Rob, explain the physics behind this please. It makes no sense to me. I would say use the heaviest tippet you can get away with. If I have an 8 weight rod and a 3 weight rod with the same tippet, and I hook a fish with 40 feet of line out and I don't allow any line to come off the reel, then when I reel or strip in 5 feet of line, the fish is now 35 feet out. With both rods. It may be harder to pull in the 5 feet of line with the lighter weight rod, but I am not prevented from doing it as we are not talking about a 50 pound fish. The reason I use heavier rods is that it easier to toss my bigger flies, or because of the wind. Using your logic, we should all be using 3 foot,12 weight rods to horse the fish in quicker.
Teach me please.
I think technically, you'd want a 12' 12 weight rod. You'd have better leverage that way.
Anyway, I was curious about your question of physics, so I went to the obvious source - chatbot GPT.
Here's what I got:
Hooke's law describes the actual physics of how a fishing rod bends in reaction to a force being applied.
Here's the equation:
F = -K * X
F is the force applied by the fish
K is the spring constant, or the stiffness of the rod
X is the displacement, or how much the rod bends
Lower K = softer rods, require less force to bend.
Higher K = stiffer rods, require more force to bend.
If the fish applies a force of 10 (arbitrary unit of measure), we'd apply a force of -10 (F), the soft rod (value K=1) will bend a lot (X=10). However, if you have a fish applying a force of 10 with a stiff rod (K value of 10), the rod will barely bend (X = 1).
As long as the rod stays within it's breaking point (elastic limit), you can see that you'd be able to absorb more force from the fish, tiring it out quicker with a stiffer rod, since it would take the fish more energy to apply more force. The faster the fish uses it's energy, the faster the fish will get tired to the point that it can be landed. With a stiff enough rod, an angler could conceptually land a fish before the fish is even tired from the fight (reference tournament bass anglers). Where as with a lighter rod, the fish could apply less force and get the rod to the breaking point quicker, and thus prolong the fight unnecessarily because it's using less energy to swim away from the angler.