Updated: Apr 15, 2021
I kayak a lot—mostly on lakes, flatwater rivers, and sounds. My primary boat is a 2007 14’ Wilderness Systems Pungo 140 that I found on the local used market. It’s a great recreational sit-inside with a spacious cockpit and tons of storage. With its V-shaped hull, it’s pretty fast and tracks dead straight, but can be a bear to turn. Also due the hull shape, it freely rocks side to side, but once rocked, has great secondary stability. After 5 years and hundreds of miles, I’ve still never managed to flip it. I use this boat for basically everything other than whitewater, from the mountains to the coast.
Anyway, the main shortcoming of my boat is that it runs on manpower. And as much as I love paddling, sometimes I’d rather save my energy or have my hands free for other important tasks (e.g., binoculars, cold beverage, etc.). So, after battling wind and current on a recent trip to Wrightsville, I decided to install a trolling motor.
As you might expect, I did a lot of research before pulling the trigger on this project. And even after all my research, I wasn’t sure whether it would work or not (spoiler alert: it works great). The main issue is my boat: it’s not the type of kayak that lends itself to a motor. Scouring the internet, essentially all motor-powered kayaks are sit-on-top fishing kayaks, which are better suited for two main reasons. One, fishing kayaks have flatter bottoms and much more primary stability than my boat, which is important when you’re hanging a 25 lb motor off one side. Two, fishing boats also generally have a flat deck (top surface), providing for a relatively simple and secure motor mount. My boat has a contoured deck, so I had to create a custom mount.
But before I dive into the fun stuff (creating the custom mount), let me run through the ingredients list.
First, you need an electric trolling motor. There are a few variables at play, including the power, shaft length, and saltwater capability. I went with a Newport Vessels motor with 36 pounds of thrust (plenty power for my kayak, and much better on battery consumption than a 55 lb model), a short 24-inch shaft (ideal for kayaks), and saltwater tolerance. I’m thrilled with this motor.
Second, you need a deep cycle 12v battery, meant for deep discharges (not the same as the battery that starts your car). Here’s where things get tricky. My kayak is pretty big and can hold a lot of gear and weight. However, batteries can be really heavy. The tradeoff is run time vs weight. I settled on a relatively small 35 amp-hour battery; at my motor’s medium speed (~3mph), it’ll run for 2-3 hours and take me at least 6 miles. It weighs 23 pounds. I still wonder whether I should’ve gone with a 55 amp-hour battery, which would last about twice as long but would weigh almost 40 pounds. I’m more or less stuck with the smaller battery now, so I went ahead and bought a second one to take on longer trips.
Third, you need some other stuff related to the electronics. A water-resistant battery case and a battery charger are must-haves. And because connecting the motor to the battery while inside the kayak is a pain, I also rigged up a quick-disconnect system, which required some extra 8 gauge wire (I could’ve gone with 10AWG and been fine), ring terminals, heat shrink, and quick disconnect hardware.
Fourth, you need a way to mount the motor to the kayak. I’m getting to this soon, I promise.
Fifth and finally, at least in North Carolina, you need a vehicle registration from the Wildlife Resources Commission, just like you would for any other boat.
The total expense for everything was a bit north of $400 (more than I paid for the boat).
Okay, on to the custom motor mount. The trolling motor (like essentially all others) is meant to be transom mounted to the back of a boat by clamping it to a flat surface. For my setup, that meant creating a flat, vertical surface that would hang off the side of my boat, to which the motor would clamp. The trick was securely attaching this flat surface to my boat. To be secure and stable, I had to design a mount that would have multiple attachment points and would contact my boat across the entire deck. You can buy or easily make such a mount for flat-decked fishing kayaks. But as I mentioned before, my sit-inside kayak has a curved deck, so a standard setup wouldn’t work.
I decided to build a two-part mount made of cypress (rot resistant and stronger than cedar) and galvanized EMT conduit (rust resistant and easily replaceable). The first piece is more or less permanently attached to my boat and serves as the anchor for a removable second piece, which is larger and holds the motor. First piece = rail; second piece = motor mount.
For the rail, I used a cardboard template to trace the shape of my hull, transferred that to a scrap of plywood, cut it on the bandsaw, then refined the shape using a rasp. Once I had the shape just right (well, right enough), I cut the cypress, drilled some holes, and routed out a V-shaped channel at the top that would accept the EMT from the second piece. This rail is affixed to the boat in four places: two preexisting holes (used to secure stretchy webbing) and two new holes. Since the new holes are in the open cockpit area just behind my seat (and not the dry storage area farther back), they won’t have any impact on the boat’s performance. As you can see in the pictures, the rail is small and unobtrusive, and is effectively part of the boat.
I built the motor mount to mirror the shape of the rail, with the addition of the large vertical surface to which the motor will mount. This second piece is subject to two main forces: (1) gravity pulling the 25-lb motor downward, and (2) the propulsion of the motor pushing and twisting (racking) the mount forward. To evenly distribute the weight of the motor across the width of the boat, I used a piece of ½” galvanized metal EMT tubing, anchored on both the close and far side of the rail. The wood of the motor mount sits flush with and is bolted to the back and top of the rail, preventing racking from the motor’s propulsion. It’s a rock-solid setup, and looks pretty nice too.
It takes only a couple minutes to attach the motor mount to the rail with five stainless 1/4” bolts and wing nuts; I do that before getting in the water. Clamping the motor to the mount and connecting the battery takes another minute or two; I do that from inside the boat. Once I’m sitting in the boat, the weight of the motor doesn’t significantly affect the boat’s stability. I can cruise around for hours with a steady speed of 3 mph or a top speed of 4 mph. Or, I can rotate the motor up with a push of a button and paddle around just like I would without the motor, with a top speed of around 4 mph. Interestingly, paddling while the motor is running doesn’t seem to significantly increase my speed; I’ll see if this changes when going against a headwind or current. All in all, a great success and a lot of fun!