How to convert your sailboat from gas/diesel to electric

Sailing is a beautiful way to travel. It is fast, quiet, and fun. If you are like me there is a great feeling when you are able to turn off the motor (which is typically very noisy) and start sailing. Naturally the idea of a quiet motor that doesn't need to be filled up with fuel would be appealing to any sailor, at least in our dreams. So, does the option of a switch to an electric motor offer this dream up as reality?

First, let me explain that at first blush you might ask why even consider this option since I could find no other example of anyone in this area doing something like making a switch to electric motor for their sailboat? Surely, if it was such a reasonable idea somebody else would be doing it. Secondly, if there are no others doing it then surely it must not be a very good idea? And yet, it may be the case that nobody has tried it because the answer to the first question has prevented anyone feeling comfortable enough to move forward to try it to verify whether it is a good idea or not.



In my own case I've been using renewable energy (solar PV and wind turbines) to generate electricity at my house for the past ten years. In fact, we have no furnace, no gas/oil bill, and only use renewable energy sources for all our needs in the house (for all the details see http://www.naturallifenetwork.com/wilson.cfm). So, given my own personal experience, achieving this objective with our forty year old 35 foot C&C sailboat seemed like a reasonable possibility.

With a few mouse clicks and a google search I found Electric Yacht (http://www.electricyacht.com/).  After reviewing a few of their conversion stories and youtube web videos I was convinced we could make this work on our boat. In addition, since our forty year old Atomic 4 gasoline engine was in need of some expensive repairs and a steep learning curve for us novice sailors, the switch to electric would make the task of managing the maintenance and up-keep of the motor much easier. Of course, it has always been clear that there would be limitations in switching to electric. The battery system and their cost would be limiting factor on how far we would be able to travel using the motor. I could see very little chance that it would match the distance a full tank of gas would allow. However, I also understood that 90% of the time we would be using the motor primarily to get on and off the dock. Still, in an emergency and during longer passages we'd need to be sure we understood the limitations of the batteries ability to deliver power, for instance in a storm. Also, the question of sufficient power was also a concern, although the choice of electric motor (larger or smaller) could largely alleviate this concern...although with the connection that a larger motor, drawing more power, would affect run time limitations with the battery.

Working to determine the best solution for our boat we came up with the selection of a 10 kW (roughly 17 hp) electric motor as a reasonable replacement for the Atomic 4 for our particular needs. Of course we could have selected the 20 kW motor for additional power. For batteries, we ended up selecting four high quality Odyssey AGM deep cycle batteries. Although lithium ion batteries are an option that may provide substantially more storage and far less weight, their cost is currently two to three times that of AGM. As electric cars enter the mainstream we can expect the lithium batteries to become the cost, weight, and storage option of choice.

A few things that make electric motors more interesting than you might think for longer journeys with a sailboat. While underway sailing a fixed prop will turn the electric motor making it a generator that will charge your batteries while you sail from port to port. In addition, as in our case, by adding some solar panels (and wind turbine), as well as a backup biodiesel generator, it is quite easy to create a system with run times the equivalent, if not superior, to pure gas/diesel options.

So, then, how much does it cost? Well,  our 10 kW brushless electric motor kit (includes controller, throttle, motor, and mounting brackets) from Electric Yacht was US$4,995 plus shipping (from the US). The 4 large Odyssey 1800 rack mountable AGM batteries were about  CAN$3,300. An Analytics charge controller was about CAN$2,200. Finally, the installation, done by Lorne Spence from Genco was approximately $3,400 (roughly 40 hours). So, it certainly is more than a new gas or diesel engine. However, we have essentially zero fuel costs for the life the motor and we expect fewer maintenance costs as electrics tend to be very reliable.

As for how the system performs in the real world...for that you'll have to read earlier blog entries and keep an eye out for future updates. In a word...the system works beautifully. She is quiet, powerful, and has enough run time and then some for all of our needs thus far (trips across Toronto Harbour and back, and we think enough to do a couple hours at 3-4 knots). Hope this helps get you thinking about an electric as viable alternative if you are thinking of replacing your aging gas/diesel engine on your sailboat. If you have question I'd be happy to try to answer them. Just send me a note at wilsonjd9@hotmail.com.



For a fellow sailors view of the experience with our electric powered sailboat check out his excellent blog: Ian Hoar - Wind and Sail.