A rigging needle is simply a needle used for rigging bait to help aid on offshore fishing such as: Trolling, Kite fishing, or live-bait fishing. One end has a hole where the thread is placed while the other end is sharp to be able to penetrate the bait/lure body.
How to Rig the Bait
Of course, there are many different ways to rig your bait, lure, etc. In general, you have to understand that something that you are about to rig to the line. What is it made of? Does it have a head and a body? What is the shape and type of its head? These are just some of the things you have to deal with.
Learn when to use a leader and what leader to use. Select the bait or lure. Cut several pieces of bow string (or other sturdy string), prepare strings as many (or more than) as your lures/baits. Get some pieces of Dacron or similar material. Glue all these stuff together and use a rigging needle to stitch them securely, making sure to arrange them in such a way that you will maximize your chances of landing as many fish as you can.
There are needles readily available, though you can also make your own.
Making Your Own Rigging Needle
What you need is a piece of wire coat hanger, file, hammer, and a drill with a 1/8” drill bit. It is quite simple to improvise a rigging needle. First, untwist the coat hanger and cut off a 12” piece (make it shorter or longer, depending on your bait; 12” is good for rigging eels). Use a file to sharpen one end. Use the hammer to flatten the opposite end. Drill a hole in the flattened portion and that’s it – you’ve just finished making your own needle.