Spider rigging for crappie is a very popular and extremely productive way to catch crappies. Spider rigging very popular in the southern US where multiple rods per angler are legal. Here in Minnesota spider rigging is not legal unless you use one pole / line per angler. So be sure and check your states regulations before considering this method. A spider rig starts with a slightly curved bar about 6-8 foot in length (where the poles mount) .
On the bar there are 8-12 rod holders that will hold rods and will fish over the front of the boat. You fish with no more then 4-5 rods per fisherman. If two people are fishing they would use at most 8-10 poles. More then 8 poles can get too much to manage. Multiple hits with fish on are very common. Yea, sounds like a lot of fun. You mount your rods in the rod holders using half the poles being 16 feet and half being 12 feet. Yes these are specialized very long cane pole type.
Rods (only having a reel where a cain pole would not). The rods when placed in the rod holders are in a semi circle fishing in front of the boat. With a spider rig you are simulating a school of baitfish barely moving along. You are moving at such a slow speed you can hardly perceive you are moving at all. Keep your trolling motor at a very slow speed. You do not need 8-10 poles to spider rig. The poles do not need to be a 12 or 16 feet long. You can just as well fish 1 rod per fisherman or 2. The rods could be 7 to 8 feet.
How to rig a spider rig. Use a 3 way swivel with two six inch pieces of line. One piece will go to a jig, the other piece will go to a ½ to ¾ ounce sinker. For the jig you can use any of the popular crappie jigs such as a beetle spin. You can rig your jigs with plastic bait, twister tails, minnows, or a power bait such as gulp alive.
Adjust your rod holders as low as they can go without the tip of the rod hitting the water. Depths to fish. You Want to fish just above the schools of crappie you are fishing. Twelve to 14 feet are good depths to start at. Adjust your depth and your fishing to the day you are fishing and what depths those crappie are at. Use your LCR or depth finder to note the depths the fish are at.