The Deep-Down Dirty Truth About Crankbaits

What you don't know about these lures won't hurt you, exactly. You just won't catch as many fish.

Field & Stream Online Editors

Once in a while you find yourself in the boat with a guy who looks at things from a different perspective, and you learn something new. The last time it happened to me, the boat was on a northern Ontario lake, and the guy with the different perspective was Mark Romanack. What I learned was enough to fill a book. Two of them.

Our sonar had told us that the fish were widely scattered on humps, ledges, and points, but were mostly holding at the 13-foot mark. Here's the ugly part: My companion already had three keepers in the cooler and had released two that were over the 18-inch slot, while I was still waiting to get bit (and wondering if it would be impolite to make Romanack swim back to camp so I could get skunked in peace). Just then his rod arced deeply. He threw the little motor into neutral and calmly brought in the biggest fish of the day so far, 24 inches of golden, wiggly walleye. Forget swimming. Maybe I could just whup him upside the head with the priest when he wasn't looking.

"Okay," I said. "I give up. Did you train these fish or what?"

Romanack grinned and shook his head. "We're both fishing 10-pound-test, right? You're pulling that 1/3-ounce Deep Jr. Thunderstick on about 45 feet of line. That lure runs about 10 feet deep on that line and lead length. I've got a fairly similar lure, this Yo-Zuri Hardcore Minnow. But I've got 55 feet of line. So my lure's running at 12 feet." I stared at him as if he were speaking Urdu.

He shrugged. "Walleyes are lazy, man. They'd have to move 2 extra feet to eat your bait. So they're hitting me instead of you."

"What'd you do?" I asked. "Write a book on crankbait running depths?" Actually, he'd written two: one on trolling crankbaits and one on casting them.

The Crankbait Curve
Over the last decade, Romanack-who has 10 years' experience fishing the professional walleye circuit at the national level-has spent thousands of hours observing and plotting the "dive curves" of more than 300 popular crankbaits. Being a hardheaded type, he didn't rely on secondhand information. Along with two business partners, he set up tests using a boat and a scuba diver with an underwater clipboard, positioned by a vertical measuring stick.

For the book on trolling, he made passes with the crankbaits, letting out another 15 feet of line each pass until he reached 260 feet. For the book on casting, he stationed himself in a boat; cast floating-diving lures out to 40, 70, and 100 feet (he used tetherballs as buoys, placed at 10-foot intervals on a cord anchored at both ends); and brought them in past the diver, who recorded the running depths on each pass.

The result? Hard data on exactly how deep your lure is running under various conditions. "It's like putting gun sights on your crankbait," he told me.

By now I was so intrigued I'd stopped fishing. "What about all the other variables?" I asked. "You know, how fast you're trolling or reeling, line diameter, that stuff."

To Get Deep, Go Thin¿¿¿
He saw me coming. Romanack told me the tests showed that the single most important variable affecting lure running depth is how much line you have out (or how long a cast you make). Second is how thick your line is; thinner line means less water resistance, and a deeper-running lure. (He used the most common line tests for each application, 10-pound-test mono for the trolling book and 14-pound for the casting book, and provides conversion charts in each for lighter and heavier lines.) "Problem is, most trollers don't know how much line they have out," Romanack said.

The cheap fix is to mark your mono every 10 or 20 feet with a laundry pen. That will stay on for two or three full days of fishing. Or you can get a line-counter reel, such as the ones made by Cabela's, Daiwa, and Penn for about $100. Or you can measure your average arm's length of line and keep cou, though in his experience that tends to be the least reliable measure.

The kicker? Speed has little influence on crankbaits in either trolling or casting. "We were surprised at first, too," Romanack said, seeing the look on my face. "But we found that, if anything, lures tend to run slightly deeper at slower speeds, even though the difference is a few inches at most."

Although a lure feels as if it's running deeper when trolled or reeled quickly, what you're actually feeling is water resistance. Even stop-and-go cranking doesn't significantly change the dive curve. "Sure, a buoyant lure will begin rising during the pause, but it quickly goes back down where it was when you start cranking again."

Trolling speed is important, only for other reasons. "I like to cover as much water as I can," Romanack explained. "Obviously, at 2 miles per hour, you're covering twice as much territory than at 1 mph. Generally, I like to troll as fast as I can and still get bit. That might be as high as 3 mph in freshwater. But inactive fish often seem to prefer a slower trolling speed. Lure action is another variable. Most of us instinctively select a trolling or retrieve speed that gives a lure its maximum action. Trouble is, some days the fish like a lure that runs with less wobble. You only find out by experimenting."

¿¿¿And Go Long
When setting out to write the casting book, Romanack knew that cast length would be critical, the equivalent of lead length when trolling. But cast length is infinitely variable, so he had a number of friends make what they considered to be "short," "average," and "long" casts. The results were surprising. And short. An "average" cast with a 3/8- or 1/2-ounce crankbait turned out to be just 70 feet. A "short" cast was 40 feet. A "long" cast was 100 feet. "Any farther than that and most of us wound up with backlash. And some of us are pros. With most 1/4-ounce or smaller lures, your distances are even less."

As expected, the longer the cast, the deeper the lure will run. A popular lure like the Bomber Model 6A, for example, runs at a maximum depth of 61/2 feet on a 40-foot cast, 81/2 feet at 70 feet, and 10 feet at 100 feet. Suspending models of crankbaits run a little deeper than buoyant models, but by no more than 6 inches. And they have the advantage of staying in the strike zone when paused by fish-holding structure like ledges, dropoffs, and submerged timber. Incidentally, an out-of-tune lure (see "Lure Bluffs and Blunders" on page 111) will never run to its correct depth. Nor will one that has the least bit of grass on its hooks.

The weird thing about the maximum depth zone-the sweet spot-is that it always comes during the last 12 to 30 feet of the retrieve. To Romanack, that means two things. One, you should continue cranking on the lure all the way to the boat, resisting the impulse to raise your rod tip as the lure gets close to you. Two, you may need a deeper-diving lure than you thought. To target fish in 10 feet of water 35 feet away, Romanack says, you should throw a lure that dives to 15 feet, and cast it well past the fish.

Rod-tip height, as you've probably guessed, relates closely to lure depth. Romanack did his tests from a boat with the rod tip in the position most bass anglers prefer, 18 to 24 inches off the water. Raise your tip a foot, and the lure rises a foot. Lower your rod tip a foot, and the lure runs a foot deeper. Simple.

I looked up at the sky and realized the sun had moved. It was now midmorning. I dropped my lure in the still water by the boat and began measuring off line. I happen to know that my wingspan from thumb to thumb is 6 feet. "How much line you pulling off?" Romanack asked.

"Fifty-five feet," I said. "Now let's go get me a fish." He nodded and started the motor.

Mark Romanack's Precision Casting profiles the diving characteristics of 140 popular crankbaits. Precision Trolling covers 179 baits. Each book sells for $24.95. For ordering information, call 800-353-6958; popular crankbaits. Precision Trolling covers 179 baits. Each book sells for $24.95. For ordering information, call 800-353-6958;