I promise that my explanation won't be as long as Polo's cause he just about covered all bases.
Here goes: Have you ever shot a slingshot as a kid? Well, shooting docks or underneath overhanging trees is a technique that makes presenting lures to Crappie or Bass easy and a whole lot like shooting a slingshot. In the winter time when the water is down, of course, I don't have to fish from my knees. But in the summertime when Gator takes you crappie fishing, it is imperative that you fish on your knees. Just kidding, Gator.
The reason that I prefer shorter rods than Polo is because I get up tight to the docks many times. There will be times when the wind will blow you into the docks and is such an aggravation that you can't fish it properly. Polo has missed several opportunities lately because the wind wouldn't let him fish the mainlake docks that he wanted to and knew that fish were on them. With shorter rods, you can get close to the docks and still shoot underneath them without worrying about breaking your rod tips on the hookset or the actual cast. I have let the wind keep me uptight against a dock and by getting on your knees, you can still hold the rod low to the water and shoot the jig back to the fish. Troublesome yes, but still possible to fish.
My rods are cheap. Shakespeare Micro graphite 5.0 UL's that have 5" from the tips removed per Fat Albert (greatest) $14.95 from Walmart. My reels are not cheap. I have a Quantam PT20 reel on one rod and Abu Garcia Cardinal 101 reel on the other. My favorite is the Cardinal 101. The next reels that I buy will be Cardinal 102's and/or 103's. Around $33+ at Walmart.
If you are not fishing Mr Crappie Hi-Vis yellow line, then something has to be wrong with the little noodle that is sitting on your shoulders. I fish with 4# test under docks, and I have grudgingly moved up to 6# on longer rods for Spot fishing at the Riverpark. You cannot find a better line for Crappie fishing than this. Order it from BPS for around 6.95 for a 3100 yard spool. Put the line in your freezer if you get it in bulk. That is a great tip for all you fishermen. Monofilament degrades at room temp, but retains its original strength if it is stored in a freezer. We have done numerous aging tests on nylon at Dupont where I used to work in the R&D lab.
One last benefit of using the slingshot method of delivery. Ever fish in the spring when the wind was blowing (when does it not ever blow in the spring) and had trouble with your accuracy? Using the slingshot method of delivery keeps the lure under the wind and on target. I use it all the time even in open water even if the wind isn't blowing. I just love to cast this way. Never gets your shoulders tired or achy. So I sacrifice 10 yards of distance from time to time. Who cares? I still catch my fair share of fish or more if it is windy enough, cause I will be on target more than a overhead caster will be.
I need to look back and see if my answer is longer than Polo's. Goodness, this gets good when you start talking about it. emoBigsmile emoGeezer
One final comment. A flimsy action spaghetti noodle like UL rod isn't good for this type of fishing. The rod needs a little backbone and when I had FA break off the tip of the rods that I use and put new tips on them 5" shorter, it stiffened up the rods just right, but still left a good fast tip so sensitivity wasn't compromised.