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Permalink Reply by Tom Hruby on June 2, 2012 at 12:27am

Troy,

I have not actually converted a motor boat.  What I have done is built a design that was meant for a gas engine and put in electric power right from the beginning.  I built my first one 16 years ago and have cruised here in Puget Sound every summer.  I am currently building my third St. Pierre Dory from plans provided by Glen-L Marine.  This boat is 26 ft so not quite as big as your 34' one, but I may be able answer some questions on how to figure out power requirements, prop size, and battery capacity.

Tom

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Permalink Reply by Braith Miller on June 2, 2012 at 2:57am

Yes would be the answer, though not personally. I have web seen many references to even planing hulls done as hybrid generator electric drive. That being said despite the benefits in doing so is not what you are likely after. I would stay in displacement hulls that are sleek classical in lines, double enders and the like. Pure electric is good for a 'plug-in' bay type launch, less than 50% discharge, full fuel tank weight convert to battery weight. Largest prop you can modify to run, 2x size(tug/heavy trawler style). The QE II is i think the largest hybrid on the Seas( no batteries just like all modern locomotives). Not enough info to build or install though I think it helps you start. The 34'+ that had a single small 4 cylinder is a perfect candidate with keel line access. Space for 144 volts / 72 cells, either singles or 6 volt( golf car) or 12 volt '8D's secured against capsize down keel line as required for intended use. One concept is take a ballast keel sail design, omit sails and ballast keel, batteries = ballast. Though I'd keep limited sail plan. Questions answered.

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Permalink Reply by Paul Artola on June 3, 2012 at 12:41am

Troy-

I have been thinking and researching this over the last couple of years. I am not a sailor, but like the idea of electric or hybrid propulsion, and am currently rebuilding a '75 Angler 20-footer for creek cruising with a Torqeedo outboard and small battery bank. This will be my intro to electric boating.

I have looked into the "next" phase for me - something like a trawler with more complex systems, but more comfort. Regennautic have refit a 42' GB, and that looks pretty cool to me, but I have yet to see in person. The Greenlines are sold and shown around here. They are really nice, but light years above my budget. Then there are the guys at IndependenceYachts. Some great ideas there, but only if I win MegaMillions! I talk to them at the local boat shows and try to get them to consider a 40-foot design, but they are still trying to get their 60-foot launched to keep the dream alive. Good luck to them.

One idea I have is to replace the diesel motor in a downeast or deadrise type boat with an electric, then get a fat battery bank, solar array, and a small backup generator. Optimally designed for daytrips and weekend cruising around the Chesapeake here.

My current powerboat is a 1988 Carver Santego30, a nice family cruiser, but with twin Merc 454s, it is a gas guzzler. However, with i/o drive, I was not encouraged to convert this until a YouTube video I saw yesterday, where some guys in Amsterdam have converted an old Glastron V174 (think Live And Let Die!). Sweet setup, but not cheap. However, they mated an electric motor to a Volvo sterndrive very nicely. Check them out (NewElecticPowerboat) on YT.

Right now, it seems to me Europeans are moving along briskly integrating electric propulsion in cruising powerboats, but battery technology and costs will have to improve a lot more before serious consideration comes to these shores. Still, I am hearing more and more about developments, so the future will bring better and better options.

- Paul Artola, Ellicott City, Maryland

 

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Permalink Reply by Sally M. Reuther on June 3, 2012 at 2:36am

Paul,

We have a 21' Ranger designed launch called a Martini 21 with a 5kW Thoosa in it. Great for traveling around Annapolis, and we have a small Honda 2000 we can use if we want to travel further than the 100 amp hour battery bank allows. 

The main issue with power boats is, of course, the speed issue and range. Trawlers are great candidates for re-power with electric. The top speed will be a bit less, but you can fit a fair amount of battery power in there, and with a good, efficient diesel generator you are more like that QEII. 

Solar helps, but it takes a lot of panels to be able to put back a significant amount of power into the batteries that are taken down in large amounts by the electric motor. A well designed re-power solution that uses all of these elements however is certainly a great option and one that is worth looking at. It will be more expensive up front to put it all together, but over time it more than pays for itself in less fuel cost, less maintenance costs, more time enjoying being on the water, and doing your part to help make the bay a cleaner, quieter environment. 

Just like the electric cars, the costs are higher because the numbers of units being built are not enough to bring the cost down. We, the U.S., are far behind Europe in adopting this technology. Denmark is converting all of their canal boats to electric and they are building a ferry that will transport small numbers of cars and about 60 people in and around the islands there. They plan to be using wind power exclusively in another 10 years or so. We should follow their plan.

Keep working on your plan to convert a larger boat - it can be done.

Sally

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