The graph is good for all weights of lead core. The thing that you have to know is the sinking rate of the particular lead core that you are using. From data in the Precision Trolling book, using 18lb the sinking rate was measured to be almost 7 ft/color to about 6 colors and about 4ft/color after that, for an average of about 6ft/color for a full core.

The graph is only good for lead core. Dipsey divers are cover extensively in the Precision Trolling Big Water Edition. They have various sizes with and without O rings and different settings on the weight, lots of info. I've use dipsey on Lake O and they work good. Guys will give info as to line out and setting of the fish bite on dipsey. I've also used lb ball down the shut with good results, there is curves in the book covering lb ball.

I disagree with the numbers in the graph, in fact i think it is way off, but hey what do i know i didn't write the book.

the only way to get those depth numbers would have to be with really long leaders and a small but very heavy lure.

Several weeks ago on the Glander
Forum discussing lead core, “syonker”, provided some specifications of depth for lead core from the book Precision Trolling for speeds of 2 and 3 mph. I thought that knowing one point, speed versus depth, one could predict other depths for other speeds, by using the scientific principle of; force on an object varies as the square of the speed of the media, in this case water. So, the force on the lead core line that is in the water is affected by the speed of the boat, if the boat speeds up the lead core will come up and converse when the boat slows down, the lead core will fall deeper.

The graph represents the principle in ratio form for predicting speed effects on lead core due to speed changes. The reference point of 2 mph was used because a depth data point per Precision Trolling was known, measured.

I do understand that speed effects the depth obviously.
A lot more than just speed affects it too, but i don't agree with their reference point depths at 2 mph even.

5 colors of lead at 2 mph will not be 30 feet down unless something is added like a deep diving rapala or hunk of lead or maybe a cod jig.

But Hey maybe i am crazy, anyone else have an opinion on this one, grey ghost you must have an opinion if the #'s are right or wrong? How close do you think they are.

I believe 6 colors will get you 28 feet and a full core will get about 40 with 18lb. I don't have hard facts to back it up but it is what i think. at 2 mph.

Main reason i believe this is the morning fish now are at 34 feet pretty steady and i can't touch one with lead unless i am out 7-8 colors with their chart i would get bites with 5-6 and i don't.

I too doubt the "depth curves" published for leadcore. The only time I think I've approach the 5-6 ft / color is when I've used a keel weight / sinker in between the leadcore and leader. That seemed to work pretty well when I tried it at Moosehead last year. I think Cabela's and others are trying to make us feel we can do with leadcore (cheaper) than what you can do with a 'rigger...but you can't.

I'm going to try even heavier keel weights (5/8 to 1 1/4 ounce) and see if I can get more predictable sink rates....good discussion on this as always

The Precision Trolling Big Water Edition was put together scientifically, that is to say under control condition. Data was taken on calm water days at a known speed and a diver down to make the observation and record the data. Read the bio’s of the authors. Is there any data out in the fishing world that contradict the data that was collected?

We in the fishing world only provide anecdotal observations, biased with what ever biases that we have been exposed to in our fishing lives.

I don’t believe that any lead core manufactures have done any testing under control conditions. I just received information from Cortland and requested sinking rates for their lead core, they sent me ever thing else except sinking rates. I'll have to ask them directly if they have and performance data.

Ok, That being said Grey Ghost what are your anecdotal observations based on your own fishing experiances about how fast lead core sinks?

I will be putting together an article that discusses what we have talked about so far and additional information on lead core in a concise format. When driving up to the lake Friday to fish with Salty, I thought about several other points that are relevant and should be discussed to portray a clearer picture of what is happening when fishing with lead core. This whole process, is a learning experience for me to delve into the nuts and bolts of lead core trolling as to why thing are the way they are. It will take me some time to get the data and present it in a manner that all can understand.

Thanks to all who shared information on my question. It is great to have a site where everyone shares information so freely. Thanks again

I by no mean's know 1/2 as much as some of the pro's on here but i do know that i bought a new leadcore set-up from A.J.'s i wish it had the line counter on it but unfortunately it doesn't. When i went up to Canada a few weeks ago My leadcore outfished both the downriggers and my buddy's leadcore set-up (not sure why as he also has 18# lead with approx the same amount of leader) my pole counted for approx 80% of our catch's, but i was also 9-10 colors out with about 75' of 10# fluro, and an 8' leader of 8#fluro attached to it, the other leadcore was catching fish too but also with 9-10 colors out. When i fished the Winni Derby i caught my only nice Salmon out 10 colors down by Rattlesnake and Aardvark estimated i was down about 40Feet, I usually use only Dbsmelt lures and top guns only once in awhile do i put on a bigger spoon such as a big sutton when i'm trying to catch a Huge Laker LOL Only my 2 cents as like i said i don't know 1/2 as much as guys like Adrian and Travis LOL Take Care God Bless and Tight Lines LOL Dave From up North

It is strange how sometimes the lead core will consistantly outfish the riggers and we know how deep riggers are, lead core is only at best, a good guess.

Travis allways told me if you catch bottom you then know how far down you lead is/was, LOL how trues it is.

When I read about sink rate are we talking about how fast it will sink or how deep ????????? Not really that important to me just thought I would throw it out.

You guys lost me days ago with the first paragraph, especially Gus (Gray Ghost) and Adrien, WOW you guys are talking a whole new launguage for me, LOL.

John S.

Just a thought on leadcore. With that many colors out.And with a windy day. Would this affect the action on lures. With the wind affecting boat speed also waves.I know underwater currents do. Maybe its the windy days. When leadcore works better. Nothing to back this up. Just thought of this while reading the other replies.