With sailing season now beginning, it was time to put the new electric motor to the test in the real world. To finish up the basic preparations, I purchased a small tractor-sized deep-cycle battery rated at 45 amp-hours–the largest one that would fit in my plastic control/battery box, and with the highest rating I could find. The battery came without terminal screws, and it took some trial and error before I determined they were M6 thread. What I really needed were cap screws, but for the moment I settled on what I could find locally, which worked fine but didn’t give much of a purchase for battery charging cables, which I expected to need frequently to keep the battery at full capacity.
The white hose I’d selected as a conduit for the motor wiring off the rudder was a bad choice (I don’t know why I think that white sanitation hose is ever satisfactory for any use), and turned out to be too inflexible to work as I’d hoped. Instead of providing a clean, minimally-invasive wire conduit, the stiff hose, which retained a memory of its being coiled too tightly when I ordered it from the supplier, was bulky and awful, and would not be tenable for long. For now, it’s what I had, but I planned to replace it as soon as I could.
Once I launched and rigged the boat, I took her out on a calm day for a real trial. I was really pleased with how well the little motor worked. There was ample power, and I found that once I got the boat moving in whatever direction using one of the higher speeds (4 or 5 out of 5), I could turn the speed well down and the boat still moved well. This should reduce battery drain, I hoped. With no experience with trolling motors, I really didn’t know what to expect in terms of battery usage, though I knew the battery I’d selected was small–about half the capacity of even a basic car-sized starting battery.
Initially, I’d not had any markings on the control box to show which way to turn the knob, or where the graduations were. This was highly confusing during my launching, when I used the motor briefly to dock the boat. So I made some simple markings on the box, seen in the video below, and later (post-video) I used some white paint to make a tick mark on the knob itself to help register it in whatever position. It wasn’t easy to take video in a way to give much of a sense of things, and I didn’t want to create one of those awful shaky videos that would have happened if I’d tried to manipulate the controls, or somehow get better angles, so this short video is what you get for now.
The worst-case scenario is that I end up needing a larger battery, which I’d then have to install somewhere at the aft end of the cockpit, and which might be less convenient overall. I liked the idea of the control box/battery compartment all in one like I’d conceived it, so I hoped it would work. Further testing in real use will determine whether the battery has the capacity I need. Normal usage will include departing the dock and getting out a narrow channel, probably about 5 minutes’ use at the onset, and then the same thing on the way in. (This all assumes that, as experience seems to have shown, I will be unable to easily sail in either direction.) No harm will come if the battery dies before I’m ready, but it’ll just be inconvenient. The water is mostly shallow, and worst-case is that I point the boat to the nearest shore and walk her home from there. I shan’t be miles from home ever in this boat anyway.
Further updates later as things settle out. The season is just (barely) starting.
I finished up the project by creating a long wiring harness between the rudder’s wiring and the portable control box. Judging how much slack I’d need to comfortably run between the rudder and the boat’s cockpit when things were rigged, I ran a four-wire harness comprised of the same color wires as the motor’s originals through some 1-1/8″ hose, which would fit over the end of the rudder’s conduit. At the boat/control box end, I connected the wires to the four terminals of the large plug assembly, matching up the wires and terminals to the receptacle end that I’d already installed in my portable control box.
When I went to test the fit of the plug in the receptacle, I was dismayed to find that the plug wouldn’t stay in place. This puzzled me for a little while, till I determined that I’d reassembled it incorrectly. The rubber insert, which contained the terminal studs, featured a little bead around its perimeter, and when I put it back together I’d assumed this bead should be right where the insert came out of the plastic housing. However, I learned that the bead was actually what held the plug in place inside the receptacle, so I dismantled the plug and reassembled it with more of the rubber insert protruding. Now the plug stayed in place nicely.
With that, I temporarily wired up a 12-volt battery and tested the motor. Success! Five forward speeds and three reverse. The large knob I’d chosen for the control worked well and was easy to change from setting to setting. I have three different (yet similar) videos showing the operation and since I couldn’t decide which was best, I just uploaded them all. Enjoy one, all, or none.
With that, the project was complete. I couldn’t wait for a real test on the water! But that would have to wait a few months.
The switch, or controller, that I removed from the original electric motor housing was all that was needed to control the motor (located in the propeller hub) itself. My goal in this installation was to create a simple and portable means of transporting and connecting the controller switch and 12-volt battery to the wiring from the rudder, so that I could quickly install and remove the controls whenever I used the boat, and keep the battery charged up ashore in the meantime.
To this end, I hoped that a small 12-volt battery (such as the small case size often seen in lawn tractors) would provide sufficient amp-hourage for my limited motor use. Obviously a smaller battery would limit the length of time I could run the motor, but I thought my needs were minimal enough that the desire for easy portability would take precedence. The instructions that came with the motor recommended a minimum 105 amp-hour battery, which made sense for all that, but I thought/hoped I wouldn’t need such capacity since I only planned to run the motor for perhaps (thinking generously) 10 minutes total per trip.
With this in mind, I found a plastic toolbox (ostensibly “waterproof” with a gasketed cover, though this wasn’t a criterion for me in this case, nor had I any illusions about the sanctity of the lid seal) that was large enough to hold a standard lawn tractor battery, and I planned this box to form the basis of my controller installation. For illustration, I used a tractor battery I had on hand. Truth be told, I’d purchased the box thinking it would also be large enough to hold a group 24 size battery if needed, as the listed dimensions suggested this, but of course the inside of the box was somewhat smaller and too tight in height and width for a regular battery.
These little batteries weren’t, in the main, rated by amp hourage, as they weren’t deep cycle and, as small engine starting batteries, were rated only in cold cranking amps. Some online research revealed low amp-hour ratings (in the 18-20 amp-hour range) for these batteries from other sources, but after additional searching I located a deep cycle version rated at 45 amp-hours in a similar case size that would still fit in my controller box. My plan, once I purchased the exact battery, was to build some internal bracing to hold the battery in place at one end of the box, leaving the other end open for the wiring and controller.
Satisfied that the box idea would work for now–only time in actual use would determine whether the small battery was enough for what I needed–I prepared to install the controller switch in the end wall of the box. I drilled a hole that fit the diameter of the housing around the control shaft, and cut by hand a small slot at the top to match the molded keyway on the switch housing. This allowed me to insert the switch from inside the box, with the control shaft outside. To hold the switch in place, in addition to the friction-fit cutout and keyway, I applied some epoxy after I scuffed up the plastic on the box. I hoped this would be sufficient for the basically light-duty use the switch would experience. I braced this in place while the epoxy cured.
Outside the box, I used one of the plastic pieces that originally came with the motor, and which slipped right over the metal control shaft. This piece originally allowed connection of the tiller-type control handle, but I didn’t plan to use that. Instead, I found and ordered a knob for outside that would fit over the roughly 1/2″ diameter of the shaft cover. As of this writing I awaited delivery of the knob.
To cover the wiring connections and back side of the control switch, I purchased a plastic storage tray that I could hang over the switch, covering it completely from inside while allowing wiring to pass below the cover. As a simple means of installation, I epoxied in a wooden cleat above the switch, which, once cured, would allow the cover to hang over the switch for protection. I’d use a single screw to secure the cover to the cleat.
For ease of connection and disconnection and transport of the battery/controller box, I ordered a plug and receptacle for the wiring between the box and the rudder. Once the matched set–though sold separately–arrived, I set to work to install the receptacle and wire it to the controller switch. The plug and receptacle were large and fairly serious duty, perhaps more than the job called for, but this was one of the only 4-wire setups I’d found; I had four wires to connect. In any event, it looked like it would more than hold up to the continuous connection and disconnection that I had in mind, so good enough.
I cut a hole in my portable control box, then installed short lengths of wire–in the same colors as the motor’s original wiring–to the four terminals, choosing them arbitrarily since it didn’t matter. Then, with the receptacle installed in the box (I used small machine screws and nuts to help hold the receptacle against the pulling motion of plug disconnection), I connected the four short wires to their respective terminals on the control switch.
I finished up the box-end wiring with a 50-amp circuit breaker that I installed in the battery positive line. I protected the exposed terminals with some heat shrink tubing, just to prevent the unlikely event of a short across these terminals in the generally unprotected environment within the box. Then, I installed my simple wiring cover over the works of the switches.
To finish up the control box, I installed a large knob on the outside of the controller. This fit over the plastic piece leftover from the original motor configuration, and I secured it with an included setscrew. Later, once I tested operation, I’d make some tick marks on the knob and on the box to indicate the motor speed and direction.
Meanwhile, over several different days, I applied two additional coats of semi-gloss white enamel to the rudder, completing the paint work. Once that was sufficiently cured, I masked off and painted the lower portion of the rudder with new bottom paint. All that remained for this project was to finish up the rudder-end wiring, including running the new flexible conduit (aka hose) and installing the plug at the end; I planned to complete this soon, and effect a bench test of the whole system shortly thereafter.
Total time on this job today: 2.75 hours (spread over several days)
Continuing the project in short bursts over several different days, I kept up the work on the rudder, starting with sanding the fresh fiberglass to smooth and begin to fair it in with the surrounding surfaces.
The new fiberglass was mainly smooth and flush with the adjacent surfaces, but to fill the cloth weave and take care of minor low spots, I applied a coat of epoxy fairing filler over the new work.
Later, once the filler had cured sufficiently, I sanded once more, bringing the new work nearly to its final contours.
After some final and minor filling on portions of the rudder, mainly around the edge where the vertical shaft now protruded, I continued work on the electrical side. To route the wires forward towards the boat, as well as provide protection and watertightness to the wire run, I added a PVC elbow and used the cutoff length of the original composite shaft to lead the conduit forward across the top of the rudder. I used a 3/4″ PVC elbow, which was a little small for the 1-1/8″ OD of the shaft, so with a heat gun I warmed it up so I could expand the openings as needed to fit the diameter of the pipe. Then, I glued on the elbow and the horizontal section of conduit with some 5-minute epoxy. I used a little wedge at the forward end to ensure that the angle of the pipe was where I wanted it while the glue cured; this would allow room to slide over a length of hose through which the wires could continue their run onto the boat where they’d eventually connect to the controls and battery. I’d need to be back at the boat (located remotely at the moment) in order to finalize the wire and flexible conduit lengths.
When the glue cured, I performed some final sanding on the new work and the pipe assembly, and also sanded the entire above-waterline portion of the rudder to prepare the original gelcoat for priming and paint along with the new work. After masking off the waterline and hardware as necessary, I brushed on two coats of epoxy-based primer to seal the fresh epoxy work and also provide a consistent base over the gelcoated forward areas, as well as the black wiring conduit.
When the primer cured overnight, and after a light sanding, I applied a first coat of gloss white paint.
I wasn’t happy with the first coat and it didn’t cure properly, so the next morning I removed it (it wiped off with paint thinner and minor effort), and started over with a coat of semi-gloss white enamel that I thought would better match the old gelcoat on the rest of the boat.
Total time billed on this job today: 3 hours (spread over 6 days)
Now that the propeller hub and vertical shaft were well tacked in place, I removed the wedges and tape and lightly sanded the epoxy from overnight, then cleaned the surfaces. With more thickened epoxy, I filled in remaining gaps around the pod and shaft, and smoothed in some fillets around various areas to streamline the shape for fiberglass.
Meanwhile, I prepared two layers of fiberglass for each side, one full size to match the shape of the ground areas and the second about an inch smaller all around to match the tapered edges of the patch area. Once wet out with epoxy, I installed the new fiberglass over the whole area, rolling it tightly into the contours of the shaft and hub. At the top and bottom of the propeller hub, and around the top of the vertical shaft, I added some light cloth to seal the edges completely.
A while back, I purchased a 14′ Handy Cat, built in 1973 by Cape Dory (this design, like many small boats, was licensed to a number of different builders over the years). The boat was in great shape from the onset, though the previous owner had had the poor judgement to install a horrendous outboard bracket on the delicate transom. The first thing I did once I bought the boat was remove this abomination, not only because I hated the looks, but also because I had no intention of using an outboard on this boat.
Where I sail (or attempt to sail) the boat is a shallow creek with a narrow entrance leading to an expansive (but still shallow) bay. What I quickly learned in practice was that it simply wasn’t realistic (or even possible) to sail out the entrance channel, which had a navigable channel only perhaps 10 or 12 feet wide, other than at the occasional (and always very early morning) extra high tide that filled the adjacent sand/mudbanks satisfactorily. This never occurred at any time when I actually felt like sailing: for whatever reason, the tide cycle here never seemed to allow these full tides during the middle part of the day or evening. That’s a whole discussion in and of itself; suffice it to say that the tides never acted favorably to provide more room in the channel.
The direction of the channel–which also curved significantly over its considerable length–rarely caused the winds to align in such a way as to make the entrance passable without a need to tack–which was, frankly, quite impossible given the narrowness. And when the wind direction seemed right, it was too snotty. A complicated situation to be sure, but for this seemingly whiny combination of reasons it never worked out well for me to get this little boat out into the real waters.
The long and the short of all this is that I found the channel to be an impenetrable barrier to fun and useful sailing, which not only limited my use of the boat, but even my interest in trying. I’d initially thought I might use oars to row the boat out the channel as needed: it came with oarlocks. But this turned out to be a non-starter, as the low boom and centerboard trunk prevented any sort of realistic rowing position, and any oars long enough to actually reach the water without an absurd angle would be impractical on board. So this turned out to be a failed idea as well.
After a full season filled with disappointment and guilt over the situation, I determined that to have a chance at sailing this boat in a satisfying way, I’d have no choice but to provide some sort of auxiliary propulsion for the channel. There was a more traditional outboard bracket available that wouldn’t look so terrible, but I still hated to go that route for various reasons: the weight and appearance of the outboard; the need to buy a new outboard; my general dislike and dissatisfaction with small outboards to begin with.
Then, a friend told me about an interesting installation he’d seen on a newly-built Eric Dow Boatshop Herreshoff 12-1/2, where they’d built a custom rudder that incorporated an electric-powered propeller and shaft within. While the 12-1/2 is a very different boat, I thought the idea was terrific and might solve my problem.
Image from Eric Dow Boatshop
The Handy Cat, like most or all traditional Cape Cod catboats, features a large, shallow barn-door rudder hung from the transom. The rudder seemed to offer plenty of space to incorporate a small propeller and housing. For my specific needs and location, I didn’t think I required much in the way of power, and therefore the propeller size–and size and shape of the housing–wouldn’t overwhelm the shallow rudder.
I spent some time researching trolling motors, about which I really knew nothing and with which I had no experience. (My only foray into fishing was many years ago, all saltwater and on larger boats, and at which I was an utter failure.) Soon, the project began to come together in my mind, and I settled on a small, inexpensive Minn Kota Endura C2 30 transom-mount trolling motor with 30 pounds of thrust. The motor had 5 forward speeds and three reverse. The usual Internet scuttlebutt suggested this was a competent motor, well-rated and well-liked by its users, and with ample power for what I needed, which frankly was 5 minutes’ use per time to proceed through protected waters in a small, easily-driven boat. The low entry price really gave me nothing to lose, which was good since I’d need to dismantle the motor for my installation. The fact that the engine was built for freshwater was of little matter to me, as I felt it would hold up in my limited season, and anecdotal reports online suggested similarly. My final installation of the electrical side would actually end up more durable than the original, so that didn’t concern me either.
I found some useful videos online detailing some of the basics of disassembly, and it looked much simpler than I’d even imagined (again, I’d no experience at all with these little trolling motors and didn’t even know how they were put together). To that end, I’ve chosen below to detail thoroughly my own disassembly for the edification of anyone else looking to do something similar.
When my new trolling motor arrived, I wasted no time disassembling it, though I began with thorough documentation of the motor in its original form. The electric motor itself is housed within the propeller pod, with only wiring and the controller switch in the housing above. The adjustable transom mount would slide right off the shaft once I took apart the top housing.
The housing featured a clamping screw to hold it to the top of the vertical shaft (which was a composite, not metal, construction on this motor), and six screws beneath that held the two plastic parts of the housing together, and this took little time to take apart.
The wiring from the propulsion pod led up through the vertical shaft and connected to the internal control switch (all the terminals were labeled with wire colors for future reference), and the battery wires led out through the bottom of the cowling. The various wires were secured with built-in plastic clips within the compartment as needed, and the control switch itself was held in place with a little plastic spring clip, and was easy to remove. Once I had the switch out, I removed all the wires, which freed the switch from the housing. I’d need this switch for controlling the motor later. The tiller/twist control handle slipped right on and off the shaft of the rotary switch. What this all left me with was the bare propeller housing and vertical shaft, with its internal wires running out the top, plus the switch and battery cables that I’d need later. For my installation, I had no need for the transom bracket.
With the rudder on my bench, and the now-bare propeller hub, I tried out some layout. The instructions recommended minimum 12″ depth from the waterline to the top of the propeller pod, but I didn’t have that much space here, so I compromised with the pod at what looked like a reasonable depth, taking into account the shape of the rudder and how best to incorporate the pod within. I wanted to minimally impact the function of the rudder while keeping the installation as sleek and unnoticeable as possible. Once I was satisfied, I traced the outline of the pod and the shaft.
The composite shaft was longer than it needed to be for my installation, so I marked it at the appropriate height (about even with the straight top of the rudder) and cut off the excess tubing, using a smaller tube inserted within to protect the wires during the cut. I hung the shaft upside down from a vice so that any cutting spoils would drop out the tube rather than fall possibly into the propulsion pod. The tube was easy, if awkward, to cut in this position and given how my vice happened to be set up.
For the moment, my focus was on the rudder modifications, so additional steps to deal with the wiring and controls will come later. Now, with the wiring tube cut to length, I turned to the pod itself, which was constructed from aluminum (with a plastic propeller) and featured the usual trim tab/skeglet beneath the pod. I didn’t need nor want this for my built-in installation, so I cut off the skeg with a grinder and cutoff wheel. This skeg was surprisingly robust and took a minute or two to carefully cut away.
With layout finalized, I made two cuts in the rudder: first to remove the small piece outboard of the vertical shaft (I’d reuse this piece to reconstruct the rudder); then the other line I’d traced, removing the material in way of the new motor unit and shaft. The rudder on this boat was constructed with a solid mish-mash material between the two skins, so cutting with a carbide blade was not difficult and the rudder itself required no extra work to prepare the cutout area afterwards.
I dry fit the components now that the cut was complete.
To prepare the rudder for reassembly, I ground off the paint and gelcoat on both sides of the cut, tapering back the original laminate about 2″ all around. I prepared the pod and shaft by scuffing up the bonding surfaces with sandpaper as well.
Clamping the rudder vertically in a vice, I temporarily secured the pod with some wedges beneath and some tape above, centering it carefully on the rudder. Happy with the position, I dabbed in some hot glue top and bottom to hold it securely enough, and used some additional glue to tack on the small aft piece of the rudder in its proper position.
Meanwhile, I prepared some thickened epoxy to tack the assembly in place, enough to hold it securely once cured, but with some obstructions in place for now I left some areas unfilled; I’d take care of those later. I left the glueup to cure overnight.
