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Old 05-06-2016, 12:04   #31
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Re: Electric Conversion

Originally Posted by MidlifeCrisis View Post
These folks made an all electric cruising sailboat. They post in their videos and web page lots of detail of how they did it.
Thank you I will check out all of their videos.

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Old 05-06-2016, 12:28   #32
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Re: Electric Conversion

Originally Posted by HillbillyMatt View Post
Has anybody actually used two trolling motors or multiple electric motors at one time to push a sizable boat so we can put this to rest? What were the actual numbers? (knots, voltage, head winds, currents, battery discharge, capacity of battrey)

How did you feel about it? Are you sold? If you didn't like it...WHY? Real facts based on actual events that occurred pros and cons?

If nobody has done it I guess I will have to and let you know what happens. Either way I am buying and keeping two on board in case one breaks. it's only $400 total and free clean power from Jesus.

I'm going to build my own solar panels for christ sake. I have a garage full of tools and a healthy budget set aside to build this boat. I'm not too worried about the price.
Yup I tried it. Maximum speed increased by about .25kn power draw doubled.

But keep in mind this was an incredibly slippery light sailboat. Short of an actual canoe I don't think many boats will perform as well.


- If animals weren't meant to be eaten then they wouldn't be made of food.
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Old 07-06-2016, 16:43   #33
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Re: Electric Conversion

Originally Posted by HillbillyMatt View Post
lonelysoldier, thank you. I am often surrounded by nay sayers myself. lol.

I thought about converting all of the electrical bits of a golf carts to use in my boat. the only problem was the cost of a used golf cart is still way more than I want to spend and the motor may be too much power for a sailboat hull...but it would all be there.

I am serious, about the electric scooter motor. The diameter of a coffee can. Plenty of torque and my WindRider 16 is only 476 pounds with me aboard. The tides around Tybee Island GA are the only reason I'm thinking of it.

Still surrounded by anchors.
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Old 07-06-2016, 16:55   #34
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Re: Electric Conversion

Originally Posted by lonesoldier0408 View Post
I have an electric scooter, with a 36 volt motor and controls, that I plan to use for a boat motor, when not under sail. The scooter was second hand but ran. Good torque for around town but short battery life. Add this to a weed eater, lower section, and off I go with all the others in my head.🤔🤔🤔😁😁😁

Still surrounded by anchors.
What size motor? 36V bike/scooter motors come as anything from 350W to 1000W. So you are looking at roughly 0.5 to 1.5 HP.

(Golf cart motors are generally in the 8-10 HP range)
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Old 07-06-2016, 17:33   #35
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Re: Electric Conversion

Originally Posted by HillbillyMatt View Post
boat_alexandra, also thank you.

also, I have been toying with the idea of a sculling oar. my concerns are...
Don't be concerned. Build a sculling oar.

I have built two now, and have also an extra blade (because I found it in the forest and it was already nearly perfect because some people had cut the side of the tree to make planks, and the bit they left was curved on one side (trunk of tree) flat on the other, and tapered correctly as well...

1. I don't yet know how to build one but I have been amassing a workshop full of tools to be able to do such things.
I used only hand (not power tools)

Hammer and chisel and drill.

2. I don't understand how they work mechanically/hydro dynamically. I have watched one working in a video so I can see how they work, but I imagine its like building a boomerang and it looks easy but...(my boomerang did not come back. lol)
It is like a falling leaf. There are two possible styles, but the yuloh has the bottom curved and the top flat.
3. im not sure how I would mount one or where to get the special swiveling mount.
A large oar lock would be nice, but I used a trailer hitch (ball and socket)

4. im trying to trailer sail to avoid unnecessary slip fees so I need enough power to seat the boat on the trailer whilst maneuvering and possibly fighting currents. although I like the idea (and will most likely adapt it) to assist my first solo motor getting to the launch ramp or any other case when I cant be under wind power (like narrow ICW passages)
Why can't you just use a rope to pull the boat into the trailer?
5. I was a little confused by that last bit but I am assuming you meant to say that its really quite effortless to use one. lol
Yes, well it's the same effort as walking to move 1 knot.

Originally Posted by Stumble View Post

Just a few things...

1) one large bank will provide more usable power than two smaller ones. Battery output capacity drops as a function of how quickly you pull power out see Pukerts laws.

Don't break your batteries into separate banks, at least not with lead acid. With lithium you might consider it, but even then I would have unequal banks, with one as a small reserve or emergency.
2) the efficiency of trolling motors at all speeds is very high. Wether you use two smaller ones or one large one will have minimal effect on power needed to hit a particular speed. Is anything multiple small motors may negatively impact range because of the added drag of the multiple motors.
Typical efficiency of electric energy to thrust of a trolling motor is 25% at best. Of course if you use a slower propeller and gears you can reach 50% or better (up to 85% in some experiments). Solar panels are around 15% (or maybe a little higher for premium ones) so overall you are lucky to get 4% from sun to thrust.

gas outboard is below 5% efficient at fuel to thrust. The fuel itself is well below 1% from sunlight to crude oil, and the refinery is less than 50% efficient, and transporting the fuel uses a lot of fuel... so you are looking at something less than 1/100th of 1% efficiency. Solar electric is more than 300 times more efficient. You could travel 300 miles and consume less energy than someone with a gas outboard is going just 1 mile.

The sculling oar itself is around 80% efficient but the human body is at best 25%, and producing the food is below 1% (unless you eat only sugarcane) so overall 1/5th of 1% at best. This method only requires some pieces of carved wood though so it by far is the least energy to install. It also by far the most reliable and easiest to repair etc...

3) a range of six hours is meaningless. You need to know the range in miles, preferably miles and time. You maximum range will be somewhere in the 20 hour range, but you would need to slow down to .5kn or so to get there.
Consider I could go 2 knots using only 12 amps and 12 volts, I would never need to slow to .5 kn.

20 hours is ridiculous because except in very rare cases where you can just wait anyway, you will always get either wind or sun in less than this amount of time.

4) seriously invest in a small gas generator. This will have more effect on range than anything else you could do.
If you care nothing about efficiency and like to waste energy while also making obnoxious noise pollution, then yes.

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