What to Look for When Buying a Trolling Motor

Buying an outboard motor is pretty straightforward, but buying a trolling motor is not as simple. Trolling motors are used for stealth, so a smaller, less powerful trolling motor that creates less noise and turbulence is far more desirable. 

Trolling motors buyers guide

With that in mind, here are the things you should look for when choosing a trolling motor for your boat.

Buy a trolling motor

Buy trolling motor parts

Trolling Motor Thrust

Thrust is the power rating of the trolling motor, measured in pounds. Although the trolling motor needs to generate enough thrust to propel the boat, you don’t want a motor with too much power, as it may disturb the fish and thus negate the purpose of having one for … well, fishing!

Trolling motors guide

The ideal trolling motor has enough thrust to get the boat up to about 4mph. It should keep the boat stationary over a specific point, even when there are moderate winds, currents or swells. To determine the thrust you’ll need from the trolling motor, you need to factor in the following:

Boat weight. Calculate the combined weight of the boat, all the passengers and a full load of gear. You’ll need a minimum of 1 pound of thrust for every 50 pounds of weight. For example, if the total weight of the boat, passengers and gear is 1,500 pounds, you’ll need a trolling motor with at least 30 pounds of thrust (1,500lbs ÷ 50lbs = 30lbs).

Fishing conditions. If the conditions where you fish (current, wind, swells) often affect the attitude of the boat, you’ll need to account for this by adding a few pounds of thrust to the trolling motor.

Trolling motors fishing

Motor voltage. Trolling motors are available as 12V, 24V and 36V units. The more voltage the trolling motor consumes, the more thrust it generates.

Trolling motor weight/thrust infographic

NOTE: These are only approximations, and you’ll need to calculate an accurate weight for your boat as outlined above.

Power Consumption

Trolling motors are powered by electricity, so the more thrust the motor generates, the more electrical power it consumes. 

Trolling motor electrical power

A trolling motor requires one battery for each 12V of power it consumes. To determine the ideal trolling motor voltage, you’ll need to factor in the following:

  • Motor run time. The more batteries the trolling system has, the longer running time you’ll get from your motor. This is important if you intend to fish for hours on end.
  • Battery storage. More batteries means more space required to house them. It might not be practical to install multiple batteries on a small boat to feed the increased power consumption of a higher-voltage trolling motor.

The following table gives you the ratio of trolling motor voltage to number of batteries it requires.

Trolling motor battery voltage chart

Shaft Length

The trolling motor must have a shaft long enough for the propeller to be fully submerged. This maximizes the motor’s performance, and minimizes prop noise and turbulence.

Trolling motor shaft length

The shaft should be long enough so that the central axis of the prop shaft is about 1 foot underwater in calm conditions. To calculate the correct shaft length for your trolling motor, measure the point the shaft will begin once the motor is mounted to the boat, down to the water. Next, add on the length of shaft required to submerge the prop shaft to about 1 foot below the water. If you fish in rougher waters, add more shaft length to account for the swell. 

Johnson Endura Max trolling motor

Johnson Pump trolling motor

Johnson Pump power drive trolling motor

Bow-mounted trolling motors pull the boat through the water, which makes them very maneuverable, providing high-precision control over the boat.

Transom-mounted trolling motors push the boat through the water. They’re not as maneuverable and offer less control, but they’re good to have as spare motors in case the outboard or sterndrive fail.

Advanced Trolling Motor Features

Modern trolling motors have evolved with more advanced features. Of course, the more options you want, the more expensive the motor, but also the more effective they are for better fishing

Trolling motor outboard

  • Autopilot. Keeps the boat on a particular route with automatic corrections for winds and currents. Most autopilot systems are controllable with a smartphone app.
  • Electric steering. Allows for more precise maneuverability compared to cable-steering trolling motors, and enables the user to control the unit from anywhere on the boat.

If you’re on a budget, there are quality affordable trolling motors that will only set you back a couple of hundred dollars or less. Boats.net has a large selection of trolling motors at great prices, so be sure to check them out.


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