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Comparing 30 lb vs. 40 lb vs. 55 lb Trolling Motors

For someone who has basic knowledge, you may have heard about trolling motors with different numerical values spoken about in some angling conversations. It may have you wondering why a trolling motor has a specific weight label connected to it and what the differences between different weights mean?

It’s simple really. The main difference between these trolling motors with different weight values is the amount of thrust they can support.

30 lb vs 40 lb trolling motor

Thrust, in uncomplicated terms, is the measurement of the trolling motor’s power to push or pull. Generally speaking, the amount of thrust a boat’s trolling motor has is directly related to the boat’s weight.

You should have at least two pounds of thrust for every one hundred pounds of weight, including the weight of the trolling motor, gear, and people onboard.

Let’s do the math: a 30-pound thrust trolling motor can support up to 1500 pounds, a 40-pound thrust can support up to 2000, and a 55-pound thrust can support up to 2500 pounds safely.

If you have a trolling motor with a different weight value of thrust power, the best way to gain an accurate measurement is by multiplying the weight by one hundred before dividing it.

The main difference between the different classifications is simply the weight that these motors can support!

Air up an inflatable boat using a foot pump and an electric pump

What are the Differences Between 30, 40, and 55 Pounds of Thrust?

Minn Kota Pontoon Bow-Mount Trolling Motor (55 lbs Thrust, 48" Shaft)
Click the image for more info

The first thing to note is the amount of thrust a motor has directly correlated to how heavy a boat can be before the motor becomes unable to move it sufficiently.

For every two pounds of thrust a motor has, it will be able to move around one hundred pounds of boat weight. If you have a small boat, it may seem as though you won’t need a motor with a large amount of thrust, but you should remember that you also have to accommodate the gear and passengers on board.

However, if you have a smaller boat with a clearly stated maximum weight, you can translate that to the appropriate amount of thrust needed to move it around. For example, if your boat has a maximum weight capacity of 1500 pounds, you can get a 40-pound thrust trolling motor which can support approximately 2000 pounds in weight. (Having extra thrust is okay, but you definitely don’t want to have too little!)

  • A 30-pound thrust motor will be able to support a boat with a maximum weight of around 1500 pounds and a length of 14’
  • A 40-pound thrust motor will be able to support a boat with a maximum weight of around 2000 pounds and a length of 18’
  • A 55-pound thrust motor will support a boat with a maximum weight of about 2500 pounds and a length of 21’

How Fast Can a 30, 40, and 55 lb Thrust Trolling Motor Go?

MinnKota Edge 55 Bow Mount Trolling Motor (55lbs Thrust, 45" Shaft)
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Aside from supporting a boat up to a certain weight, other factors are considered when comparing the different trolling motors and their thrust values.

One of these qualities, and a very important one at that, is the speed that the trolling motor can support based on its thrust — which is dependent on the weight of the boat.

However, something that you may not have expected is that regardless of the thrust value of the trolling motor, the maximum cutoff speed is always five miles an hour. The speed cutoff may have you thinking: why spend more money on a 55-pound thrust trolling motor when the maximum speed is 5 miles per hour no matter which sized trolling motor you purchase?

It is true that the 30 lb, 40 lb, and 55 lb thrust trolling motors all top out at 5 miles per hour, but you will need the larger-sized motor when you have a larger boat. If you don’t, your boat will not be able to hit anywhere near the maximum speed.

Pro-tip: When considering the weight of the boat, don’t forget to include the weight of the gear and people that will also be on board.

How Much Horsepower is in a 30, 40, and 55 lb Thrust Trolling Motor?

Minn Kota MAXXUM Trolling Motor (40-lb Thrust, 36" Shaft)
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Like the thrust value in these different motors, they will have a varying amount of horsepower depending entirely on the importance of that thrust.

If you want to calculate your motor’s horsepower, there is a pretty simple formula that you can easily follow! The formula is:

Thrust (pounds) * vehicle speed (mph) / 375

Assuming that you purchased a trolling motor that can support your boat well past its standard weight, you can always put the vehicle speed down at five miles an hour, leaving the only other value in the formula you need to find is the thrusting weight.

If your boat’s maximum speed is less than 5 miles per hour, you can plug in the speed that your boat can move at while the trolling motor is at maximum power to determine its highest horsepower value. With this, you should be able to calculate the horsepower of whatever trolling motor you own or wish to purchase for your vessel!

Using the formula above, the HP for each of the motors is:

  • 30 lb motor = .36 HP
  • 40 lb motor = .53 HP
  • 55 lb motor = .73 HP

Which Trolling Motor Should I Get if Two Different Motors Can Work with my Boat?

PEXMOR Electric Trolling Motor 55LBS Thrust
Click the image for more info

Say, for example, that your boat’s minimum to maximum weight range happens to overlap between the effective weight range of two different trolling motors. You may then find yourself asking, should you save money and opt for the lower thrust trolling motor?

Most boating experts would recommend purchasing a motor that you know will perform up to standards regardless of the boat’s weight, rather than buying a weaker motor that will constantly be overworking.

While they may both technically have enough power to pilot your boat, the weaker motor will be running at maximum all the time to keep pushing the boat forward. If an error were to occur causing the motor to no longer work at peak capacity, you might find yourself unable to pilot the boat.

While the same error may happen to a stronger motor as well, you will have much more breathing room in terms of functionality since the more powerful motor will be able to pilot your boat without running at maximum capacity.

Is There an Advantage to Running a Two-Trolling Motor Setup?

There is no clear advantage to running a two-trolling motor setup. The main reason you want to run a two-motor setup is if you are going on a more extended excursion and want to be prepared if one motor fails.

However, by taking reasonable and proper care of your motor, you shouldn’t have to worry too much about that possibility.

Aside from having a backup, there aren’t many other benefits to having two motors. First off, you won’t be going any faster by running two motors, as every trolling motor has the same maximum speed. On top of that, having two motors running simultaneously will only cause your batteries to drain much faster since twice the amount of power is being used to gain the same results.

That being said, unless you have an apparent reason where having two trolling motors on your boat is necessary, it would be in your best interest to stick with only running one motor and save yourself a fair amount of money in the process.


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