Rick:
Pursuant our conversation last night and with specific reference to your question as to whether a sinking line sinks at a faster or slower rate as water temperature decreases, I have done some research.
I took two tall glasses; filled one with water at 200degrees F., and the other with water at 34 degrees F.
In each, I dropped equal 1" segments of the same class IV fly lines.
Then I did the same thing with equal 1" segments of an Intermediate fly line.
The class IV segments each settled so fast that I, frankly, couldn't tell if there was any difference in the sink rates.
I got the impression, after doing this many times, that the Intermediate segments were very slightly different, the ones sunk in the 200 degree water having a sink rate very slightly greater (faster) than the ones in cold water. THE DIFFERENCE WAS SO SLIGHT, HOWEVER, THAT IT WAS HARD TO BE SURE OF THIS.
I, then, accessed some information from the U.S. Hydrographic Office as well as an article from the physics literature: THERMODYNAMICS: AN ENGINEERING APPROACH..... by Yunas A Cengal, (U. of Utah) and Michael Boles, (North Carolina State U.). Information gained was as folows:-
1.) Gravitational acceleration is 9.807 m/s squared at sea level. It varies by LESS THAN 1% DOWN TO 30,000 meters. SO...this can be assumed to remain a constant at 9.81 meters per second. This means that: THE SINK RATE OF OUR FLY LINE DOES NOT CHANGE PERCEPTABLY WITH CHANGES IN ITS DEPTH.
2.) Liquids (including water) are incompressible, so have densities that have negligible variation with pressure. (Density defined as mass per unit volume.) Translation: CHANGES IN PRESSURE (SUCH AS ATMOSPHERIC PRESSURE) YIELD NO CHANGE IN WATER DENSITY, THEREFORE PRODUCE NO CHANGE IN THE SINK RATE OF THIS FLY LINE.
(I mentioned the above, because salt water fishermen are keenly aware that changes in atmospheric pressure have a significant effect on tidal flows and water depth in tidal areas. as well as the distinct impression that game fish respond to changes in atmospheric pressure )
3.) Fresh water at 4 degrees C has a density of 1000 Kg/ sq. Meter. This density DECREASES as water temperature increases. One "anomalie", is that the reverse is true beween 0 C and 4 C, where the water density actually increases as we go from 0 degrees C to 4 degrees C !!!!!
The measurements were: Density of freshwater increased from 999.85 Kg/M squared at 0 degrees C to 999.98 Kg/M squared at 0.4 degrees C.......THEN DECREASED TO 999.50 Kg / M SQUARED AT 12.0 DEGREES C !
4.) Now, the sink rate of an object in fresh water is proportional to the difference in density between that of the object and that of the water. Or: A MORE DENSE OBJECT (SUCH AS A SINKING FLY LINE) WILL SINK FASTER IF IT MORE DENSE.
5.) Since the density of water of 4 degrees C decreases as the water temperature increases, and the converse is also true (the density of the water increases as the water temperature decreases....down to 4 degrees C), and since objects sink faster in water less dense and more slowly in denser water, it holds that: IN WATER BELOW 4 DEGREES C, OUR SINKING FLY LINE WILL SINK MORE SLOWLY IN COLDER WATER AND MORE QUICKLY IN WARMER WATER. (A PARADOX IS THAT THE REVERSE IS TRUE IN WATER BETWEEN 0 DEGREES C AND 4 DEGREES C.)
CONCLUSIONS I. Having said all this, the figures indicate that for practical purposes, these differences are so slight as to escape our actually being able to detect them.....so are of theoretical value, only.
II. What Bruce Richards told you is correct !
Advice to Masters candidates: Do NOT give a long answer like this on your exam ! Keep it short and simple.
Gordy