The Electric Trolling Motor

for the Birding Jonboat

In my opinion, the ideal birding boat is an electric boat. While you are birding you want to blend into the habitat. The gasoline outboard engine is an obnoxious, noisy guest at the party. Electric power lets you glide silently at slow speeds.

However, the gasoline outboard is the only practical way to travel up river or reach the far end of the lake in a reasonable amount of time. So you really need both.

Of course, a canoe or kayak is another way to blend in. But paddle-craft wouldn't work for our needs. We wanted to carry lots of video and photography equipment up river as well as down river. That's hard paddling.

Canoes capsize. You can't stand up in them. Canoes often require both occupants to paddle to safely navigate around snags. And, frankly, we were concerned that our skill level and physical strength would not be up to the job.

In contrast to paddling, electric power lets one person handle steering the boat and leaves the other person completely free to photograph or observe. It's very difficult, even foolish, to try to steer and photograph at the same time. On a river, someone needs to have his full attention on steering all the time. It takes only a few seconds to get in trouble.

Fortunately for birders, fisherman use electric power for trolling, so there is a wide selection of electric trolling motors on the market. Below is the one we chose, and the rational for choosing it.

Minn Kota Vantage 24 Volt, 74 lbs. thrust, transom mount electric trolling motor
This motor is Minn Kota's newest technology and though relatively expensive, it had features we couldn't resist.

74 lbs. thrust -- Lots of power: This amount of thrust is usually overkill for the trolling-for-fish uses of a small jonboat. However, on a birding boat, the electric power is more often the main means of propulsion. Though most of the time you are going at very slow speeds, there are times when you really appreciate the amount of push that this motor delivers. For example, trying to go upstream or even holding against the current. Or trying to move quickly to another spot to get a photo. Or getting you out of trouble by powering around a snag you are getting too close to. Or crossing from one side of the river to the other and not ending up too far downstream. You can't have too much power. It's nice to have it when you need it.

Speed limits on electric power
Electric boats are slow boats. A trolling motor doesn't have enough electric power to raise the hull out of the water and plane the boat. Unless you can plane a boat, its top speed will be limited by what's called its hull speed.

Every boat hull will have a maximum speed. Here's the formula for estimating the maximum speed for a given hull. Multiply the square root of the length of the hull at the waterline by 1.3. This will give the theoretical maximum speed in knots. Most small boats will max out at 3 to 5 miles per hour. You can push harder, but you will just make more waves, not more speed.

If you push hard enough to make a boat rise up, plane, and skim across the surface of the water, you escape the limits of the hull speed formula. However this takes a lot of power relative to the weight of the boat. Though outboard gasoline motors push small boats to do this all the time, the power required makes it impractical for electric motors.

24 volt vs. 12 volt
The 74 lb. thrust requires a 24 volt system and two 12 volt batteries. 24 volts are easier on wiring and have less voltage losses. A 24 volt system does not require as large a wire to carry the equivalent current. It's a better system if you are willing to carry two batteries.

Articulated steering 4 to1 ratio: Turning the tiller will turn the direction of the motor four times as much. This makes it easy to steer. You can rotate the motor and propeller 400 degrees, giving you tremendous control.

Telescopic tiller handle: Puts the controls exactly where you need them. Most transom mount tillers are hard to reach. The speed control is an infinitely variable thumbwheel control. I find this speed control much easier to use than the usual twist-the-handle speed control on other transom mount trolling motors. I can achieve much more delicate positioning of the boat. This is important when you are trying to maneuver your partner and the bird into just the right angle for that once-in-lifetime photo opportunity.

Automatic raising and lowering of motor
The Minn Kota Vantage trolling motor has two buttons on the tiller that raise and lower the motor.

This feature didn't seem very valuable to me at first. I had never found raising and lowering the previous trolling motor much of a chore. However, in practice, I have found it extremely useful in shallow water conditions. With the push of a button, I can raise the motor to the shallowest possible operating level, with the propeller barely in the water. Set like this, you can proceed at slow speeds through shallow areas you never thought possible. And when you get to deeper water again, a push of the button will lower the prop to normal operating level.

(You can't give the prop much power when set at minimum depth like this because it is too near the surface and the prop will cavitate. It will waste power on surface turbulence, bubbling and sucking air like a kitchen blender.)

Here's another way I use this powered Up/Down feature. When I see I am about to cross over a snag, or hear a dragging sound begin near the front of the boat, I can push the Up button, quickly raise the motor, and usually avoid catching on the snag. Conveniently, pushing the Up button automatically also stops the prop. This is a wonderful feature for birding boaters who will venture into the shallowest water possible.

Transom mount vs. bow mount
While a bow mounted motor might be better for fishing, the transom mount has advantages for birding. Steering duties are all at the stern of the boat. The helmsman at the rear can steer while the passenger in front is free to observe and photograph. Also, the bow of the boat is kept free from obstructions that might interfere.

Note that the passenger and the helmsman can trade duties at any time. The electric motor, being easy to operate, can be learned quickly. Also, slow speeds are more forgiving of mistakes.

Birding by boat
The jonboat for birding
More about the jonboat and its gear
The outboard motor