Understanding Trolling Motor Thrust

Unlike an outboard motor, shopping for a trolling motor is less about how much power it produces and more about how quiet or stealthy it is.

Trolling motors are mainly used for fishing, so the less the motor scares the fish away, the better. Before buying a trolling motor, aside from shaft length and whether it’s a cable or electric steer, you should know about the motor’s thrust. 

Trolling Motors: Power vs Thrust 

While outboard motors are rated by power output, as measured in horsepower, trolling motors are rated in thrust output, as measured in pounds.

Thrust equals power, but getting the trolling motor with the most thrust isn’t necessarily a good thing. Unlike an outboard motor, which needs power to quickly get your boat up on plane and hold it there on wide open throttle, a trolling motor is all about slow, stealthy movement.

The motor should be powerful enough to maneuver your boat over your fishing spot of choice and keep it there despite waves, wind or currents. For most boaters, this means a trolling motor with enough power to get their boat up to a few miles per hour. 

Trolling motors should be quiet, and generate as little prop wash as possible to avoid scaring fish away. So the smaller the motor, the better, especially since you have to store it onboard.

Calculating Trolling Motor Thrust

The perfect trolling motor should be able to get your boat to about 5 MPH at the most. Anything more powerful will likely spook off the fish.

To calculate how powerful your trolling motor should be, you need to know the weight of your boat plus the weight of people onboard plus gear. You can find your boat’s weight in the owner’s manual, or through a quick online search. 

Once you’ve calculated the combined weight of your boat, the people and their gear, you can determine the trolling motor’s power using the following equation:

• 1 pound of motor thrust for every 50 pounds of combined weight

For example, if the combined boat/gear/people weight is 3000 lbs, get a trolling motor with 60 lbs of thrust (3000 lbs ÷ 50 lbs = 60 lbs thrust).

If you encounter waves, wind or currents often that affect the altitude of your boat when you’re fishing, consider adding about 10 lbs of thrust to the trolling motor calculation.

The following table gives you an approximate idea of ideal trolling motor thrust compared to boat size. 

NOTE: These are only estimates, but should give you a good benchmark to narrow down your list of suitable trolling motors.