Round Lip Vs Square Lip
35 replies to this topic
Posted 10 August 2011 - 05:26 AM
I had already constructed two identical prototypes for another project, one with a square lip, the other round. Both lips have the same maximum width, length and root width. I thought it would be interesting to video a comparison between the two.
The action of both lures was pretty much the same. The round lipped lure definitely wanted to swim deeper than the square lipped lure.
I found it interesting how both lures always swam in sync or 180 degrees out of sync, except when they got too close to each other. Even though both lures are hitting 'clean' water, the water disturbances act as a system, so even though the lures appear to be independent of each other, they are not.
there are plenty of reasons for using different shaped lips, action, it seems, is not one of them.
Posted 10 August 2011 - 11:01 AM
And now accepting the award for best video in an above/under water setting, Dave "Vodkaman"!
Great video! Those years of making adult movies sure did pay off!
I've found that my square bill lures swim a little more shallow, because I make the bills only slightly wider than the lure body, while I make my round bills much wider than the lure body.
I find that the shape of the lure, round vs. flat sided, is what determines how much wiggle and wobble my lures have.
I made a flat sided deep diver with a bill the same length, 2", as a favorite round bill that runs to 16'. But my lure's bill was only slightly wider than the lure, 7/8" instead of 1 3/8", and it only runs 12-14' on 10lb test.
Posted 10 August 2011 - 02:25 PM
Like the video work. Love the test tank.
The round bill looks a bit smoother to me.
Have you tried a coffin bill?
Posted 10 August 2011 - 02:59 PM
Mark - The making of this video was just as difficult as those old adult videos (how did you know?). Spectators are always a problem, wanting to get in on the action. Trying to come up with a new camera angle to capture the detailed action is always a challenge. The subjects never seem to wiggle exactly how you want, never follow direction commands and were always getting tangled up. Deep diving is always a problem, but as long as you use rubbers on the pointy bits, no damage is done.
Littleriver – I have not tried a coffin bill. I would not expect much difference, as a coffin is basically half way between the round and square bills. Seeing as depth actually registers in my shallow tank, I thought I might compare square and sharp lip edges next. We know that sharp edges have more action and dive deeper, at least in theory, but how significant is the difference?
Glad you all liked the vid.
Posted 10 August 2011 - 04:47 PM
I speculate that the round lip dives more because it has more surface area closer to the end of the lip (say first third or half) thereby catching more water lower on the bill. This then results in slightly more of an angle on the bait forcing it deeper. I can't confirm this without a side camera angle of the action!
I wonder if this occurance is primarily noted with casting only, or does this hold true for trolling as well.
Posted 10 August 2011 - 06:49 PM
Here is a couple links to articles on this subject.
They are insightful.
I only mention coffin bill because I recently made two lures nearly identical except two things bill and paint.
One was round and the other coffin. To my surprise the coffin ran smoother with very nice tight wiggle.
The kids painted their own bait and chose the bill design. Bodies, weight and hooks were same.
It was my first coffin bill. I will be making more.
Posted 11 August 2011 - 12:19 AM
I read the article provided at the links above and they said the reason you didn't see deeper diving baits with square bills is that they didn't work. What about Mudbugs? They have square lips although with a scalloped leading edge on the lip. And some of the lips on the deeper diving 'bugs are quite large. Is it the scalloped leading edge on the lip that allow them to work or was the statement in the article made in error?
Posted 11 August 2011 - 12:54 AM
Not really sure about the mudbug. How deep do they go? I have tried making some deep diving square bills without success.
Then I found this so i stopped trying. My lure is similar to a mudbug but the size and length and angle and tie position of bill would not make go deeper than four feet. The mud bug has a narrower and thinner bill than mine. This may help it get deeper. With the bill in the horizontal position and location of line tie the mudbug is designed to go deep. How deep? I would love to get my lure to 10 feet.
Posted 11 August 2011 - 02:59 AM
As always. interesting stuff. Thanks for sharing.
Posted 11 August 2011 - 04:29 AM
Vic – very interesting articles, thanks for posting. They should generate some discussion.
The reason I shot the video of the two lures together, is that after I shot video of them separately, I could not see any difference. The problem was watching one video, remembering the action, then flipping to the second video for a comparison. The differences were so slight that I could not tell. My editing software is not sophisticated enough to allow me to superimpose videos unfortunately. I can post the individual videos, if you would like to see them.
But, now having video of the two baits side by side, I still cannot see any differences. After reading your post, I went back and watched the video several more times, nada. I do however feel that the two baits are affecting each others action, as I stated earlier. With such a significant difference in lip profile, I did expect to see at least a slight difference.
Even before reading your article, I was considering a ‘rock test’, to test out the bouncing attributes of each lip, I actually posted this intention on another forum. But I feel that the short tow line that I am limited to, is not going to give realistic results. Still, may be worth trying, as this ‘bouncing off cover’ thing has been discussed here on TU many times in the past.
You have aroused my interest in at least building one coffin, to add to the comparison. If you could give me some dimensions or a photograph looking straight on to the lip, I can reproduce it to the size I need for the direct comparison.
Sbaits – interesting point. The round lip definitely does seem to have a larger surface area in the lower half of the lip. So I fired up the CAD, measured the exposed lip length and trimmed the CAD model back to suit. Threw a ‘fill’ surface on the profiles and measured the areas: the round lip area = 3.481cm², the square lip area = 3.626 cm², so actually, the square lip has a larger area by about 4%, so not much difference, but not the expected result.
My theory is that it is more to do with the lip edge length than area.
Posted 11 August 2011 - 10:44 AM
I am guessing you already did the frame by frame or slow motion replay.
In some of the shots it looked like the top to bottom wiggle was different, while the front to back wiggle was the same. In other shots I didn't see it. Over all I have to agree there isn't much difference in the action of the baits.
Posted 11 August 2011 - 12:14 PM
Regarding surface area not being the expected result. To clarify, both lips total surface area are equal and the front half of the square bill has slightly more (% wise) than the rounded lip. If so that is unexpected and now I'm buying into the front bill length as the deciding factor.
I brought up trolling vs casting for a reason as I'm curious if this will only result in one bait getting down faster but not actually affecting max depth.
As for square bills not being for deep divers, the believer is a built in square bill and it dives about 20' deep and is extremely buoyant so I don't think one can rule square bills out for deep divers.
Posted 11 August 2011 - 03:15 PM
Dave, great effort there.However, you can't see very well on bare lures the wobble and roll the lures have and quantify them.
Suggestions for ur future comparison videos or even for single lure.
1. Draw a nice clear black centre-line on the top of the lure. This will give a better indication of the magnitude of wobble and I bet you would stop frame and measure the deflection too ; the centre-line view from top will also indicate how much the lure rolls.
2. Side view can do with a centre-line and a vertical line in a different color. Your wheels turning already about what these lines will tell you?
Edited by LaPala, 11 August 2011 - 03:17 PM.
Posted 11 August 2011 - 07:26 PM
It is good to think.
Here is photo of the the two lures. The coffin is the first and only one I have made but I liked how it swam. Very smooth wiggle. Very fish like. You can truly make one any way you like. This one was done hastily but effective. The coffin I made is appx. 10mm widw at tip, 15mm wide at base, short sides are 15mm in length, the long sides are 25mm in length. Total bill length is 40mm appx. and 25 mm at widest point. Center of tie point is 25mm from leading edge of bill.
P8114593.JPG 170.01KB 55 downloads
Posted 11 August 2011 - 07:55 PM
Vic - thanks, exactly what I needed. I'll build one today, to add to the test.
LP - Thanks for your input. You are right, I should have been doing the line thing all along. I have done it to a few proto's, but then got lazy. I will add some lines and see if it shows up any differences.
Posted 11 August 2011 - 08:55 PM
Interested in your line of thought, I did a bit more investicating and measured a few different areas, the pic below is the result of my findings. This is not about proving you right or wrong, in fact I would have thought the results would have been as you presumed, but not so.
Posted 12 August 2011 - 02:31 AM
I was wondering can you feel any difference? Say when the lures are pulled thru the tank separately. One at a time. The article talks about one
hitting harder on the turns than the other creating more vibration. I can feel a difference between the round and coffin bills. Might be hard to see
but easy to feel on the end of a rod. This difference is more pronounced the faster it is retrieved.