# Electric Propulsion.



## GufShoz (Dec 5, 2001)

During a tropical storm, saltwater got siphoned into my Yanmar 2GM and sat for about a month before I realized it. I tried to salvage the engine, but it was pretty much a basket-case. My wife and I went to the Annapolis sailboat show last October to take classes about diesel engines and we saw a few electric propulsion dealers. After much discussion, we decided to make the switch going with Electric Yachts. We weren't compelled to "go green" with our Hunter 29.5, but now it is an added benefit. I'm sure that electric conversion isn't for everyone, but we do most of our sailing by "coastal cruising" around the northern Gulf Coast and this fits our style perfectly.
I know that there are a lot of talk about electric motors on threads here; mostly to the negative. I'd be happy to answer any questions about our conversion and the benefits we've seen. Send a personal message and we may start a new thread.
Terry


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## GNU (Nov 26, 2011)

Hi Terry,
I've had a similar experience, but on a smaller scale. I replaced my light Mercury 2 stroke dinghy outboard motor with a Torqeedo 1003 motor.
I read a bunch of skeptical posts in the subject and a number if overly positive reviews and had a hard time figuring out if it was worth the more costly upgrade, compared to buying a new 4 stroke.

After having used it for a while I have to say I like it a lot.
The three primary reasons are:
1. It's super quiet. I can go ashore at any hour without annoying anyone.
2. You don't have to pull and pull and pull to start it. 
3. It separates into three parts so it's very easy to lift.

The only flaw I found so far is the price.


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## sailingbud (Nov 5, 2009)

Hi Terry,

I am interested in converting a boat I am rebuilding to electric. The boat is a Nantucket Clipper a 32' 7.5 ton yawl. The original diesel is a Sabb 10hp thumper. It is miserly on fuel but all owners of sister ships consider it way underpowered and typically repower with a modern 20-26hp like westerberke. I just returned from sailing on a sistership and while on a beam reach with all sails up in a light wind, she gently ran aground. We loosened sheets, started the diesel, shifted weight around, rocked over the rail and just as gently backed off the sand bar. The slightly embaressed captain looked at me and in reference to my idea about electric power said, "This is the reason for having extra power. You can not do that with your old engine or electric power."
How about that? If a boat is fitted with the proper prop and an electric motor that would rate with 20+hp diesels, would emergency power situations be an issue?

Walter


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## RXBOT (Sep 7, 2007)

If you have equal hp. and torque then it does not matter what the power is derived from gas,diesel,coal,nuclear or electric the power will be the same. Energy storage is another matter.


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## deckofficer (Feb 18, 2012)

You will do much better in the above scenario with electric. A diesel's torque comes on at 1600~1800 rpm for the small diesels we use, an electric will produce full rated torque at 0 rpm. A slow turning, deep pitched prop can be used on an electric that would stall an ICE when engaged. At slower rpms, slip is less, that is why large container ships turn their screws direct with no reduction. At full ahead sea speed, 108 rpms on a loaded container ship turning a 19' pitch prop might only have 7% slip. Speed at 108 rpm would be 108 X 19' = 2052 X 60 = 123120' / 6082 = 20.2 X .93 = 18.8 kt

Here I have been collecting links to electric and diesel-electric hybrid for sailboats.
Integration of systems

I have served aboard steam turbine, low and med speed diesel, and a small 32000 ton diesel-electric, all having characteristics unique to each.


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## stewfish (Apr 8, 2012)

I read about the Lagoon's STI system and that got me thinking. Electric drive for Lagoon catamarans

Here is a bunch of interesting questions. Please feel free to add anything you think I should consider. 
How much was your cost? 
What HP are you using for your 28' boat (same as before?) 
How many batteries? and what's your discharge time 
What speed do you get the most efficiency out of it vs time before you run out of power?
12v or 140 v like the Lagoon's
do you use a wind generator to recharge as you are on the move/sailing or solar, 110/220 at the dock? How much did the charging system cost
I wondering if I could use a bunch of Costco deep cycle marine batteries at $65 each x 12 = $780 vs thousands.

I live in FL and this is sounding pretty cool with all the sun we get.

The Lagoon article says 4-5 hrs on 12 batteries
i saw one post of 11k for just the engine


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