The cast-net is circular, measuring from six to eight meters in diameter, with bars of lead attached to the edge, and used by a single fisherman.  He arranges it on his right arm, and standing in shallow water or in a boat, throws it forcefully out on the water, where it lands like a parachute and sinks to the bottom.  The cast-net for big fish has a larger mesh and heavier sinkers.

There are two ways of retrieving the catch.  The fisherman may dive down to the net, pull the fish one by one through the meshing or out of the net and put them in a pouch.  Or he may dive and gather all the sinkers, lift the edges carefully over the stones, and take the net up into the boat with the catch inside.  When cast from shallow water, and especially if the catch is heavy, the net is dragged to the shore.

Information from "The Sea of Galilee and its Fishermen in the New Testament," by Mendel Nun, Kibbutz Ein Gev, Israel