1) Craunch 2) Crunch 3) Grind 4) Press 1) Craunch 
• (v. t.) See Craunch.
It's the name given to the piles of stones which run perpendicular to the banks of the Humber at places like Paull. I can find no reference to the word other than as a variation of crunch. It has been used in the area for as long as I can remember.
Cranch transitive verb See Craunch .