Fish-finder rigs use a snap connector with a nylon sleeve that slips over the line to attach a sinker, and they work fine for inshore species such as striped bass and red drum. But to get the same benefits out of the rig with deep-water species such as grouper and snapper, I replace the snap with a metal shower-curtain ring. The larger ring allows me to put one to three pounds of bank sinkers on the line. I bait the hook with a whole squid or mackerel and lower it down to the structure, keeping my reel out of gear, but using thumb pressure to prevent an overrun. When I feel a tug, I let up on the thumb pressure until about six feet of line goes out, engage the reel and set the hook.