the Yarn Warehouse.)
Below is what this pattern looks like written down (in my messy handwriting - I couldn't find a free crochet diagram program, hope I used the right symbols!) Each ripple consists of a decrease, two straights, and an increase, which is often split like this so your finished piece of crochet has lovely neat ends. The row of loops at the bottom is the number which you should chain in groups of, in this case, twenty. (Remember to chain 2, as this counts as the first dc of the increase.)
For each increase and decrease, I am working in threes. If you want a gentle ripple, you can adjust this so you are only ever crocheting two stitches together, or increasing by one stitch at a time. If you do this, you'll need to subtract two from the number which you'll be doing the initial chain in groups of. Just make sure that the increase and decrease match.
As for the straight sections, you can make these longer (which will mean you need to add groups of two to the chain number) or shorter (subtract groups of two from the chain number.) Just remember to keep them equal, or your ripple will be wonky.
Play around with some ripple swatches and see what looks best to you! :) My ripple blanket is hopefully going to be about the size of a single bed, if I've estimated yarn amounts correctly, so you'll probably be seeing more of it, including my adventures in making a ripple blanket border. I've got a lot of excellent netflix watching lined up for my blanket-making time!