If you're fishing from a boat just tie off the cans on the boat cleats.

We use a modified deer feeder to keep the cats around. A chute was rigged so
the corn/dog food goes into the water and is not dispersed 360 degrees. It
drops about 8 ounces at 5 o'clock every day. We fish about there twice a
month. Nice 2-3 pounder channel cats.