Super User OkobojiEagle Posted February 19, 2013 Super User Posted February 19, 2013 Known... as water warms it becomes less dense, causing baits that suspended at the cooler temp to sink at the warmer temp. Also known... water pressure increases with depth. Can it be calculated at what increased depth a bait will suspend as the water density is increased with depth? Another variable...at deeper water depths in lakes, the water temp is most often colder. Can the suspending depth of a bait be reliably calculated based upon the water temp at given depth intervals? oe Quote
Super User SPEEDBEAD. Posted February 19, 2013 Super User Posted February 19, 2013 I think the difficulty in keeping that bait in the "prime" zone for suspension would be huge, especially if we are talking cast and retrieve lures. The curved ends of a cast with the bait getting to maximum depth and then you reeling back to the boat keep it "deep" for a relatively short time. Long line trolling a lure may yield more effective results. Just thinking out loud with you. Quote
lmoore Posted February 19, 2013 Posted February 19, 2013 Water pressure at depth would be irrelevant since it would be acting uniformly over the entire surface of the lure. For calculating depth of suspension, you would need to know the density of the lure and compare to the density of the water at a given depth, which is almost entirely affected by temperature (assuming pure H20). Plotting the comparison of density and temperature gives you the approximate formula D=-00.14T^2+.0897T+998.65 D+Density(kg/m^3) and T=Temperature (F) Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 Essentially, you are correct this is a function of density. To achieve neutral buoyance (i.e.the condition which causing a suspending bait to suspend), the density of the surrounding water (in a volume equal to that of the bait) must be equal to the density of the bait. Recall (from physics) that: Density = m/V (mass divided by volume) Figuring the mass of of the bait should be easy (just weigh it in grams and convert to kilograms, SI units work much better for these calculations so get water temps in Celsius). Not sure how to accurately measure volume of the bait except to submerge in a graduated cylinder in a fluid of known density, The volume of fluid it displaces (read on the cylinder) is equivalent to the volume of the bait. Not just divide your mass in kg by the volume in Liters and you have the density of the bait. Online, you should be able to find a table of water density versus temperature (most thermodynamics textbooks have them too). Measure the temperature at the depth you would like to fish, find the density of water using the table, then select the exact density bait. A long answer to a short question, but you got my engineer's brain thinking and thought experiments like this are always fun to do. ....I am a little bit weird, comes with territory of engineer.... 3 Quote
Super User SPEEDBEAD. Posted February 19, 2013 Super User Posted February 19, 2013 What's winter? It's when your bass spawn. LOL 1 Quote
BasskingKeith Posted February 19, 2013 Posted February 19, 2013 lol I'm kidding. That's an interesting topic, though. The only thing I can think of is how deep do you plan on getting a suspending lure on one cast in order for it to start sinking or floating?. Will it start floating more due to the pressure? Or sink better? Quote
Super User Teal Posted February 19, 2013 Super User Posted February 19, 2013 Dang, i think thats the episode of Mr.Wizard that I missed. Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 Pressure on the bait doesn't play into as much as density. Since pressure is a function of density the exact water pressure on the bait will not affect buoancy. The pressure at a given depth acts equally on the bait in all directions (in a static sense, after the bait has sunk and before retrieve). 2 Quote
Super User roadwarrior Posted February 19, 2013 Super User Posted February 19, 2013 You guys are giving me a headache! Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 Roadwarrior, After engineering school this is how I think about everything...it's what they drill into our heads. Sometimes I think the inside of my head would be a very scary place to reside... Quote
lmoore Posted February 19, 2013 Posted February 19, 2013 It's unfortunate you went to such a terrible school of engineering. Quote
Super User roadwarrior Posted February 19, 2013 Super User Posted February 19, 2013 My son-in-law is a Civil Engineer, currently working on an interstate project. Much of his work involves water issues, but some of it is railroad bed composition. I am not always sure what language he speaks. Did your school compete in the Concrete Boat Program? That was a lot of work, but it must have been fun, too. A few years ago the National Finals were in Knoxville, TN. The team from Seatlle spent a lot of time and money just to get to the event. An important aspect of the competition is that the canoe must float. Well, water density in Washington's colder environment is much different than here in Tennessee. The boat did not sink, but it didn't float either! I guess it turned into a Smithwick Rogue, suspending a few inches under water. 1 Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 It's unfortunate you went to such a terrible school of engineering ...Must be a Hawkeye... Go ISU Cyclones Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 My son-in-law is a Civil Engineer, currently working on an interstate project. Much of his work involves water issues, but some of it is railroad bed composition. I am not always sure what language he speaks. Did your school compete in the Concrete Boat Program? That was a lot of work, but it must have been fun, too. A few years ago the National Finals were in Knoxville, TN. The team from Seatlle spent a lot of time and money just to get to the event. An important aspect of the competition is that the canoe must float. Well, water density in Washington's colder environment is much different than here in Tennessee. The boat did not sink, but it didn't float either! I guess it turned into a Smithwick Rogue, suspending a few inches under water. We didn't have a concrete boat program that I was aware of. I spent my nights in the Aerospace building, but the concrete canoe competitions are cool. I spent my free time building rockets. Quote
lmoore Posted February 19, 2013 Posted February 19, 2013 I was a Civil Engineer also and we had the Concrete Boat team, but I was more worried about the ISU Fishing Club. That last one should help Mr. Richardson out. Quote
lmoore Posted February 19, 2013 Posted February 19, 2013 We didn't have a concrete boat program that I was aware of. I spent my nights in the Aerospace building, but the concrete canoe competitions are cool. I spent my free time building rockets. We had one, but it was entirely Civil and Construction Engineers as far as I know. Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 Now I got it. At least you are a cyclone and an alright guy to fish with. Now if only it wasn't civil engineering... I was a Civil Engineer also and we had the Concrete Boat team, but I was more worried about the ISU Fishing Club. That last one should help Mr. Richardson out. Quote
lmoore Posted February 19, 2013 Posted February 19, 2013 Now I got it. At least you are a cyclone and an alright guy to fish with. Now if only it wasn't civil engineering... We all have our issues. lol Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 We all have our issues. lol That's true Quote
Super User OkobojiEagle Posted February 19, 2013 Author Super User Posted February 19, 2013 LOL... now that all of you brainiacs have burned off your lunch carbohydrates... what I'm interested in knowing is... when I'm fishing a perfectly suspending Pointer 75 at 5' of depth over 30' of water and the sun warms the surface temp 2 degrees allowing that bait to sink... how much deeper will it sink before suspending again? oe (my son-in-law is an ISU grad... but he doesn't drive trains) Quote
Jmrichardson2011 Posted February 19, 2013 Posted February 19, 2013 LOL... now that all of you brainiacs have burned off your lunch carbohydrates... what I'm interested in knowing is... when I'm fishing a perfectly suspending Pointer 75 at 5' of depth over 30' of water and the sun warms the surface temp 2 degrees allowing that bait to sink... how much deeper will it sink before suspending again? oe (my son-in-law is an ISU grad... but he doesn't drive trains) That depends on a number of factors - How fast is the water heating up? how much has the 2 degree surface temp increased increased the temperature at 5' in the immediate vicinity surrounding your bait. It beomes a bit of a mess when dealing with transient heating (as the sun does not necessarily heat at an even rate all day). It involves partial differential equations and some magic to get the answer...if you are willing to compensate I am sure I could figure it out for you ...just kidding. It may be more fun just to set up an experiment to see how much the bait sinks as the water warms, I think some good electronics or a sonar flasher would be able to do the trick. Quote
RODNEY Posted February 20, 2013 Posted February 20, 2013 Hmmmmm, and I thought I was doing an intellectual thing deciding what colors to tie in my hair jigs. Rodney 1 Quote
lmoore Posted February 20, 2013 Posted February 20, 2013 oe (my son-in-law is an ISU grad... but he doesn't drive trains) Really confused me with this one for a minute since I actually do work for a Railroad. Lol Quote
Super User OkobojiEagle Posted February 20, 2013 Author Super User Posted February 20, 2013 lmoore... Quote
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