Reel Repair by Alan Tani

so was using a spring scale to set the drag on my 2 speed.
rod is 7' med-heavy (unknown blank-Killer Stix) from Hubbard's Marina [near clearwater)
scale indicated drag was 10-12 lbs. OK

i put 10lbs of weight on the line, and it bent the rod like nobody's business.
yes, it was a similar bend to what the scale indicated, but i don't remember a 10lb.
red snapper doing that.

my question, is 10lbs. weight above ground the same as pulling on a 10lb. fish underwater?
does the specific gravity of the fish (underwater weight including buoyancy) change the equation
from the same bend in the rod from 10lbs not underwater?

i know the fish fighting adds to the formula, but i am always left guessing. thanks

Yeah, buoyancy and all that. Most fish are pretty close to neutral buoyancy in water so they "weigh" not very much and most of the pull comes from either drag in the water or the fish pulling on your line.

There aren't many fish that can pull against their own weight of drag - a fired up Yellowtail might manage to do it once or twice.

A 10-lb lead weight weighs approximately 9.1 lbs in salt water due to the upward buoyant force of the displaced water.

A 10 lb fish weighs approximately 10 pounds in saltwater, as fish are generally neutrally buoyant and their weight remains the same as the weight of the water they displace. The idea of weight in water typically applies to objects with significantly higher density than water, like rocks or metal, which would experience a reduction in their apparent weight due to the buoyant force of the water.

If a fish has a mass the same as the volume of water it displaces, then it will have a "weight" of zero (or more specifically, the upward and downward forces will be balanced). Otherwise they would all sink to the bottom or float to the top 

Great question Hank. Wondered about this too. When grouper fishing, I use a good spring scale to set my drag to 17lbs, approximate weight of a 32" grouper. Several times I've had a 27"-29" grouper, 10-12 lbs respectively, pull quite a bit of line against the drag.

The load that you feel is the mass of the fish (less the buoyancy factor) plus the friction from pulling the fish  and line through the water plus the amount of propulsion the fish is applying, plus the effect of current on the fish, plus the effect of current, wind and propulsion on the boat (if you are not land based)and probably some other stuff that I forgot.

And don't forget the rod length and fighting angle. With the line at a 90 degree angle from the rod butt, you could easily be pulling six or seven times the load that you would feel if you were pointing the rod straight at the fish. This won't affect the load on the drag, but will affect how hard you have to work to hold onto  the rod so that the drag can do its job.

-J

The rod would feel the same as in your test if you tried to hoist a 10 b snapper over the rail instead of using a gaff or hand-lining it up.

One time I tried to check the drag and the guides didn't like the braid ?

  Just a friendly reminder 10. pounds at full spool is not the same at 3/4 or 1/2 spool it is more