Trolling Motor GuideBy Randy Tucker | Updated:
Trolling motors have come a long way since O.G. Schmidt adapted a Ford Model A starter to a submerged propeller-driven shaft near Fargo, North Dakota back in 1934. Trolling motors today come in a wide variety of sizes powered by 12, 24, and 36-volt direct current batteries.
While there is no “one size fits all” guide to purchasing the right trolling motor for your application, there are some things to consider. In this review of trolling motor features, we’ll walk you through all the necessary components it takes to find the right trolling motor for your boat, and you’re style of fishing. You can also check out our trolling motor size chart to select the appropriate trolling motor.
Here is an outline of the terms we’ll describe in greater depth later in this review.
Trolling motor considerations:
- Hull shape
- Types of motor mounts
- Shaft length
- Water conditions
- Speed of troll
- Fresh vs. saltwater trolling
The key term for every trolling motor user regardless of the size or shape of their boat is thrust. Thrust is the force that drives a boat through the water, and it is an integral component in determining what size trolling motor you should buy.
Thrust is measured in pounds of force in the water. For a small boat, just a dozen or so pounds will move you easily through the water at speeds up to three miles per hour. For larger, deep well, or heavy pontoon boats you’re going to need a lot more pounds to push your watercraft at the trolling speed you’ll need for walleye, salmon, or any other species you can troll for.
The Rule of Thrust
A simple rule to follow is to add two pounds of thrust for every 100 pounds of boat weight. It is wise to note, that boat weight isn’t measured in an empty boat, but rather in one fully loaded with equipment and with the body weight of the people in the boat added to the calculation.
Here is an example of what that means in practical terms.
Shallow hulled 12-foot aluminum fishing boat. Two anglers, 125 pounds of gear including tackle boxes, 12-volt battery, and cooler.
- Boat weight: 240 pounds
- Angler weight: 410 pounds
- Coolers/batteries/tackle weight 150 pounds
- Total weight 800 pounds
At two pounds of thrust per 100 pounds that means you’ll require a minimum of 16 pounds of thrust to move the boat on still water. Remember, that’s the minimum. As with any propulsion device, if you want to go faster you need more power. In a car, truck, or gasoline-powered boat motor that power is measured in horsepower, in a trolling motor, it is measured in thrust. The higher the thrust the greater the speed, and the greater control you have in windy conditions, or in choppy water.
A boat’s hull has several purposes, the primary one is flotation, but secondary purposes are for stability in the water, guidance and control, and the ability to navigate shallow water. To put it mildly, there are a lot of hull designs, but we’ll take a look at just the main ones.
Types of Boat Hulls:
- Displacement Hull
- Planning Hull
- Flat bottom Hull
You see these hulls on large merchant ships and river barges. The name describes their primary purpose, to displace a lot of weight. You’re not likely to have this type of hull in conjunction with a trolling motor, but in large commercial fishing applications, you will see these occasionally. They require a lot of power to negotiate and aren’t a good choice for the standard recreational uses you’ll find with most trolling situations.
Think of bass fishing tournaments and you’ll soon discover the relationship between trolling motors and planning hulls. With bass competition you’ll find low-lying, planning hull boats with huge motors that get on top of the water and race to prime fishing areas sometimes in excess of 60 mph. On those same boats, you’ll see retracted trolling motors ready to be dropped into the prime bass areas once that high-speed boat arrives at the location.
Most planning hulls use a foot-operated transom on the trolling motor so the angler can fish unimpeded and guide the boat with their feet.
The trolling motor can be front or rear mounted
Flat Bottom Hull
This is the most common application of the trolling motor. A flat bottom hull gets you into shallow water, along reed beds, cattail outcroppings, and heavy shoreline foliage, the places you’re likely to discover perch, bass, and late-season walleye. Sometimes a trolling motor is the only motor on a flat-bottomed boat since they have very low resistance in the water and are so easy to manipulate. Most flat-bottomed boats have the transom attached at the rear of the boat with a simple handle that an angler can use to turn the boat in the water. A heavy 12-volt battery will be placed near the middle of the boat so weight is displaced correctly.
Similar to the planning hull but designed to stay in the water for extra stability rather than power up or “plane” on the surface at high speed. These hulls are found on combination fishing/recreation-style boats. A trolling motor works at an angle to the V-hull, creating slower, but much more stable movements than you’ll find on a flat-bottom hull. They can be manually guided at the rear of the boat or have a foot-pedal operated transom on the rear to free up the operator's hands.
Pontoon boats have the reputation as party barges, and they can be a lot of fun, but when properly equipped with the right trolling motor they can be even more enjoyable as floating fishing docks. The wide platform and stability of a pontoon lend themselves to all types of angling. A powerful trolling motor, placed at either the front or rear of the pontoon can get your boat into a perfect position to throw poppers for bass or to just troll along beds of perch, trout, or walleye. In many ways, a trolling motor on a pontoon is one of the best applications for both.
Everything said about a pontoon is true for triton as well. A tritoon is similar in design to the two-parallel floats that compromise a pontoon, the only difference being the third float down the middle of the boat. The third float makes trolling a bit trickier with the trolling motor needing to be offset, rather than in the center of the bow or stern. This makes guiding the tritoon more of a challenge since it will pull to one side with resistance from the three pontoons. After a few minutes of experimenting the guidance will quickly come around.
It might not be much of a shock (sorry, bad pun) but voltage is always an indicator of higher potential power. A 12-volt system set on maximum will provide the same thrust as a 36-volt system set at a much lower level, but the considerations in determining voltage are potential power requirements.
More voltage means more potential power. A large fishing boat can be moved with a lightweight 12-volt trolling motor, it just won’t move very fast.
If you want the ability to move a larger boat just as easily as you do a small 12-foot flat-bottomed boat, you’ll need to invest in a more powerful 24 or 36-volt trolling motor.
All three voltage motors use standard 12-volt marine batteries. The 12-volt models use just a single battery while the 24 and 36-volt motors require two and three batteries respectively tied together to provide the necessary voltage.
Thrust Range of 12, 24, and 36-Volt Trolling Motors
- 12-Volts up to 55 pounds of thrust
- 24-Volts 68-86 pounds of thrust
- 36-Volts over 100 pounds of thrust
Boat Weight/Size/Trolling Motor Requirements
|Boat Weight (lbs)||Minimum Thrust||Voltage||Boat Length (ft)|
|Less than 1500||30||12||14|
|1500 to 2000||40-45||12||15-18|
|2000 to 2500||50-55||12||12-21|
|2500 to 3000||70||24||23|
|3500 to 4000||80||24||25|
|4000 to 5000||101-112||36||25+|
Types of Trolling Motor Mounts
When it comes to mounting a trolling motor on your boat there are only two choices, either front or back, or in naval terminology bow or stern. While the choices are limited, the decision remains a complex one for many trolling motor applications.
There are positives and negatives to both bow and stern mounts, with the type of fishing, and the conditions you’ll find in terms of chop, wind, and shoreline topography all being considerations.
Rear/Stern Mounted Trolling Motors
If you’ve been on the water awhile, the odds are that this is the type of trolling motor you grew up with. The motor is mounted to the transom by a clamp or bolt system next to the outboard motor and an extendable handle lets the operator adjust speed and direction while sitting at the rear of the boat.
The benefits of a stern-mounted, hand-controlled trolling motor are much more apparent in a small boat. A shallow draft, flat bottomed, or shorter-length traditional v-hull aluminum boat is ideal for a rear-mounted trolling motor.
With a single angler in the boat, the weight is distributed to the stern, with the 12-volt battery set as far forward as possible to keep the boat balanced. This arrangement allows an angler to get close to shore and with the bow raised the boat can get into very shallow water. With another angler or two in the boat, the weight is more evenly distributed and the boat will draw more water, making it more stable but having a deeper draft.
Twisting the handle on the trolling motor left or right several notches adjusts the speed and the direction of the thrust.
If you’ve ever fished along a shoreline covered by heavy brush, with willows, cattails, and other shrubberies right on the edge of the water you soon learned how important it is to have both forward and reverse on your trolling motor.
When you get a spinner, jig or topwater lure snagged in the brush along the shore the trolling motor lets you move right next to the lure allowing you to easily retrieve it. A rear-mounted trolling motor is ideal for a single angler in this situation since they can back up to the snagged lure, release it and easily switch the thrust to forward and they’re off to the next spot.
Foot Operated Rear Trolling Motors
While 12-volt systems are offered in both manual and foot control applications, larger 24 and 36-volt trolling motors are almost always operated with a foot control.
The advantage of a foot control on any boat is the hands-free nature of the system. With just your foot you can change direction, angle, and speed while keeping your hands on the rod and reel. The action takes a bit of coordination but once you master it, you can keep your lure in the water as easily as everyone else in the boat. Another benefit is since you’re operating the trolling motor you get to decide who has the best angle at that sweet-looking spot just ahead.
Foot controls are more expensive and require more space than a manually operated trolling motor but the benefits on a mid-sized boat more than compensate for the loss of space.
On a small boat, you’ll need to decide if the rear foot control is better, or if the less expensive, hand-operated motor is more to your liking.
Front/Bow Trolling Motors
It’s been almost a century since the first trolling motor hit the water. That original version was rear-mounted, but in recent years the bow or forward mount has gained popularity.
They aren’t suited to v-hull or planning hulls since they have to be mounted on one side of the pointed bow and are more difficult to guide, but they’re outstanding on pontoons, flat bottomed “John Boats” and on the specially design bows of high-speed bass boats.
A bow mount allows you to pull rather than push your boat through the water. This takes the guesswork out of how to move the angle of the motor at the last second to get the bow properly placed.
Just point the motor towards the target and the boat will follow in front mounted trolling motor.
The disadvantages come when fishing shallow water near the shore. With a bow mount, you’ll reach shallow water with the motor before the rest of the boat arrives. That’s why many anglers prefer a stern mount when working shallows for bass or perch.
Another disadvantage is having the outboard motor at the stern and the trolling motor at the bow. This isn’t a problem with two or more people in a boat, but a single operator would never place motors in this configuration unless they wanted to spend a lot of time walking back and forth on the rocking boat.
Foot Operated Bow Mount Trolling Motors
The foot-controlled, front mount trolling motor on a pontoon boat borders on art when used properly. Nothing gets you into and out of shallow fishing spots like a bow-mounted trolling motor on a 20 to 24-foot pontoon boat.
Pulling the boat rather than pushing it through the water takes all the mental calculations of a rear-controlled motor away, leaving you with just a few taps of the foot to get the perfect angle for a cast into a great-looking bass habitat.
The only caveat on a front-mounted system with a large pontoon boat is the power drain. If you’re using a 12-volt motor, with the foot-mounted system tied to the same battery you’re going to draw a lot more amps than a hand-operated motor. The solution is a separate battery for the motor and another for the control.
Unless you’re moving constantly, while perhaps fighting a strong current or a gusty wind, you should have more than enough power in your battery for a full day on the water.
On a bass boat, the raised seat in the bow is perfect for a front-mounted, foot-operated trolling motor. Professional bass tour anglers rely on this system to get them in position quickly. When the game is to get as many bass as you can in the shortest amount of time, this labor and time-saving innovation is often the difference between winning and losing.
One thing to remember on both a bass and a pontoon boat is to raise the trolling motor before you start the main engine. You’ll get some strange patterns on your boat when you hit the gas with a front-mounted trolling motor still in the water. In the worst case, you can snap off the shaft or damage the propeller on your trolling motor if remains in the water.
Ideally, you want your trolling motor as deep in the water as the conditions allow. With that being said, the conditions are rarely ideal. A strong lake current requires the most thrust you can generate and to deliver that maximum your motor performs better a few feet below the surface than it does at shallower depths.
If you’re working the shallows on a prime bass area, you’ll want the motor just a few inches below the surface, so the shaft length doesn’t matter as much in these conditions. Add in the height of the mounting bracket from the surface of the water and the requirements for a good shaft length can vary greatly.
On a small 12 to 16-foot aluminum boat, you’re only a few inches above the water, so any length shaft will work. On a larger pontoon, big v-hull the deck where the motor is mounted might be three feet or more from the surface, which requires the maximum length shaft you can find.
On larger 12-volt, and most 24 and 36-volt systems the mount is usually hinged so the longer shaft can come out of the water and be stowed on the front deck of the boat. This takes a surface area away from the deck, but the ease of dropping a longer shaft trolling motor into the water more than compensates for the loss of space.
Those televised bass fishing tournaments would have you believe that every time someone goes fishing it’s going to be a nice, clear, partly cloudy day with no wind, rain, hail, or strong cross currents. The truth is far removed from that fantasy.
Water conditions can not only be unpredictable but can change in a matter of minutes. When you have a weekend to fish, you don’t want to have to get off the water because your trolling motor can’t handle the conditions. You need to be aware of what might be out there and be prepared for it.
Wind is notoriously bad with a high-profile boat like a pontoon or tritoon. These big boys with their larger decks, awnings, and seating are virtual floating parachutes in even a moderate wind. A trolling motor will be tested to the maximum unless you have one with the power to handle the wind. While the wind isn’t as big a factor on lower profile boats like flatbottomed, smaller planning hulled boats, and bass boats, the current can be.
On the surface, it might seem calm and pristine, but often a lake will have strong currents flowing through it. If you’re fishing a reservoir near a large dam, the natural flow of the water towards the spillway will pull you towards the dam. It takes a powerful trolling motor to compensate for both the force of the wind and even more so for the force of moving water.
If you know the potential conditions you might face, have a trolling motor with a thrust rating much higher than is necessary for your boat in ideal, calm conditions.
Speed of Troll
This is a factor directly tied to the type of fishing you’re doing. Trolling at two or three miles an hour is a fast troll, but sometimes, especially when trolling for trout, you need that speed to keep your spinners and spoons dancing in the water.
At other times, the trolling motor is just a way of maneuvering your boat into a tight fishing spot. Trolling at slow speeds allows anglers to cast and retrieve over a large area of water at right angles to the boat’s path. This allows a boat with several people fishing to work large areas of a lake. It’s a good practice to follow if you’re new to a lake and just literally testing the waters.
At other times, you might know where structure brings in big schools of perch, or where a trench extends along the middle of a lake. In the summertime, the water temperature in these trenches makes them a perfect spot for walleye to suspend and wait for baitfish to swim by. By timing the speed of your trolling motor and presenting your lures at the correct speed, you’ll increase your chance of success dramatically.
On large lakes or the ocean, cross currents, wind, and even tidal flow can all be compensated for with the speed of the troll.
Bigger boats, need higher thrust, that’s the rule to remember when trolling in these conditions.
Fresh vs. Saltwater Trolling
First for the detractors who will use the same trolling motor no matter the type of water. Yes, a freshwater trolling motor works just fine in salt water, at least for a while it does.
If you’re fishing on Lake Michigan or Superior, the conditions aren’t going to be that different than working the waters off the South Carolina or Oregon Coast. You’ll encounter wind, fast-moving squalls, and strong hidden currents on the Great Lakes just as you will in the ocean.
The difference comes in the corrosiveness of saltwater versus the relatively benign effects of freshwater on a trolling motor.
Saltwater is corrosive, the salt content eats up freshwater fishing reels, rods, and the hulls of boats at an impressive pace. It is even more apparent in a trolling motor.
Saltwater has such a corrosive effect on a trolling motor that a freshwater trolling motor used in saltwater will void the warranty.
The major manufacturers of trolling motors are well aware of how fast saltwater can damage or destroy their freshwater motors and will inspect the motor if you try to return it under warranty to see if it's been in the ocean. (yes, they can tell)
Specially designed saltwater trolling motors feature more corrosive resistant materials such as brass, stainless steel, and high-impact corrosive resistant poly carbon components.
If you’re planning on fishing the bays, estuaries, and possibly even the open ocean, buy a saltwater trolling motor. They’re more costly, but in the long run, they’re more cost-effective due to their longer durability.
Trolling motors are one of the greatest innovations ever conceived for boat fishing. They can offer lures at a constant rate when trolling across a lake or bay, or they can just get you into position to cast from your boat quietly.
A paddle can do the same thing, but they’re noisy in comparison to the stillness of a battery-powered trolling motor.
One final note on trolling motors is their role as backup propulsion in the event of a failure by your gasoline-powered main motor.
Many anglers have crept back to the dock on the power of a trolling motor. No, you won’t come in screaming at 45 miles per hour, but you will come in.
That’s the important thing.