Electronics
The best trolling motor: thrust, shaft length and the battery behind it
Two published numbers pick the motor. A third one decides how long you can run it.
By Sawyer V. · Last updated · How we pick
The short answer
Budget roughly 2 lb of thrust per 100 lb of fully loaded boat, then pick a shaft that puts the motor about 12 in under the water. The Minn Kota Endura Max publishes 45 and 55 lb thrust on 12 V, 36 and 42 in shafts, and a 50 A maximum draw on the 55 lb model.
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Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Best trolling motor Minn Kota Endura Max Transom-Mount Trolling Motor 45 or 55 lb thrust on 12 V, 36 or 42 in composite shaft, 50 A maximum draw, with a battery meter built in. | Jon boats, aluminum boats and small craft on freshwater | $293.04 · Check price on Amazon #ad how this is funded · price as of October 12, 2026 |
Thrust, and the rule that actually works
The usual guideline is about 2 lb of thrust for every 100 lb of fully loaded boat weight. Fully loaded means the hull, the motor, the batteries, you, everyone else and all the gear.
| Loaded weight | Thrust needed | Published option |
|---|---|---|
| 1,500 lb | About 30 lb | 45 lb, comfortably over |
| 2,250 lb | About 45 lb | 45 lb, at the limit — take the 55 |
| 2,750 lb | About 55 lb | 55 lb, at the limit |
Round up rather than down, for one reason: wind. The rule sizes a motor for flat water, and the day you need thrust is the day the wind is pushing the bow off the spot you are trying to fish.
More thrust also costs nothing when you are not using it. A bigger motor run at half speed draws less current than a small motor run flat out.
Shaft length, measured from the bow or the transom
The motor head should sit about 12 in below the waterline. Too shallow and the prop ventilates — it pulls air down from the surface and loses its bite, which sounds alarming and pushes nothing.
For a transom mount, measure from the top of the transom down to the waterline and add about 20 in. On most jon boats and small aluminum boats that lands on the published 36 in shaft; a higher transom or rougher water takes the 42.
Too long is a much smaller problem than too short. A long shaft can be raised in the bracket; a short one cannot be extended.
The battery arithmetic, which is the real purchase
A published 50 A maximum draw and a 100 Ah deep-cycle battery gives a nominal two hours at full throttle. That is the pessimistic end, because full throttle is not how a trolling motor gets used.
At a realistic average of around 15 to 20 A, the same battery runs five to seven hours, which is a fishing day. The variable-speed control is what makes that average low.
Two things spoil the arithmetic. Lead-acid batteries should not be run below about 50% state of charge if you want them to last, which halves the usable figure; and wind raises the average draw far more than distance does.
Our marine batteries page covers the chemistry and the sizing, and the same battery usually cannot do both jobs — a fish finder on the same battery as a trolling motor sees voltage sag every time you accelerate, which shows up as sonar noise on the screen.
Transom or bow mount
Transom mount clamps to the back, steers by hand on a tiller, and is the simplest and cheapest arrangement. It suits jon boats, small aluminum boats and canoes.
Bow mount pulls the boat rather than pushing it, which tracks better and holds a line in wind, and it can be steered by a foot pedal so your hands stay on the rod. It costs more, needs a flat bow deck, and is the upgrade rather than the starting point.
If your boat has no deck to mount to, the decision is already made.
What it changes about fishing
A trolling motor is not mainly about going places. It is about staying somewhere — holding off a weed edge in a breeze, easing along a bank at the speed a crankbait wants, keeping the boat quiet over fish that an outboard would have moved.
It also pairs with sonar in a way that changes how you fish a lake. Our jon boat sonar page and installation guide cover mounting a transducer where the trolling motor will not wash bubbles across it.
So what do I actually buy?
Size the thrust from loaded boat weight and round up, size the shaft from the transom height, then budget for the battery separately — it is usually the larger surprise.
Minn Kota Endura Max Transom-Mount Trolling Motor
$293.0445 or 55 lb on 12 V with a 50 A published draw. One battery, one charger, variable speed.
#ad how this is funded · price as of October 12, 2026
Humminbird PiranhaMAX 4
$136.98A small sonar for the same boat. Run it off its own battery, not the trolling motor's.
#ad how this is funded · price as of October 12, 2026
The picks, in full
Every card below lists the specs we could read off a published page, the URL they came from, and one honest reason you might not want it.
1. Best trolling motor
Minn Kota Endura Max Transom-Mount Trolling Motor
Minn Kota
45 or 55 lb thrust on 12 V, 36 or 42 in composite shaft, 50 A maximum draw, with a battery meter built in.
12 V is the reason this is the sensible first trolling motor. One battery, one charger, no series wiring, no balancing. 24 V and 36 V systems make more thrust and cost more in batteries than they do in motor.
The published 50 A maximum draw on the 55 lb model is the figure most buyers never look at and the one that decides your day. It is what turns a battery specification into a run time, and the arithmetic is in the section below.
Two published shaft lengths, 36 and 42 in, cover most small boats. The shaft is published as composite and guaranteed for life, which matters because the shaft is what hits the rock.
Variable speed with Digital Maximizer is published rather than the stepped five-forward, three-reverse arrangement on cheaper motors. Stepped speeds waste power between the step you want and the step you get; variable control lets you run at exactly the speed that holds position.
An integrated push-to-test battery meter is published on the head. On a 12 V system with one battery, knowing what is left is the difference between paddling back and motoring back.
The drawback
It is a transom-mount hand-tiller motor, so it steers from the back with your hand on it — you cannot fish and steer at the same time the way a bow-mount with a foot pedal lets you. Minn Kota publishes the maximum amp draw but not a run-time chart, so you have to do the arithmetic yourself. There is no GPS anchoring, no autopilot and no remote at this level. And a 6 in telescoping tiller is short if you sit well forward of the transom.
Published specs
- Thrust
- 45 lb and 55 lb offered
- Voltage
- 12 V
- Shaft lengths
- 36 in and 42 in
- Shaft
- Composite, guaranteed for life
- Max amp draw
- 50 A on the 55 lb model
- Speed control
- Variable, with Digital Maximizer
- Tiller
- 6 in telescoping
- Bracket
- 10-position with quick-release lever lock
- Battery meter
- Integrated push-to-test
- Water
- Freshwater
Specs read from Minn Kota - Endura Max 55 lb Thrust, 36 in Shaft.
#ad how this is funded · price as of October 12, 2026
Questions people actually ask
How much thrust do I need in a trolling motor?
About 2 lb of thrust per 100 lb of fully loaded boat weight, then round up. Wind is what uses thrust, and the rule sizes the motor for flat water.
What shaft length trolling motor should I buy?
Long enough to put the motor head roughly 12 in under the water. For a transom mount, measure from the top of the transom to the waterline and add about 20 in. Too long can be raised; too short cannot be fixed.
How long will a trolling motor run on one battery?
Divide battery amp-hours by average draw. A 100 Ah battery at a realistic 15 to 20 A average gives five to seven hours; at the published 50 A maximum it gives about two. Lead-acid batteries should not go below half charge.
Can a fish finder share the trolling motor battery?
It can, but it is a poor idea. Every acceleration pulls the voltage down and that shows up as noise on the sonar screen. A small separate battery for the electronics is the usual fix.
Read next
Sources
Prices on this page come from the retailer at request time and change without notice. If we cannot get a live one we say “check price” rather than show you a number that has gone stale. How we pick.