The term "rig" or "rigging" is a generic one among anglers that refers to all things on the fishing line from the rod tip to the hook, and includes weights, snaps, swivels, beads, spinner blades, floats, dropper loops, hooks and stingers. More recently, the term "rigging" has been defined a bit, primarily by anglers who use it to differentiate between fishing with artificial lures and fishing with live bait. Today, if you are "rigging," you are using worms, leeches, minnows or other live offerings.
The simplest rig is a plain hook tied directly to the line and impaled in a minnow or worm. Left to sink slowly or drift naturally in current while feeding line manually to eliminate any drag, this simple rig is one of the deadliest for a variety of species. It's also tough to cast, tedious to fish and allows a limited amount of water to be covered.
That's why anglers started tying "rigs" incorporating sinkers, dropper hooks, floats, three-way swivels and spinner blades to allow their terminal tackle to be cast, trolled, and drifted with more control, color, sound and action to attract fish to the bait.
Simply adding a split shot or two a foot or so above the simple hook-and-bait setup may be all you need to create a rig that you can cast and sinks quickly to a fish's feeding level. Thread a couple of beads and a spinner blade on the line above the weights and you have a classic spinner rig that adds flash and vibration to the offering, which you can troll, cast or drift.
The classic "rig" for bottom fishing for species such as catfish, stripers, trout, carp and many coastal saltwater gamefish uses a sliding sinker threaded onto the line. The line is slipped through the sinker and tied to a barrel swivel to keep the sinker from sliding down onto the hook and to allow for a separate length of line to be attached to the hook. A piece of line 18 inches or so long is tied to the other eye of the swivel with the hook knotted to the other end of that line, creating what is called a "leader." Often, that leader is made with line with a breaking strength testing less than the main line, so that if the hook snags, the leader breaks before the main line, saving the swivel and sinker.
The sliding sinker is made to allow the line to slip freely through it so that when a fish picks up the baited hook, it will not feel the weight of the sinker when it swims off. Egg sinkers are molded with a hole through their middle through which the line can slip; dipsy and pyramid sinkers feature an eye of brass wire. In fact, there are a dozen or so types of sinkers designed for bottom fishing, made to hold bottom in a variety of current and bottom situations.
Tandem rigs are fished vertically beneath your boat or dock, and allow you to fish baits at two or more depths at the same time from the same line. These multi-hook, multi-depth rigs are popular with crappie anglers and fishermen seeking panfish and other species that school up under and around a structure that is hard to cast to and retrieve through and is great for anchored or dock boats because it's a strictly vertical presentation targeting species virtually underfoot.
Tandems use loops or wire arms tied into the line at various places to which leaders and hooks are attached. The end of the rig is fitted with a snap swivel to allow it to be attached to different size dipsy sinkers to allow the weight to be changed to match the conditions.
By dropping the rig until the sinker hits bottom and reeling in until you can feel the weight making contact, the rig will allow the leaders to hold their baits at the various levels they are placed along the main line. You can also lift the rig to target fish that may be suspended off the bottom at a variety of levels.
You can fish a tandem rig beneath a bobber and cast it, but the bobber size required to float the sinker at the rig's terminal end usually has to be fairly large and it makes hanging the rig cumbersome, but it can be done. Most tandem rigs are fished with the rod in hand so that the angler can react at the first nibble. When the fishing is really fast, you can catch multiple fish at a time on a tandem rig.
Three-way rigs are made for drifting and trolling to offer a moving bait and to cover more water. They feature a "Y"-shaped swivel with three eyes: one for the main line, one for a leader and hook, and one for a short length of line fitted with a weight. The three-way rig allows you to maintain contact with the bottom while the boat is moving by letting enough line out to feel the sinker hitting the bottom occasionally. The rig keeps the baited leader and hook up and away from the bottom at a distance determined by how long you make the weighted line.
Some anglers add a spinner to the leader or use a worm harness on the working end of a three-way rig. A three-way rig can also be used with artificial lures to get them down to where the fish are.
As with the bottom rig, the weighted line tied to a three-way rig is usually weaker than the main line so that in the event the sinker snags, its tether will break first, leaving the rest of the rig intact. One trick when fishing a three-way rig in snag-infested waters is to use spit shot lightly pinched onto the weight line. That way, when a split shot hangs-up it will slide off the line with a little pressure rather than forcing you to break it to free your rig.
And as we've said here before: if you're not snagging occasionally, you're probably not fishing where the fish are!