Theres two main rigs to use, first is easy, a three way swivel top end to your mainline, bottom to about 12 inches of lightish line and a wieght (or stone), the third horizontal to slightly heveier line and a strong hook, a small mustard viking or simalar, then use crab, fish, worm or even limpet baits. Casting between the rocks and if you can a very very slow retrieve can help them get on the feed. But you will lose tackle. If you're going to be casting more than 20-30 feet a rottom bottom will need to be added, or hevier wieght link line.
The second is a standard sliding float setup which I prefere as it gives you more to watch and if there's any gar, macks or bass about they might take it too.