Shrimping Question

[Ray]

Freezers and IQF boxes are different animals.
There is salt boxes that hold high concentration of saltwater. When you shovel the catch into the salt box, most everything floats to the top except for shrimp and crabs, due to the high concentration of salt. Then you just dip net the fish and other things that float up to the top and throw overboard. The rest at the bottom is usually just shrimp. Makes culling a lot simpler and gets the shrimp on ice faster than hand culling.
IQF box is an insulated box with freezer plates towards the back and some kind of circulating mechanism to circulate the water. They add around 8 lbs. of salt per gallon of water, or something like that. The saltwater won't freeze, but it will form a slush at -20 deg. F.
After the shrimp are culled and bagged in onion sacks, they are dipped a couple times in the IQF box. The high salt keeps them from sticking together, it forms a layer between each shrimp. The sack is hung for a couple minutes to drip, then put in a freezer below decks.
I have worked on a few IQF boxes, each shrimper makes them different. I have seen some 500 gal. stainless steel tote tanks used inside walk in freezers so they won't have to insulate them, but the shrimper has to work in the freezer.