I designed this baby blanket for my great-niece several years ago - gauge is not important - based on inches; you chain to get the size you want, in multiples of 2, then each row is same pattern repeat of half-shells

You will need at least 920-1000 yds of size 3 weight yarn - you can use any weight, just increase the yardage

Yarn for basic blanket
Yarn for trim/border (optional different color)

size J hook (or H if you crochet tight)