Fishing Manhattan Beach Style

Greetings from California.  I visited the Manhattan Beach Pier yesterday and snapped a few photos.  The fishermen there have an interesting style of fishing live bait.  First, they cast out a sinker as far as they can and then attach the bait to the line and let it slide into the water.  The water looked to be about 20 feet deep or more so the live bait has plenty of room to swim around naturally.  The only thing I question is, how do you set the hook effectively with the sinker on the ocean floor and the bait somewhere in between?  I did not see anyone catching but the guys I spoke to said it works every time.