how deep is too deep?

[bigblue2]

I recently weighted some diver lure I made and water tested them in a 5 gallon pail the sink down fairly fast slightly resting on the bottom how deep do you think they will act when  thrown in a lake will they flutter down and rest  on bottom say 20 feet will they stop?

[bigblue2]

is there some kind of time measurement of sinking rate say a foot per second compared to weight of lure I suppose?

[Travis]

Simple answer is yes it will reach the bottom.  We can get into different variables and show how it will behave differently and find a condition,  outside the range of naturally possible, where it wont as in the water gets so cold it turns to slush.

Sinking rate will be dependent on several variables.  As the lure falls it displaces water and their is a force pushing up on the lure against that of gravity.  Water density (temperature), current, drag of the line, amount of line out, etc.. also come into play.  However once again the simple approach is just take your bucket example and determine the fall rate.  One foot per second, etc..

When I was a kid we used a lot of count down minnows to fish brush piles in the lake for bass.  You get surprisingly good at estimating depth and end up getting a feel for other lures based on how they "feel".  

[bigblue2]

so if the lure drops at say 1 ft per second that would be a good measurement to go by if the lure weight is less   it seems that it does not balance out  the body so I have to get a standard weight to go by so each lure acts the same or close to it?  

[bigblue2]

  I guess what I am really getting at can the correct weight balanced lure be so accurate to suspend at a given depth almost all the time?

[bigblue2]

want to hear a good one how about a automatic ballast system just set the perfect depth and the lure could maintain a given depth suspended?

[ravenlures]

Well eventuality in the ocean it will stop sinking. Getting a bait to suspend at a certain depth is not easy it drove me nuts, water temp. makes the difference, so I just get them to sink like I like them slow or faster.

Wayne

[Vodkaman]

My first thought was to calculate the density of your lure from the sink rate, conversely, to calculate the required density to achieve a specific sink rate. I figured that this information could be useful for lure designers. But alas, there is one significant unknown, the coefficient of drag of the lure. Another variable that would prove problematic is the area of the lure foot print. It would be much simpler to perform water tests – dangit!

However, other questions can be answered.

1 – The sink rate will be constant regardless of the depth and the increasing water pressure.

2 – The lure will not stop at a specific depth, given that the initial fall rate was 1ft/s.

3 – If the water pressure actually compresses the lure, which is actually a possibility, then the lure will sink faster.

The only way that a lure can suspend at a specific depth is due to the change in water temperature, which we know occurs. Temperature drops with depth. As the temperature drops, the density of the water increases. Because temperature varies from day to day, it is not possible to design a lure to suspend at a specific depth. The only solution is to adjust at the water’s edge on the day.

Regardless of the sink rate or float rate, the lure will swim at the same depth. I am not saying that weight does not affect the swim depth, but unless the lure is weighted to the extreme, then the water forces on the lure and the line will far outweigh the effects of gravity.

Dave

[mark poulson]

I've found that even the $25 Japanese jerkbaits, which are supposed to suspend, actually sink or rise slowly, depending on water temp, and line type and size, but not fast enough to matter.

I've also found it's impossible for me to get a lure to suspend perfectly, so I settle for close.  I get it to float really slowly, then paint it and top coat it, and hope the paint/top coat make it suspend in cold tap water in my float testing 5 gallon bucket.

Then I can use the type and size of line, and the size of both split rings and treble hooks, to get them to either sink slowly, or float slowly.

Worst case scenario, if the lure still floats once I'm finished making and rigging it, I'll add suspend dots/strips to the belly, or a little lead wire to the belly hook shank.

But I don't think the fish care if it sinks or rises, as long as it is a really slow movement.  Dying baitfish aren't neutrally buoyant, either.