my method is to blend old baits and fish bits from the freezer(thaw first) to a fine paste, then fill zip lock bags 6''x4'', whilst filling add a few stones to ensure it sinks and stays put on the bottom. re-freeze until needed. when fishing (at anchor) cut the bag of and sporadically throw one in front of the boat so it settles under the stern where the baits will be. please note this is a shallow water method. just my two pennyworth.