# Diving depth? Vodkaman help!

## 28 posts in this topic

Why are diving depths listed for trolling so much greater than depths listed for casting? As an example they show a Rapla dt-10 hitting 12-14' with 20' of line out but yet on a 100' cast they only show it hitting 10' with compareable line size? Just trying to understand the mechanics of what Im looking at. Thanks

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That does not read right. Surely with more line out, the thing should swim deeper.

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Sorry the 20' of line out is meant to say trolling with 20' of line out, however I read the book wrong and it was at 40' where it exceeded casting depth of 10'....I guess what Im not understanding is we move the bait with the reel from a stationary boat, trolling, the boat is moving but not the reel... is the difference in depth due to boat speed or line out? I was always of the understanding that a bait will only hit a certain depth no matter of the speed of retrieve, sorry for the confusing post Im not really sure how to word this question? So in a nutshell their saying that trolling the same lure with 40' of line out acheives a greater depth with the same bait than casting the bait 100'

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VMAXX - The drag on the line @ 100' is four times the drag @ 50' (I think) so this drag and accompanying bow in the line, lifts the lure higher in the water. pete

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I just read a comprehensive article on the subject. It basically says that most lures reach 90% of its max diving depth with 120ft of line out. It also states that each lure is an individual entity and that some lures are only just getting warmed up with 120ft and will perform with far more line out.

http://www.precisionangling.com/learn.html

So, I find your figures strange. Perhaps you could post a link to the table that you are using.

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Seems to be dead Dave, I have cut, copied, pasted, shortened, Googled, and no go, I will certainly have to have a look when it is back up. If you Google it there is a heap of links. pete

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Yes, that is the doc I read. Here is a paragraph from it:

"Every crankbait is an individual that has its own distinctive diving curve," says Holt. "Some lures reach their maximum diving depth with 120 foot leads, but many lures, especially deep divers are just getting warmed up at 120 feet."

I'll try to find a table later, but it all sounds wrong to me. More line should give more depth, up to a limit.

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I believe that is the same place I'm getting my info, a friend at work has the trolling book while I have the casting. I know I'm probably confusing the hell out of you guy's:(sorry, maybe I can clear up my question...in the books a casted crankbait does not get the same depth as a trolled bait(same bait), in the casting book they show a dive curve where a bait reaches it's maximum depth, runs at that depth without getting any deeper for maybe 10-15' and then starts the curve up to the boat, while a trolled bait with less line out than what the casted bait uses dives considerbly deeper(info from the same authors) At the moment I don't have a way to copy the charts or I would. What I'm not understanding is why a bait (casted) to 100' doesnt dive as deep as the same bait trolled with 40' of line out? What forces a trolled bait to run deeper?

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Aaaahh, now I get it.

Even though the trolled line may be shorter, it is trolled a lot further and has more time for the line to settle down to its balanced condition. The water pressure on the line causes it to belly in an arc. The angle of the line at the end of the arc is what determines at what angle the lure swims at. The line to lure angle is a constant. If the line angle is shallow, the lure swims down. As the line settles, the angle shallows and the lure will dive down a little more, until it all balances out.

I didn't really explain that very well. If you are as confused as I am, let me know and I'll have a think and try again.

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It seems to me that a trolled lure might take a minute or two to get to that depth and stay there because the line is still 50' out. A cast lure, when retrieved from 100' probably does not reach it's max depth by the time the line gets to 50' (depending on dive angle and the extra line drag)- by the time it reaches 50' the lure to rod tip angle is increasing , so you are starting to pull UP against the resisting lip(lure), at an ever increasing angle (to the water surface). Have you ever noticed when retrieving a lure to a boat, that the lure will go past the rod tip and under the boat, before turning and coming out of the water. The lures I am currently making will consistently hit bottom (15' to my suprise) at about 150' trolled, but casting them off the shore (nowhere near 150' unfortunately) I can retrieve it nearly to the bank where it would bottom out @ 4' where the rod tip to lure angle, would be about 90 deg.The lure maintains it's dive angle but because the tip to lure angle gets steeper, it is allways rising.

Clear as mud?? Dave will give you the numbers. Best I can do. pete

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Even though the trolled line may be shorter, it is trolled a lot further and has more time for the line to settle down to its balanced condition. The water pressure on the line causes it to belly in an arc. The angle of the line at the end of the arc is what determines at what angle the lure swims at. The line to lure angle is a constant. If the line angle is shallow, the lure swims down. As the line settles, the angle shallows and the lure will dive down a little more, until it all balances out.

Well, that was about as clear as mud!

Pete, I think you have got a good handle on it. I'm not sure about the last paragraph. Are you saying that you don't think the lure got deeper than 4ft?

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Vman, you convinced me, so I agree.

A small mention, though.

I think the depth at which the trolling crankbait reaches a balance also depends on the speed of the boat. But I cannot imagine how the speed does that.

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Dave - I was getting a bit out of my 'depth' there. I was trying to say the shorter the line, the greater the angle between the rod tip and lure, so the shallower it will go - I think. pete

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Don't mean to steal a thread, but its about swimming action. Is it better to put ballast weight near the front or the center of the lure if you want to maximize action?

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Pete and Dave thanks for the insight! Now to let it sink in! It was just something I had stuck in my head and couldnt think it thru.

Stacey

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Kribman. It is best to have the ballast as close as possible to the CoG, you may want it slightly forward, to control the floating angle.

When you add the ballast, you affect the CoG. If don't place it at the lures CoG, then the new CoG will be offset from the ballast and the original CoG and the action will be reduced, due to inertia of the ballast and the body. The denser the body material, the worse the problem. Balsa is so light, which means more ballast required. So, where ever you put the ballast is where the new CoG will be and the centre of the 'X'ng action or wiggle.

So the answer to your question is: the centre.

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To go back to the main topic of this thread for a second... The way I always understood it was the longer the lure is allowed to stay in the water the deeper it will run; of course until it tops out at it's maximum depth. So if a lure is cast 100' and you retrieve it -depending on how fast you retrieve it- it could be in the water anywhere from... oh, say 20 seconds to 60 seconds (just threw out some numbers).... But if you're trolling a lure it can stay in the water for as long as you troll for, thus letting it reach it's maximum depth. Also, because the lure isn't being retrieved back to the rod it can stay at it's maximum depth. That's just how I always understood it.... Sound about right?

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That is correct. But the lure does not have a maximum depth. Given the right tow line angle, it will keep diving. All the limitations to diving are in the line.

If you use the thinnest line available, the lure will dive deeper, quicker. The thinnest line has the least resistance to the water and will 'cut' through the water easier.

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There's gotta be a maximum somewhere Dave.

Hehehe, but I do understand what you're saying.

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Yes, but is all about the line.

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I think Vodkaman has it. If you cast a crankbait 100' it has a dive profile to max depth but soon after starts rising back to the boat. Most crankbaits stay at max depth for only 15-20 ft. When you troll the same bait, it has the same initial dive profile. But after reaching max depth, it doesn't get upward force applied to. In fact, the line angle that caused it to dive can keep getting more acute as you pay out more line. The bait keeps working deeper until upward line drag, bait bouyancy and lip resistance reach equilibrium. Lots of baits that cast to 15-18 ft will troll 30 or 35 ft if you let 150-250 ft of line out and you're using thin braided line or wire.

Exactly.

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Ok thats where Im getting lost,if you read these books on their dive curve (casting) they dont show a bait hitting a peak and then starting the incline back to the surface they actually show it bottoming out(so to speak) once it hits it's maximum depth and running their for maybe 10-15'...then starting the curve to the surface. If we go by whats said shouldnt the dive curve continue downward reach the point where the line angle overcomes it and it returns to the surface? So if I cast a bait,then free spool while backing the boat up with the trolling motor and lay out say 150' of line I can get a deeper dive? Sorry:eek: I'm just trying to clear my head!

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This is what happens when I read too much,but it is wintertime

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