Skip to content
0
No vehicle selected Select your vehicle
Automotive ·2 min read ·Reviewed ·By Meridian Parts

What Size Trolling Motor Do I Need? Thrust, Voltage and Shaft Length

Work out trolling motor thrust from your boat weight, choose 12, 24 or 36 volts, and pick the right shaft length for your bow.

Choosing a trolling motor comes down to three numbers: thrust, voltage and shaft length. Here is how to work out each one for your boat.

How much thrust do you need?

A common rule of thumb is about 2 lb of thrust for every 100 lb of fully loaded boat weight: the boat, motor, fuel, gear and people. Go up a size if you fish in wind, current or saltwater, or if you want to hold position with GPS anchoring for long periods.

Loaded boat weight Suggested thrust
Up to about 2,500 lb 55 lb
Up to about 3,500 lb 70 lb
Up to about 4,000 lb 80 lb
Up to about 5,500 lb 112 lb

12, 24 or 36 volts?

Higher thrust needs more voltage: 55 lb motors typically run on 12 volts (one battery), 70 and 80 lb motors on 24 volts (two batteries) and 112 lb motors on 36 volts (three batteries). Higher voltage also means longer run time at the same speed. Check the voltage on the model you choose and plan battery space and charging to match.

What shaft length do you need?

The prop must stay well under the surface, including when the bow rises in a chop. Measure from where the motor mounts on the bow down to the waterline, then choose a shaft long enough to keep the motor head about a foot below the surface. If you fish rough water, choose the next longer shaft.

Freshwater or saltwater?

Minn Kota’s Riptide models are built for saltwater; standard models are for freshwater. If you fish saltwater even occasionally, choose a Riptide.

Trolling motors by thrust

55 lb

70 lb

80 lb

112 lb

See every model on the Minn Kota page, or browse Garmin, MotorGuide and Lowrance trolling motors. Shipping is a flat $80.00 per order with 15-day free returns.

Shop parts for your application

Select your vehicle and see only parts with catalog fitment.

Find the right part

Select your application
or search by number