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How Crankbaits Dive

By: Mark Romanack

Jake Romanack shows off a nice walleye taken trolling a floating/diving crankbait. Crankbaits are fish catching machines for those who understand the dynamics associated with trolling.

Sometimes things are not as the appear. In the case of trolling with crankbaits, most anglers think they have it all figured out. Put the bait in the water, play out some line, start trolling and the lure will wobble and dive it’s way to fishing success.

The question is how many anglers really understand the dynamics of how a crankbait functions? Below the water surface things are happening to a crankbait you may not know about or completely understand.


A crankbait achieves depth when water pressure pushing against the diving lip forces the bait to dive. In general, lures with large diving lips dive deeper than lures with more modest diving lips.

The size of the diving lip matters in terms of how deep a crankbait will dive, but there are other factors to consider including the overall weight and/or buoyancy of the lure. Buoyant lures resist diving because the buoyancy is constantly working to float the bait upwards in the water column.

The angle at which the diving lip meets the body of the crankbait also plays a role in how deep a crankbait will dive. Some crankbaits are designed to run horizontal or flat in the water, while others are designed to work with a distinctively nose down orientation in the water.

Baits that run with their nose down are generally deeper diving baits than those that run more horizontal in the water. Of course this is relative, because a bait that runs nose down in the water, but features a modest diving lip is not going to dive as deep as a lure that runs horizontal in the water but features a large diving lip.

Another factor that plays a major role in how deep a crankbait will dive is the amount of line played out or the “trolling lead” used. The longer the trolling lead that is employed, the deeper a crankbait will dive. This rule of crankbait trolling is only true to a degree. It seems for every rule in crankbait trolling there are exceptions to the rule.

When trolling with buoyant lines such as monofilament and co-polymer lines, the line floats creating a defined linear resistance to the bait’s diving ability. The buoyancy of most fishing lines is so pronounced that when line is deployed, the majority of the line played out is actually floating at or near the surface. Only a rather modest amount of line is actually pulled below the surface by the diving crankbait.

This situation creates a “bow” in the fishing line rather than the line gradually descending in a predictable angle towards the crankbait. This fact about trolling is the primary reason that using mathematical formulas to predict lure running depth are not accurate. You see, the “bow” in the line is not a constant, but rather constantly changing. As more line is played out and the trolling lead becomes longer, the amount of line associated with the “bow” becomes greater.

Line buoyancy plays a major role in crankbait function as does line diameter yet another variable that must be considered when trolling. In general, thinner lines experience less friction as they pass through the water, allowing crankbaits to in turn achieve more diving depth. Fishing lines that are thicker in diameter, create more friction in the water and therefore reduce the diving depth of crankbaits.


Most anglers have the opinion that trolling speed impacts the diving depth of crankbaits. Actually, this is only partly true. At normal trolling speeds ranging from 1.0 to 3.5 MPH changing trolling speed will not significantly change a lure’s diving depth.

In other words, a crankbait trolled at 1.5 MPH is diving to the same depth as the same lure trolled at 2.5 MPH. This occurs because the friction associated with fishing line is increased as the lure is trolled faster and decreased as a lure is trolled slower. While increasing trolling speed pushes more water against the diving lip, forcing the lure to dive, at the same time friction on the line is increased forcing the bait back to the surface. In essence, the two forces counter act one another and that’s why changing trolling speed does not significantly influence crankbait running depth.

This rule holds true for crankbaits that float at rest and dive when they are trolled. Sinking crankbaits or crankbaits that are fished in combination with sinking devices such as Snap Weights, in-line sinkers or lead core line do not apply to this rule of crankbait trolling. Lures that sink for whatever reason become very speed dependent in terms of how deep the lure will dive. Slower speeds allow the bait to achieve more depth and faster speeds increase friction thus reducing the overall diving ability of the lure.


While trolling speed doesn’t significantly impact on the diving depth of the typical floating/diving style crankbait, trolling speed does influence on the lure’s action. At faster speeds, crankbaits become more lively in the water and at slower speeds the action is somewhat reduced.

Another trolling variable to consider is how different fishing lines impact on lure action. Monofilament, fluorocarbon and also co-polymer line types feature a fair amount of stretch that works to “deaden” lure action to a modest degree. Meanwhile fused and super braid lines have zero stretch and as a result tend to personify the action of crankbaits.

This is important to understand because as water temperatures rise and fall, the activity level of fish also increases and decreases. In cold water fishing conditions when fish are often lethargic, trolling with fused or super lines can create a situation where even at slower trolling speeds the lures have “too much” action.

Certainly, anglers can catch fish in cold water while using fused and super lines, but chances are the trolling speed that produces best is going to vary somewhat from the most productive trolling speed for lures fished on monofilament.

When a fish such as this walleye is fooled completely by a crankbait it’s not uncommon to catch fish with the lure choked down the fish’s throat.


Everyone who has spent any amount of time trolling has come to the conclusion that some lures perform better at certain times than others. The credit is routinely given to the lure color, rather than other variables such as lure action or lure diving depth. Clearly lure color is one of the variables that fishermen must consider when trolling, but most anglers worry far too much about lure color.

The fundamentals of crankbait trolling success revolve primarily around lure action and lure depth. Lure color is something that could best be described as a “presentation refinement” and not something that typically makes or breaks a day of trolling.

Lure color as it relates to trolling success is largely a variable associated with water clarity and or the color or stain of the water. Certain colors of course show up better in certain stained water conditions.

While on the water experience can help in selecting lure colors that are likely to be productive, most anglers rely on “trial and error” when selecting crankbait colors. A good rule of thumb when trolling crankbaits is to switch out lure colors every 30 minutes on baits that are not productive.


Adding fish attracting scent products to crankbaits can enhance success, especially in cool to cold water conditions. All fish use scent to help them zero in on food resources.

Scents made from natural forage species are routinely the most productive as they do an excellent job of creating a natural scent stream in the water that fish are used to smelling. Unfortunately, many fishing scent products are produced with odors that are better described as “cover scents” meant not so much to attract fish, but rather to mask human and other unnatural odors.

Pro Cure Bait Scents is without question an industry leader in the production of fishing scents produced from a host of natural forage species and fish oils. Pro Cure Super Gel is an oily paste that does an excellent job of sticking to crankbaits. The natural scent stream produced by Super Gel lasts for about 30 minutes before more scent should be applied. A dab about the size of pencil eraser is enough Super Gel to get the job done.


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