[BobP]

The most direct method I know to get a suspending wooden bait is a float test. Completely finish the bait but without any ballast. Attach the treble hooks. Float the bait in water that is the same temp you will fish in. Hang lead on the trebles until you get a slow rise, then use the lead for the ballast and patch the holes. If you fish it in water that's warmer than the test water, it will sink. In water colder, it will rise. It's best to build for a very slow rise which can be corrected by adding some Suspend Strips or lead wire on the trebles. The next bait you build in the same pattern will be close if you use the same batch of wood and the same build details.

[mark poulson]

Boats float because they weigh less than the water they displace. Steel or wood, it's the same idea.
Probably a good way to measure how much weight of water your lure displaces is to float it in a graduated glass jar, and mark the water level when it's floating. Then push it down until it's just barely covered by the water and mark that level.
Weigh the amount of water that the level rose, and it will tell you how much your lure needs to weigh to achieve neutral buoyancy and "suspend". I put that in quotes because, in reality, the chances of truly suspending are minute. If you put a suspending jerkbait in a pool, and pull it down to 4', it will eventually fall or rise. And it will act differently at different times of the day, depending on both water temperature and barometric pressure.
And a slowly sinking lure that's retrieved faster will stay up near or at the surface.
Another factor in suspending is line. A lure that sinks with 8lb fluorocarbon line will rise with 20lb monofilament.
And a truly neutrally buoyant lure, for me, is only really important in the winter, when the bass take a while to come up close enough to the lure that they'll hit it out of reaction on the next twitch. Even then, as long as the lure gets down to their level, and then either rises or falls slowly, they'll come up and check it out. They can't help it, they're curious creatures.
If you want a perfectly suspending lure, like David said, take some suspend dots or strips to the lake with you, and fiddle around all day. Not only will you lose fishing time, you run the risk of ruining, or, at best, altering the action of that lure.
So, in conclusion class (I've always wanted to say that ), in practice, a lure that's close is all you can hope for, and all you really ever need.

[hazmail]

Maybe it would be simpler to make them sinking with an air bladder built in!! (just like the fish do). Some of those lures you guys build would accommodate a 'small' condom. I am just visualizing guys on the bank with thermometers, blowing up their lures for the day (Nitrogen would be better).
Remember the submarines we had when kids, that took a puck of bicarb soda which made CO2 gas, up she came and down she went. A small air bag and a syringe, may be the solution (until the water heated up). A lot of this is in jest, but this is another angle that fish use for neutral buoyancy, and you can not beat mother nature for ingenuity. This, I feel has at the very least, got Dave thinking, (he has probably already tried it). Love this brainstorming stuff, and all these practical solutions offered. pete

[LaPala]

Pete, there was a lure that does the exact opposite. It's floating and u inject water thru a rubber nipple to get it to slow float or suspend. Forgot what brand but it's pretty old. Maybe someone still remembers it.

[Palmetto Balsa]

Norman Baits made it. It was a Jerkbait style lure and had a syringe in the package. Add water then you would just plug the hole with a stopper.

[KcDano]

How about the worm blower, plastic bottle with a hollow needle to inject air in worm to make it float

[carpholeo]

Thanks for all the extremely informative,lengthy and confusing replies to my question. With all the tutorials,theories and excellent advise from this thread, I now feel that I can dive right into my next suspending bait project with the utmost confidence and enthusiasm, and then fail miserably.
But seriously, I will take into account all that I've read here and document my progress as I fumble through it.

A few things I have to my advantage is that I have already made the lure I want to recreate and being A catfish replica, it has lots of accessories attached to it that could be weight adjusted for balance. And the real biggie it that I'll be using it in shallow water that the temp doesn't vary all that much.

Thanks again everyone

[captsully18]

This may do nothing more than cloud the waters even more, but...... I usedto SCUBA dive a lot, and would use my flotation vest to overcome the weight of the belt in order to achieve neutral bouancy. This was great for reef diving or wreck diving. The whole time underwater I had to keep adjusting the air in vest as I would be either too light or too heavy at any given time. In actuallity I was never completely neutrally bouant, just on the very edge a lot of the time, then had to adjust. I do believe that NEUTRAL bouancy is a thing that can be achieved in one place, one time and that is it. Take same perameters to another place/time and you are only close. Lots of variables involved (depth, temp., water movement, etc.). If you can come close in your tests you have done a great job indeed. Just my .02.

David

[LaPala]

Errrr David, I need to butt in here , no offense intended about ur diving.

The whole time underwater I had to keep adjusting the air in vest as I would be either too light or too heavy at any given time.

What is happening is you might be diving over-weighted. When over-weighted, you have to put a lot more air into your buoyancy compensator to achieve neutral buoyancy. More air in BC = more change in air volume for every change of depth that needs you to correct the amount of air to achieve neutral buoyancy. And in this case you need to adjust a bigger volume of air too. By trimming the weight you wear to just enough (fine tune with shot weight belt instead of the chunks) you could negate the need to constantly fiddle with adjusting the air in your BC when you stay at a relatively constant depth; because the air needed to trim for neutral buoyancy will be less; less air in BC = less air volume change = less adjustment needed. The other cause would be yo-yo diving where you constantly change depth up or down. So if none of the 2 scenario is involved, you do not really need to adjust your neutral buoyancy at "any given time" it is only needed when depth change is significant enough to affect buoyancy. Buoyancy change is also relatively less and less significant as you go deeper (Boyle's Law) Sorry for the discourse here guys.

Anyway applying the same to lures, we have so little volume of air in a lure (especially a wooden lure) the change in pressure that compresses the air and causes reduced buoyancy is close to negligible at depth. (even less if the lure attains deeper depth. Opposite happens if a lure is floating up, reduction of pressure allows air to expand, buoyancy increase.). As we would be designing a suspending lure to suspend at a fixed depth that the lure is designed to dive to, the air compression buoyancy factor can be safely ignored. Line diameter, line weight does affect how deep the lure will dive to. Temp effect on buoyancy do have to be considered. A suspending lure in winter does not suspend in summer .

So ideally all suspending lure should come with a note that says, "This lure suspends at X depth, with Y water temp and designed depth of lure is achieved with Z diameter AA type line with an average cast of XX feet." I think that about covers most of the suspending issues .

[jim45498]

I put my hardware on the bait, then tie a string to belly hook and add weight to string. I push the crankbait under water by hand (a couple feet deep). When I get the slow rise that I am looking for, I put this weight in the belly.