22'6" Fiberglass Keelboat, Built in 1965 Restored 2009-2017 by Colin Davis New Orleans, LA
Scroll down for the story and pics of hull restoration (below Outboard story).
Electric Conversion of Outboard
February-July 2020
I converted a 1955 Johnson CD-11 5.5 HP outboard to be electric. These motors were very popular and lots of service parts are still available from enthusiasts who salvage and maintain them. I didn’t know that when I got started, but it turned out to be a fortunate stroke of luck that I chose this motor, as it was easy to find info on how to disassemble, get new seals, OEM-color paint, decals, etc).
After the electrification was done, I also completely disassembled the motor, media blasted all the parts and repainted and re-assembled (and applied new decals). Unnecessary, but hey... the whole project was unnecessary!
I installed a Kunray 2000W 48V, 45A brushlesselectric motor, and I paired it with a Btr 48V, 20 Ah (~960 Wh) LiFePO4 battery (battery in an external case, not inside the motor cowling).
With about a year of testing, I've found that I get about 90min of run-time at ~2 kts. Full-speed is about 4.0kts, and I only get about 30 minutes of run time at that speed. I believe I'm not really using the motor to it's full potential because the propeller is still original, and is not an optimal profile for an electric motor. I only use the motor for trolling in and out of the harbor (maybe 10-15 minutes each direction, at 2-3 knots, so this battery is sufficient for now.
I take the battery off the boat and bring it home to charge. It's easy to carry around. I have considered solar charging, but.. that's another project for another day!
The motor kit was ~$200, the battery was ~$420. Adding up all the other expenses (battery case, battery gauge, wiring, fuses, connectors, paint, decals, etc.) would likely add another $600. That doesn’t include random bracket parts I scavenged, and 3D printed parts I made. And the salvage original motor was $100. All together, still cheaper than a Torqeedo or ePropulsion (excluding my not insignificant amount of labor)!
The motor and battery were both via Amazon and designed for electric scooters or bikes. The motor came as a kit that included the motor controller and a motorcycle-style twist throttle with a small built-in battery gauge. I didn’t use most of the twist throttle or battery gauge (the above gauge was bought separately), but I did salvage one component from the twist throttle - a curved 'arc segment’ magnet, magnetized along it's circumference). This was used in the throttle along with a tiny magnetic hall sensor, that senses change in magnetic field as the throttle rotates. I re-used it the same way in a custom thumb wheel throttle I installed in the tiller, along with a small button that can switch between ‘forward’ and ‘reverse’.
I also used this project as an excuse to learn a new 3D CAD program called Shapr that runs on an iPad Pro and is controlled with an Apple Pencil. I use a few different high-powered CAD programs regularly at work, and was curious what could be done on an iPad these days. It's amazing what is now possible on an iPad, but it's still early days for 'tablet-based' CAD. Things are progressing rapidly, though. Since I did this work, new iPads can do 3D-scanning of geometry into a CAD program like Shapr - that would have been very helpful here, and might have saved me much caliper measuring and test fitting!
Below are a few more of the many pictures I took. As a side note - in order to make this feasible, I also had to change out my motor mount to an articulating version that swings down. This motor is a 'regular shaft' (not 'long shaft'), and it needed to go down a few more inches to get the propeller decently submerged.
I’m happy to answer questions if something is unclear. Just contact me at ‘colin.a.davis AT outlook.com’
I have 2.5hp Suzuki that is great. Reliable, plenty of power, etc. But it’s loud! I hate cranking it up after a sail. All that peace and quiet - shattered. So I started thinking about an electric outboard. Torqeedo makes several nice, but pricey options. There are other cheaper options now (e.g., ePropulsion), too. And I thought about a trolling motor, but I don't believe that would be enough power to move safely in windy/choppy conditions. When not sailing, I’m a Mechanical Engineer who does new product design. So I figured, what the heck, I would just make one!
I considered building from scratch, thought about putting a motor ‘in the water’, vs out of it (up above), and attended a local seminar on building electric bicycles. In the end, I figured it would be simplest to convert an existing gas motor.
I found a local boat sales/repair shop that has a ‘junkyard’ of old outboards. I saw plenty of nondescript 80’s/90’s/00’s Japanese brands that were ‘fine’, but uninspiring, but I also saw a beautiful vintage Johnson - with fins! I didn’t know if I could make it work, but for $100, it was worth a shot!
In the process of this, I have learned two things - 1) we really don't make things like they used to (and this is coming from someone who designs products for a living!) This 65 yr old Johnson was in great shape and so easy to work on! Makes me ashamed of some of the things that ship today. Sigh. and 2) electric boats are very old news. The first electric outboard was invented in 1881! Electric boating has been pretty huge in Europe for decades (they are great on on nice calm lakes and canals!) But they still aren’t very common in the U.S., and especially not in Louisiana. This has been a ton of fun and I expect to get great use out of the motor, and I have learned a huge amount that I hope I can use in the future with other endeavors.
Launched Father's Day 2017 - In the marina at South Shore Harbor!
The Beginning... February 1, 2009
Purchase day! Traveling across Lake Ponchartrain, from Covington to New Orleans,
Safely installed in the back yard
March 2009
Many years of neglect had left 748 a wreck. Rain water had accumulated and sat, rotting the bulkheads and cabin benches. The previous owner had rescued her as an abandoned derelict in the marina, and had started repairs (removing and sanding cockpit benches, and painting hull above waterline), but... it had become apparent that the scope of work was more that he was prepared to handle. I was just young enough and dumb enough to think it would be fun..! Ah, who am I kidding... it's been a ton of fun!
Bit by bit.. cabin benches assembled and filled with foam. Main bulkheads installed.
March 2016 - Boat Sabbatical!
In March 2016, I decided it was time to get serious. I took a month off work and spent all my time tackling the biggest remaining tasks. In other word.. sanding, and patching, and sanding, and patching, and priming, and sanding, and patching, and more damn sanding, and finally... painting!
Painting done, benches varnished (Cetol, actually), some trim reinstalled, new chainplates and portlights installed, rub-rail installed.
After a productive few months, other responsibilities got in the way. But we have a nice new master bathroom! So.. there's that.
February 2017
Another big remaining task - the mast and boom. I would eventually remove all the hardware from mast and boom, and sand them clean. I originally thought maybe a light sanding would work. Nope. Had to go down to 80 grit paper on orbital sander to get 50 years of oxidation off. Progressively brought up to 600 grit wet sanding, then waxed. Took all the stays and halyards to local rigger and had all new rigging made.
March 2017
Recreating the doors, and figuring out how to mount cleats near the winches.
Finished installing brightwork trim, re-stalled bilge pump, with battery and solar charger. With the mast up, was able to finish installing running rigging. For finishing touches, placed a pinstripe along with the registration numbers and name!