Trolling Motor Thrust Guide

What Is "Trolling Motor Thrust"

Arguably the most important consideration when you are looking for the right trolling motor is how much thrust your boat will need.

Thrust (measured in pounds lbs) is the standard measure of how powerful a trolling motor is. The larger and heavier your boat, the more thrust you'll need to achieve satisfactory results on the water. Conditions such as wind and swell also play a role in determining the appropriate thrust for your trolling motor.

Trolling motors come in three voltage ratings: 12v, 24v and 36v. Motors with higher voltage have more thrust. Some of the newer brushless motors such as Garmin's Force Kraken or Minn Kota's Riptide Instinct QUEST are "dual voltage" which means you can wire the motor at 24v for roughly 90 lbs of thrust or 36v for roughly 110 lbs of thrust.

If there's one thing you want to avoid, it's purchasing a trolling motor without adequate thrust and voltage.

Conversely, there is such a thing as too much thrust. Installing a 36v motor on a kayak for instance would be dangerous. An overpowered motor will turn your boat very quickly and could lead to an "overboard" type of situation.  

A common misconception about thrust is that it will provide higher speeds which is not necessarily true. In many ways, thrust is similar to "torque" in a car; it's about "pull and twist," not top-end speed.

Adequate thrust level is of particular importance if you purchase a trolling motor with GPS functionality like Minn Kota's i-Pilot GPS or their new Advanced GPS System. These motors with GPS auto navigation features like "Spot Lock" are designed to keep your boat in a fixed position or on a steady course. For instance, if your trolling motor does not have enough thrust, it will struggle to keep your boat where you want it if wind or current kicks up. 

In addition to poor performance and GPS accuracy, having too little thrust will reduce motor run-time and put stress on the motor because it's working too hard. When a motor has to run at higher speeds to compensate for too little thrust, it produces higher friction and heat which can also shorten the lifespan of your motor.    

A Trolling Motor With Adequate Thrust For Your Boat Should Perform As Follows:

• Provide responsive steering and acceleration 
• Cruise at roughly 3-4mph with 50-60% throttle (may vary based on conditions) 
• If equipped with GPS, your boat should be able to hold on a spot or heading regardless of wind, swell or strong current
• Does not require the highest prop speed to maneuver your boat
• Offers enough run-time for a typical day of fishing

Nothing kills a day on the water quite like a trolling motor that does not have enough thrust to get you through an average day on the water (3-5 hours of continuous run time). Prior to purchasing a trolling motor, we highly recommend following the instructions below to determine the appropriate voltage and thrust for your boat.  

How To Determine The Right Amount Of Thrust For Your Boat:  

Boat Weight 

Boat weight is the most important consideration to take into account when choosing a trolling motor. A beginning rule of thumb is that you want a minimum of 2lbs of thrust for every 100lbs. For example, if you have a 3000lb boat, fully loaded, then the calculation is (3000/100) x 2 = 60lbs of thrust. 

When calculating boat weight, make sure you calculate the heaviest potential weight which includes a boat fully loaded with gear, fuel and the maximum number of passengers.

Hull Design

The other factor that plays a role in thrust determination is the size and shape of the hull. When turning, a Deep V hull will have more drag than a flats boat or a Jon Boat. As a result, a trolling motor will have to work a bit harder on some hull types than others.

Another good example would be a Pontoon Boat. Due to the shallow draft and low drag, a 10 year old child can push your pontoon boat away from the dock...gulp. However, when on the water in a breeze, a pontoon can be very tough to keep in a fixed position which is why you need the adequate thrust.    

When in doubt, assume your boat will be fully laden and add a few pounds just to be conservative. Within reason, you cannot have too much thrust but you can definitely have too little!  

Not sure how much your boat weighs?  The easiest way to find out is to look up your boat in the JD Power boat directory, which lists boat weights for thousands of boats and is organized by manufacturer, model and length. Keep in mind that the listed weights on JD Power are the dry weight of the boat and not the max weight.

Fishing Conditions Such as Wind and Current

Conditions should also play a significant role when calculating the right thrust for your trolling motor. If you typically fish or cruise on smooth lakes with no current, you should be able to stick to the listed minimum thrust. However, if you often fish in fast moving water, strong winds, swift current or swell, you'll definitely want to move up a level in thrust to ensure ample torque and performance from your trolling motor.

The Relationship Between Voltage and Thrust

As we mentioned, trolling motors come in 12v, 24v and 36v as well as the brushless motors with dual 24v/36v voltage. The higher the voltage, the greater the thrust.

Brushless motors such as the Garmin Force Kraken offer dual voltage capability which enable you to choose either 24v or 36v configuration depending on your boat's thrust requirements.   

For flooded lead acid or AGM batteries, a 12v motor requires one dedicated battery, a 24v requires 2 dedicated batteries and a 36v requires...you guessed it, 3 dedicated batteries. 24 or 36v motors running lead acid or AGM batteries must be wired in series. Take a look at our battery wiring diagrams for proper wiring instructions.

Deep cycle lithium (LiFePO4) batteries are becoming increasingly popular because can produce 24v-36v from just one battery.

In general terms voltage/thrust ratios are as follows:

12v motors = 55 lbs of thrust or less

24v motors = Over 55 lbs up to 90 lbs of thrust

36v motors = Over 80lbs up to approximately 115lbs of thrust 

If you want the ability to fish for multiple days without recharging, you'll also want to consider stepping up to a motor with higher thrust/voltage.

Moving from a 40lbs 12-volt motor (requiring one battery) to a 80lbs 24-volt motor (requiring two batteries) on the same boat will provide you with significantly more run time. For more details on understanding and calculating run time, please see our guide on Calculating Motor Run Time. 

Boat Specific Thrust Charts

To help you select the appropriate thrust for your boat, we've assembled thrust recommendation charts for individual boat types below. The thrust portions highlighted in yellow represent the most effective thrust range for each specific boat given its common use, weight and application. Please note that while boat weights and lengths have been adjusted for individual boat types, these are estimates only. For more information to help you make a purchase, please grab our FREE Trolling Motor Buyer's Guide or call us at 800-472-3509.