Couple years ago I was kayak crabbing in the Severn and a DNR fellow checked me out. I had my keeper crabs in a basket with a noodle around it to keep it afloat with a line tied to the anchor at one end of the trotline. Not sure what the law is on this but That DNR officer was fine with my setup. In fact he said he was checking me out because he was thinking about doing the same thing and wanted to see my setup.
Used to be an everyday thing, to put a bushel basket in a tire inner tube and float it behind, while soft crabbing in the shallows.
In the basket went peelers, soft crabs and hard crabs. Now female soft crabs and males hard crabs can't be in the same basket.