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Of trolling motors

7/8/2004

Some fishing facts just make you shake your head in disbelief.

Here's a prime example: One of the first electric trolling motors in America was developed in the Moorhead-Fargo region of Minnesota and North Dakota and became known by the brand name, MinnKota. This took place something like 68 years ago.

Is that not amazing? My, how time flies when you don't need oars.

And it all came about thanks to the electric starter motor on a Model A Ford. A flexible shaft was attached, a propeller added and, presto, the Model A starter motor was turned into a fishing tool.

This brief history was provided recently courtesy of Rich Koble, an engineering supervisor with MinnKota at its Mankato, Minn., manufacturing plant.

Koble also happens to be a two-legged encyclopedia on the subject of trolling motors who thinks of things most anglers don't. For example, if a trolling motor has more thrust does it follow that it also has more speed? Well, I thought so but, of course, that was the wrong answer.

Thanks to Koble, here's more fascinating bits of info about the angling tool we've taken for granted now for nearly seven decades:

When it comes to choosing the right electric trolling motor for your needs, it's the size of the boat that matters.

"In my eyes, bigger is always better, the more thrust the better. But thrust doesn't equal speed. Thrust is power," said Koble.

He said an electric motor high in thrust power is like a bulldozer with heavy pushing power but slow in speed.

Battery life is also a perennial angling mystery. In the late 1980s, Koble said, a major engineering improvement was developed called pulse-width modulation. What it did was quickly turn the battery power on and off, upward of 20,000 times a second. Yes, 20,000 times a second.

Pulse-width modulation has been a feature in all MinnKota models as well as all other trolling motor brands since its invention.
Another invention that changed the face of trolling motors was the "weedless" prop. "Simply, the blade is designed to throw off weeds instead of wrapping itself in weeds," Koble explained.

But some things haven't changed. Koble said fishing line accidentally wrapped around the prop hub is still an evil. "Line will cut or damage the seal and allow water to invade the motor. It's still something to prevent," he said.

Another question: Is a bow mount electric preferred over a stern mounted model?

Koble said it's easier for a trolling motor to pull a boat rather than push. "A motor that pulls a boat from the bow is just much easier to control," he said.

Back to battery questions. How long will a battery last? "The daily life of a battery (in good condition) is directly proportional to the speed of your trolling motor," said Koble.

If you use high speed for a long time, the battery will die faster than if the trolling motor was operating at less than high.

Koble said it's also important to use a deep-cycle marine battery for a trolling motor and not a crank battery designed for starting automobiles. A deep-cycle battery is designed to provide high current over a long period of time; whereas, a crank battery delivers high power for short periods.

What will the next generation of electric trolling motors have to ease the time between fishing bites? Koble said he does a little daydreaming every day at work. "They pay us for that," he said.


Ron Schara may be reached at ron@mnbound.com.

Schara's 250-page book, "Ron Schara's Minnesota Fishing Guide" (Tristan Outdoors; $19.95) is available by clicking here or by calling (888) 755-3155.

July through September 2004, Ron Schara's short feature, "Backroads with Ron & Raven," airs Saturdays on ESPN2 at 7:55 a.m. ET. Click here to view this week's show descriptions.