When fishing from a boat or shore I use your typical heavy gear for catfishing. A Penn 309 reel spooled with 40 pound test on a short heavy rod usually does the trick. For terminal tackle I usually use a 60 pound mono leader with a 7/0 - 9/0 hook on a fish finder rig with 8 -12 OZ of weight. This will handle any catfish in America.
In fact, it is the rig I caught this monster on:
When fishing from a kayak, you are a little more limited.
First, you do not need a big reel. A quality reel with a nice drag is all you need. I like the Abu Garcia C3 line. A big fish will haul you around more than you will haul it, so you don't need to worry about it pulling a lot of line off your reel. Also, most of your fishing will be done by simply dropping the line over the side of your kayak or with short, precise casts. Long casts are rarely needed.
One feature that your reel should have is a clicker. This allows you to set your reel to free spool. The clicker alarms you when something takes you bait. This is important because you never know how big of a fish is going to take your bait. A very large fish could break your rod holder, or even capsize your kayak if it takes the bait and runs while you have the drag locked down. This risk can be mitigated by using light line, but using a clicker is always the better choice.
A heavy fighting rod is also not ideal. Something with the strength and action of a musky rod is perfect. It needs to be small enough not to be cumbersome in the small constraints of a kayak, but stout enough to handle a 50+ pound fish.
Line should be lighter than normal also. You do not need super heavy line because in a kayak you fight the fish instead of horsing it in. It is amazing how large of a fish you can land with light line in a kayak. I never use anything higher than 20 pound test. The reason is mostly safety related. I want the line to break if it gets snagged and I am caught in a current or if the fish is too big. It is possible to hook a 100 pound fish in my waters. There is no way a person at my skill level could handle a fish that big in my 'yak. It would be dangerous.
I target fish in the 30 -50 pound range. 20 pound test is plenty for this size of fish.
Here is the terminal rig I use:
It is a 5/0 - 7/0 circle hook attached to an 80 pound mono leader. The leader attaches to a barrel swivel which attaches to the main line. A fish finder slider attached to a 2 OZ weight goes on the main line above the swivel. A bead protects the main line knot from being damaged by the weight.
I like to use a Snell knot to attach the hook to the leader. This seems to work better with heavy line.
Speaking of heavy line, I use 80 pound for one reason only. It is thick. Try dragging a 20 pound fish on your kayak by grabbing a 20 pound leader. It hurts! Now double that. Thin line under strain turns into a knife. I get cut all the time fishing. Never from a knife, always from line. 80 pound test gives me more to hold on to when landing big fish. It is simple as that.
The leader attached to the swivel with a clinch knot (not an improved clinch knot). The clinch knot works better than the improved clinch on heavy mono.
When purchasing fish finder sliders, look for these blue ones. They seem to hold up a lot better than the yellow, snap on ones.
A 2 OZ weight seems perfect for keeping bait down when you are simply dropping and drifting. Sometimes I use less, sometimes more. It just depends on how fast I am drifting and how deep I am going.
The bead is just a plastic bead.
There you have it. This is rig I use for hunting river monsters on the James in a kayak. What is your favorite rig?