Here you go Paul (Jul. 2007):
About 25 years ago, BASSMaster magazine ran a series of articles on monofilament line testing. Now we see line tests in magazines and online quite frequently. However, the neat thing about these tests were some of the variables covered that you don't typically hear about. In one particular test they documented transfer of energy through monofilaments at different distances using two different line ratings.
The test setup was basic but neat. Attach one end of your monofilament to a gauge down in the water at depth and then have a person set the hook at different distances and see how much energy is transferred to the hook. They did this with 8 pound and 20 pound monofilaments. They found several things. One was that as distance from the hooksetter increased (i.e. a longer cast), final force at the hook decreased. The closer the "fish" was to you when you set, the more force you delivered to the hook. Another was that 30' was the crossover point between the two different pound test ratings. In other words, at 30 feet, the force exerted at the hook was identical between the 8 and 20 pound test lines. The further you moved out past 30 feet, the more the advantage of using 8 pound line increased. Anything shorter than 30 feet and the 20 pound mono resulted in more force at the hook.
They explained this via stretch and the "bow" effect. The heavier the line the less the inherent stretch. However, this is overcome apparently at the 30 foot mark. This is then explained by the "bow" effect, basically not having a straight line to your bait at distance. You cast, the bait sinks, but it has to drag the line with it. Eight pound test being thinner, is pulled more easily through the water column and subsequently gives you a more straight line to your bait resulting in better transfer of energy, to the point of overcoming its stretch bias.
Kind of interesting and a little eye-opening. To this day you'll still hear people refer to these explanations when talking about the subject of lines and hooksets, though many of the materials have changed (braids, fusion and and fluorocarbon). After all this time though, I realized there was also one explanation I never heard given or considered. Maybe someone at some point has thought of this, but I haven't come across it yet in all my readings.
That is the factor of surface area. Every line for a given length has a given surface area. The longer the length of line in the water, the greater the surface area. This surface area has a resulting amount of drag. You have probably experienced this before and just never thought about it. Have you ever let a bunch of line trail off your spool into the water and trolled it behind your boat to undo line twist? Notice how the more line you let out, even with no bait attached the more your rod starts to bend because of this drag? Enough line out and it can feel just like winding in a fish or heavy object.
The chart attached (click for full chart) gives you the surface area in square inches for a given pound test/diameter of line and a given length of that line in the water. Double the diameter of your line or double the distance of your cast and your surface area increases proportionately. Now imagine the difference required to catch a bass that eats your bait at 80' on 14# test line versus one caught finessing off a bed on 6# test at say 40' distance. Surface area of your line is tripled and that resulting difference in drag has to be overcome. Just something to think about the next time a fish clears the air on a long hookset and throws your bait