DEPTH
by Chuck Bailey
I once attended a huge corporation party where mouth watering appetizers were being served on silver platters by waiters randomly going through the crowds. Problem is, none of them seem to come in my direction. All night long, where ever I was, the waiters weren’t. Seemed the distance between those mouth-watering delights and my empty stomach, prevented me from munching down.
Underwater, things work in much the same way. Generally a fish must wait until a bait comes close enough before a snack is enjoyed. Oh sure, occasionally a fish (when it’s in an aggressive mood) might be willing to travel a great distance to hunt a meal down, but most fresh water species spend most of their day conserving energy – in an inactive frame of being. That’s not to say that during those less active times they will not snack on a prey that wanders close enough - it’s just that the fish’s “strike zone” is smaller, requiring the bait to come to closer before the temptation or instinct to strike occurs.
The job of every angler is to reduce the distance between their target fish and their lure, (imitation prey). The angler’s ability to shorten the gap creates a feeding opportunity that tempts the fish to strike at it – therefore, making contact with the hooks that accompany the offering – in this case, a crankbait. I wish I could tell you that every fish nearby would take a swipe at your bait. After thousands of hours of looking through an underwater camera, I am convinced that many fisherman would quit the sport if they knew just how many fish watched their bait go by. Fact is, when an inactive fish has lock jaw, there is isn’t much going to persuade them to strike. Never-the-less, the closer you get a crankbait to the fish, the greater the chance that someone in the crowd will indulge.
That’s why depth is so important to an angler. Somewhere in the water column our finned targets swim; and discovering the depth they are hanging out in, helps us decrease the distance between the fish and our bait - and increase our chances of enticing them to strike. Of course, the angler’s ability to locate fish on any body of water is a whole science unto itself and will be covered elsewhere on this site. Right now, let’s focus on the factors that influence the running depth of a crankbait. It will help us fine-tune the task of reducing the distance between our favorite fish and the crankbait we are throwing.
THREE DEPTH RANGES:
Generally, (for bass fishermen at least), the water column can be divided into three depth ranges, requiring three categories of crankbaits:
1) 1-6 feet deep - Shallow divers
2) 6-12 feet deep - Medium divers
3) 12 feet and beyond - Deep divers
While trolling is not allowed in professional bass tournaments, weekend anglers can use the technique to get a crankbait down to extreme depths. Mann’s deep diver is said to run 75 feet deep on 150 feet of 17 pound lest line. Using down riggers with cannonball weights, (as salmon and walleye fishermen often do), can take a crankbait to any depth. (See ABC BASIC’s “TROLLING”) But when it comes to casting, an angler rarely gets a crankbait to dive below 20 feet - unless weights are added.
At this time, we’ll assume an angler already knows what depth they want to cover. Let’s focus now on how to “fine-tune” the running depth of our crankbaits in order to put them on a collision course with our finned targets.
THE FACTORS AFFECTING CRANKBAIT DEPTH:
THE BILL: If you have not already read the ABC BASICS article entitled “BILLS (LIPS)” you might want to do that first. The bill size and position are the primary influences affecting the path and depth a crankbait takes. Generally, the larger a bill, the deeper the bait runs. A bill coming straight out of the nose of a crankbait generally goes deeper that one angled downward from the body of the bait.
Fishing experience and engineering skills have led crankbait manufactures to put differently shaped and positioned bills on several styles of crankbait bodies so as to offer a line of lures that covers a variety of depths.
CAUTION: In my early years of fishing I often pondered why a crankbait’s depth was rarely written on the box. As time went on, I discovered “why” there was a hesitation or resistance by most manufacturers to declare a running depth. It’s due to the designer’s familiarity with the multitude of secondary factors that affect the running depth of a crankbait. These secondary factors are beyond their manufacturing control, and are chosen by the angler alone.
Over the years, I’ve watched as a competitive market has persuaded some of the crankbait companies to boldly print a running depth on the package. The resulting lesson: be careful what you wish for. Unless you are privy to the company’s testing data (line diameter used, casting distance, retrieval speed, etc) there is only a slim chance you will perfectly duplicate those characteristics. Hence, the depth given on the package may not be the running depth you experience. I prefer to see a printed range (example: runs 2-4 feet deep).
As stated earlier, the bill size and position are the primary influences affecting the path and depth a crankbait takes, but a host of other secondary factors impact a baits running depth. Such as…
LINE: One might think that the difference in water resistance between 6 pound test line and 20 pound test line would be almost negligible. Not so! Line diameter can make a significant difference in the depth a crankbait runs at.
Two anglers may be throwing the same crankbaits and yet achieving different degrees of catching success. It’s tempting to chalk the triumph of first angler to pure luck. But in reality, the successful angler may be intentionally using thinner line and getting the crankbait several feet deeper. His partner’s crankbait, however, is cruising by above their heads, never actually entering into the reduced “strike zone” of the semi-active fish. Hence, only one is catching fish; the one aware as to how line diameter is influencing his crankbait’s depth.
In their book “Precision Casting”, Dr. Steven Holt and Mark Romanack explained that a given crankbait runs approximately 20 percent deeper with 8-pound-test monofilament than with 14-pound test. Their research also says that on 20-pound test, the crankbait runs 10 percent shallower than on 14-pound test.
Stressing the importance of knowing how deep your favorite crankbaits run with different line diameters, Mike Iaconelli gave this example: Using the same casting distance, a Norman Deep Little N will run approximately…
* 7.5 feet deep on 17 lb. line,
* 9 feet deep on 14 lb. line,
* 10.5 feet deep on 12 lb. line,
* 12 feet deep on 10 lb. line,
* 13.5 feet deep on 8 lb. line,
* and nearly 15 feet deep on 6 lb. line,
Mike says that on an average we should expect about a foot and a half depth change with every line size change. (From 7.5 feet to 15 feet is significant in terms of depth variations – all due to line diameter.)
Master anglers are not only aware that line diameter affects a crankbait’s running depth – they use this knowledge to their advantage. For example, suppose largemouth bass are buried down in the acres and acres of grass fields in your favorite lake. Knowing that the grass grows to within two feet of the surface, the angler decides it might be wise to present a fast-moving shallow crankbait just above the grass. But the problem is, on 10 pound test their favorite crank runs 2.5 feet deep. In order not to be buried in the grass on every cast, an experienced angler will switch to a thicker diameter line, (perhaps 25 pound test) creating more water resistance and raising the bait the 6 or so inches desired. This “fine tuning” permits the bait to just nick the top of the grass, driving the bass wild.
Decreasing line diameter may also be advantageous in certain conditions. Let’s say the smallmouth are located on the rocky flats in 8 feet of water, but your crankbait only reaches 7 feet on 14 pound test. Perhaps you are observing that the smallies watch the bait go by, even follow it for a distance but then peal off. You may want to throw the same bait on 6 or 8 pound test allowing it greater depth in order to make contact with the bottom; remembering that a bait deflecting off structure often causes a reaction bite.
Anglers, take note: In certain situations an increase or decrease in line diameter can help “fine tune” the running depth of a crankbait and increase your productivity on the water.
While we are discussing line, the material a line is made of can also influence the running depth of a crankbait. Regular mono is an excellent choice for most applications. But one of the characteristics of mono is it has a great deal of stretch. If an angler is using a deep diver with a “worming the bait” technique (sweeping it several feet like you would plastics in a stop and go retrieve) the stretch of mono will not permit your bait to reach its potential depth. A non-stretch line, like fluorocarbon, may be the answer. Some lines float, some sink. Lead core line is often used by those who troll, because its weight increases the depths a crankbait can reach.
One could write a book on the countless ways “lines” influence fishing techniques and presentations, but in this ABC BASICS section it is enough to point out that line material and especially line diameter will impact the level of water penetration of a crankbait. This knowledge can be used to your advantage, allowing you to increase or decrease the running depths of most crankbaits.
Line diameter also has a “secondary effect” on depth, in that, thinner line casts further. And as we are about to discover in the next section, casting distance makes a significant impact on a crankbait’s running depth.
CASTING DISTANCE: Generally, longer casts cause crankbaits to run at their maximum depth. (This isn’t as dramatic with shallow runners as it is with deep divers). Why? When Ron Linder was a part of the Infisherman magazine staff, he pointed out that deep cranking required long casts. He explained: approximately 2/3’s of a retrieve on an average cast is used up in just getting a deep diver down and then back up, (1/3 down, 1/3 up). This leaves only the middle 1/3 of the cast to present the bait at its maximum DEPTH. With deep divers, a shorter cast doesn’t allow a deep-diving crankbait to reach its full depth before it has to start its way back up to the boat.
Some of the most interesting research on “Casting Distance” is found in a guide entitled “Precision Casting” by Dr. Steven Holt and Mark Romanack. The guide contains precise diving charts for 123 popular crankbaits. They concluded that the average casting distance for anglers, (throwing a 3/8 ounce crankbait on 14 pound mono), was about 70 feet. Their research went on to prove that a given crankbait runs about 25 percent shallower on a 40-foot cast than on a 70-foot cast. And a 100-foot cast allows the crankbait to dive 15 percent deeper than a 70-foot cast.
Now before a novice takes their new baitcasting reel and starts flinging their favorite crankbait with all of their might, they should be aware that it takes advanced skill to be able to cast beyond 70-75 feet. Above-average anglers may be able to reach 100 feet without creating a “bird’s nest” (often described as “a professional over-ride”), but beginners should work up to this slowly.
It’s true, some pros (equipped with long rods and top-end reels filled with light line), are able to zip a bait as far as 125 feet, but only the competitive pressures of tournament fishing would motive an angler to attempt such long distance casting. Weekend anglers with limited casting skills will find little pleasure in spending most of their day picking out “bird nests” in an attempt to get a little more depth from their crankbait. And in reality, 125 foot casts aren’t utilized by pros to increase the running depth. Long casts are primarily thrown to allow the bait to run at maximum depth in the “strike zone” for a longer period of time before they head back up to the boat. How “casting distance” affects “depth” is first and foremost presented here to prevent an angler from mistakenly making short casts with a deep diver and expecting the crankbait to reach maximum depth.
As mentioned above, casting distance can be improved by used the right equipment. When longer casting distances are desired , it is important to selecting the right rod (generally the longer rods will cast further), and the right reel (cheap reels rarely allow the smooth casting necessary for long distances). See ABC BASIC’s “RODS” and “REELS” for more in-depth discussions.
Lure design will also affect casting distance, hence depth. Some of the lighter balsa baits and longer jerkbaits tend to “propeller” in the air when cast. This spinning is a result of the bait twisting sideways while flying through the air, creating more surface drag, shortening the casting distance. Many newer designs now have internal weights in the body cavity that roll to the tail end of the bait as it hangs vertically just before the cast. Once the rod is loaded and released, the weights keep the bait flying tail first toward the target, (much like the pointed metal tip on a dart keeps it on track). Tail weighting reduces the surface resistance and increases distance. Once the bait lands on the water, the weight rolls back toward the front or mid-section of the body cavity, having no or little negative affects on the bait’s action. So, if you’re having trouble getting a lure cast far enough, try a different brand. Its different design may allow you to get the distance you desire and therefore reach the deeper depths you may be targeting.
As we’ll discover later, (in the ABC BASIC’s “CASTING”), casting distance is not just about depth. The fact is, the farther an angler can throw a crankbait, the more water they will cover, the more fish they will attract, the deeper it will go, and the longer it will be in the fish’s “strike zone”.
RETRIEVE SPEED: According to Dr. Steven Holt and Mark Romanack, (in their guide “Precision Casting”), retrieve speed has a negligible impact on a crankbait's depth. "We could demonstrate no significant difference in maximum running depths with different retrieval speeds," says Romanack. "It seems that any increased diving forces on the lure associated with increased speed are offset by equally increasing upward forces of line resistance or drag."
Unfortunately, it’s not that clean cut. It is true that a fast retrieve does not make a crankbait dive any deeper. But excessive speeds can reduce the depth a lure normally runs at, compared to moderate retrieval rates. Some time ago, Joe Hughs, (PR director for PRADCO at the time), ran some tests on the deep Wee R. Using 12 pound test line, the bait ran 8 ½ feet deep on a slow retrieve, but only 6 ½ feet deep on a fast retrieve. He concluded that most lipped baits reach maximum DEPTH at a slow wind with a medium-retrieve speed reel, or at moderate speed with a low-geared model.
When a billed crankbait begins to dig into the water, it creates turbulence. But excessive speed creates so much turbulence that it begins to decrease the bait’s efficiency to move through the water, reducing its depth. This is usually just the opposite of what the average angler expects. Those who troll crankbaits have discovered that many baits will lose their ability to track straight when retrieved too quickly and will pull to the side or start spinning.
In summary, excessive retrieval speeds will not achieve more depth, but may in fact decrease the running depth of certain crankbaits.
ROD POSITION: David Fritts, bass pro and crankbait expert, often throws crankbaits all day in 5-25 feet of water – which can be exhausting! If you watch him in a tournament, he usually is sitting down. By laying the rod against his leg, he says it helps reduces the stress of these hard pulling baits on his arms and shoulders. Comfort alone, however, should not be the only factor influencing where you position your rod tip. A savvy angler understands that rod position can and does affect a crankbait’s depth.
When a rod tip is kept above the water, most outdoor writers agree with this generalization: “Pointing the rod tip to the surface achieves maximum depth. Lifting the rod up reduces a crankbait’s depth.” According to Dr. Steven Holt and Mark Romanack, (in their guide “Precision Casting”), the level of your rod tip definitely affects the running depth of your crankbait. Their research conclusions: Drop the tip a foot, gain a foot of depth. Raise the tip 3 feet, lose a foot of depth.
The greatest depth controversy, (among angling “experts”), centers around what happens to a crankbait if the rod tip is placed below the water. Years ago, bass angling enthusiasts enjoyed watching Paul Elias compete on television because his technique in throwing a deep diver was unique at the time. Called “kneeling and reeling” – he knelt down on one knee and thrust his rod tip deep into the water, claiming that it permitted the deep diver to gain several more feet of depth. His theory and technique has been downplayed over the years by many outdoor writers as having no real impact on the bait’s depth.
But Dr. Steven Holt and Mark Romanack’s well documented research has confirmed Elia’s original claims "For every foot you shove the rod tip into the water, you gain about a foot of depth with a crankbait." It certainly is not a comfortable way to fish, and probably will not be a favorite of weekend anglers. But if you are a serious tournament angler, and big winnings are on the line, getting an extra 1-3 feet of depth with your crankbait could make all the difference.
Many experts suggest holding a rod at the 11 o’clock position after the cast. As the bait gets closer to the boat at the end of the retrieve, many pros begin to drop their rod down to the 9 o’clock position in order to keep the bait from raising up – allowing the bait to remain at the maximum depth level for as long as possible.
Summary: An angler’s rod position has a significant impact on a crankbait’s depth. This knowledge can improve an angler’s ability to keep a crankbait in the targeted depth that holds the fish.
BUOYANCY: Many of the crankbaits available to anglers come in both floating and suspending models. A few, called “countdown” lures, are actually designed to sink at a specific rate, and when the targeted depth is reached, the retrieve begins. The countdown crankbait maintains that depth until it begins to be drawn up towards the boat at the end of the retrieve. Whether the bait floats, suspends, or sinks is based on the body material, (wood or plastic), body wall and paint thickness, inserted lead weights, and additional hardware (treble hooks, metal bills, propellers, etc…)
The authors of “Precision Casting”, Dr. Steven Holt and Mark Romanack, tested models that came in both floating and suspending styles. The depth differences were significant enough for some brands to list them separately in their guide’s charts. One of my favorite deep divers, the Excalibur Fat Free Shad runs approximately 6 inches deeper in the suspending model than in the floater. However, the Wiggle Wart maintains the same depth level in both the floater and the suspending model.
In most cases, suspending crankbaits dive slightly deeper than their floating counterparts because they are slightly heavier. But the difference isn’t as significant as initially thought – often the difference is only an inch or two in depth. So no hard black and white rules apply. It’s important for an angler to know that floating and suspending members, (of the same crankbait model), may or may not reach the same depth!
Naturally the type of retrieve, combined with a crank’s buoyancy, affects the running depth. Once a crankbait gets down to its maximum depth, a steady retrieve maintains that depth. If a person changes to a “stop-n-go” retrieve, a suspending bait will stay where it is at. But a floating bait will do just that; float up. If a beginning angler is going to pause during the retrieve, they need to know whether their bait floats, suspends, or sinks if they desire to keep the bait in a depth range that is holding fish.
WEIGHTS: I suspect there are only a handful of anglers who have ever experimented with weights to alter the depth of a crankbaits while casting. Generally, the desire to reach the next depth range simply requires a change to a deeper diving crankbait. At least until the 25+ range must be penetrated. Simply put, there are no crankbaits that will reach, say… 40 feet down. (That’s why most anglers switch over to plastics on jigs, drops shot rigs, etc…)
But where there is a will, there is a way. Anyone desiring to dredge the depths with a crankbait can simply rig a floating minnow bait, (like a Rapala), on a three foot Carolina rig, using a 1 to 2 ounce sinker. You can cast and drag it through the deepest holes, offering a presentation most fish have never seen.
Lowering a 2 to 3 ounce weight on a three-way rig can take your favorite crank to any depth. If the wind is blowing in the right direction across the location or hump you’re fishing, that’s all you need to move the bait. But on windless days, speed and control is best maintained by moving the boat with an electric trolling motor. On my home lake, when smallmouth are deep (35-60 feet) – I use the 3-way rig to locate and catch them all winter long. Many large trout have also fallen to the same technique.
TROLLING: Before professional bass tournaments came about, there were a number of bass experts who had perfected the art of trolling. There was a reason for this – it was (and still is), a highly productive technique. In fresh water, trolling is a lost art in bass circles, but it has been kept alive and even improved over the years by walleye, salmon, and trout anglers. Crankbait depth in trolling is controlled by all the previous factor’s; line, speed, rod position, lure buoyancy, weights, etc… Of course, casting distance doesn’t apply to trolling, but line length does. But since trolling is a science in itself, we only mention it here in relationship to the running depth of crankbaits. (See “ABC BASIC’S: TROLLING)
“DEPTH” SUMMARY:
1) The job of every angler is to reduce the distance between the fish and the crankbait, That’s why depth is so important to an angler.
2) The water column can be divided into three depth ranges, requiring three categories of crankbaits: 1) 1-6 feet deep - Shallow divers, 2) 6-12 feet deep - Medium divers, and 3) 12 feet and beyond - Deep divers
3) The bill size and position are the primary influences affecting the path and depth a crankbait takes.
4) Generally, the larger a bill, the deeper the bait runs.
5) A bill coming straight out of the nose of a crankbait generally goes deeper that one angled downward from the body of the bait.
6) Changing the line diameter and type allows an angler to increase or decrease the running depths of most crankbaits.
7) Casting distance: Longer casts allow crankbaits to run at their maximum depth.
8) With deep divers, short casts don’t allow deep diving crankbaits to reach their full depth.
9) Retrieval Speed: A fast retrieve does not make a crankbait dive any deeper. But excessive retrieval speeds can actually reduce the depth of some crankbaits.
10) An angler’s rod position has a significant impact on a crankbait’s depth. This knowledge can improve an angler’s ability to keep a crankbait in the depth range that holds the fish.
11) Buoyancy: If an angler is going to pause during the retrieve, they need to know whether their bait floats, suspends, or sinks if they desire to keep the crankbait in a preferred depth range.
12) When fish are beyond the 25 foot range, an angler can utilize weights to reach the depths desired. (Either casting a Carolina rig, or slow trolling a three-way rig)
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