The goal of this project was to convert a gas-powered trolling motor into an electric powered one within a night.
- Lathe and Mill
This project was a collaboration effort between Dane [Website] and Myself, the goal was to convert a gas power trolling motor into an electric trolling motor. The main motivation for this was to allow us to use it on a lake that had restrictions on gas-powered craft, but no restrictions on electric. The main reason for this is the lake used to be an active reservoir, so many restrictions are still in-place to keep its clean.
Initially we tested the motor out on a loading dock, it still ran but was an insanely loud two stroke motor outside of the water. Interestingly enough the original design used the water as a muffler. One of the MITERS members (Fred) decided to keep the motor once we had removed it.
After removing the old two stroke motor we examined the mating surface that couples the shaft to the motor. We did some quick rough CAD in order to create a new mating shaft and motor mount assembly. The new mating shafts purpose was to mate the electric motors shaft with that of the propellers shaft, it was important to have a tight mate between these shafts with limited slop.
Dane Took on the job of finalizing the mating plates we would use to make the motor directly to the shaft housing, This was ultimately done using a waterjet on some thick aluminium scrap plate. But some post-waterjet machining and bearing press fitting was required.
I took on the job of machining the Steel shaft couple, and then fabricating a Tiller. For the steel shaft couple, I mainly focused on turning the piece into the proper diameter and shape to properly fit into the holes we had designed and had to work with (Motor shaft hole & propeller shaft couple). The more difficult part of this fabrication laid in the milling out a tight fitting mating surface that would mate with the propeller shaft. First I drilled out a center hole on the end of the shaft coupler to the designed depth. This hole is important because the design of the propeller shaft is a cylindrical shaft with a steel pin mounted in a perpendicular direction, creating a cross shape †. Since we are creating this shaft coupler out of steel, the slot we milled had to be done in small increments as to not damage the small end mill. Once machined, I sanded down some of the sharp edges and moved onto the tiller.
The motor was not designed for a tiller, but there were some tapped mounting holes on the sides of this motor in vertical pairs of two. This was fortunate, so I took a simple piece of angled steel and cut it down to size so that this bracket could fit both bolts. Unfortunately I had to dig through the imfamous Crypt of Various Screws in MITERS to find two identical sized bolts for these holes. Once found, I drilled out two holes in this bracket and deburred them. Next I took a steel tube and estimated the necessary length and cut it on the horizontal band saw. Next I stand down the end and some of the mating surfaces on both the tube and the bracket, as to prep the surface for welding. And then I welded the two pieces together. Next I wanted to figure out a way to add a grip to the tiller arm, luckily enough I found a bike handle bar grip in our misc. bike parts drawer, and on top of that, the steel tube I had chosen was just the right diameter to fit this handle bar grip. Finally we wiped down the piece and did a basic orange spray paint coat out on the loading dock. This took awhile to dry, so we ended up testing the motor without a tiller in a home depot bucket full of water… with a professionally designed lid… 🙂
Ultimately we ended up finishing the construction in a single night/morning, and headed out to the lake in question. It was still the tail end of winter ~May when we first tested out the motor, so everyone was wrapped up tight. We did a few solo tests around the dock before we did an all hands on deck (Myself, Dane, and Ciaran) trip out to the island on the lake. Once we had made it, I broke out a little foldable steel fire box and made us some victory tea. Overall a successful weekend project 🙂