Hello,
Please say a prayer. My wife and I bought a Compac 27 back in 2010 and life just changed and she has been in storage since then. We convinced the guys at Hutchins to install a SolidNav motor with 4 group 31 lifeline batteries.
I didn't think of the current draw of the meters and the batteries drained once, but I was able to recharge and have kept them disconnected and charged since.
If all goes well we will be raising the mast on May 22 and launching May 24 on Stockton Lake in Missouri.
Weather.com is already predicting storms on May 20, but I need to go anyway to have time to prep the mast and assemble the roller furling.
Hopefully, I'll have some good pictures and a boring story to tell when I get back.
Richard in MO
Compac 27 "Of Beren and Luthien"
Good luck to you! That really sounds neat, definitely need pictures of that setup
Mac
Very cool, I hope it works out well. I've been thinking often about electric propulsion. let us know how it goes!
Just nosing around on the web about this, SolidNav motor with 4 group 31 lifeline batteries. I read...
"Sunday, June 27, 2010 [Electric Boats] Re: 30 foot sailboat
Torqeedo Cruise 4.0R - 40 lb, $3700
[4] Lifeline AGM GPL-31 [70 lb, $270 each] - 280 lb, $1080 total for batteries. [I ask how many square foot for batteries = 2.5 sqft. or 112 lb per square foot.]
You get to figure out the bracket and placement of the batteries...
In electricboats@yahoogroups.com, javatogo3 wrote:
"Interested in adding a back up engine with a bracket with a output of 10 HP."
So 320 lb set-up of motor + battery = a 10 hp propulsion unit for for $4,780.00.
I'm thinking electric auxiliary power is not 'there' yet for the masses. We'll see.
hp = 10 [of course full bore, 10 hp running is limited]
Watts = 7,457,000
kW = 7.457
Btu/minute = 42,400
Btu/hr = 25,440,000 [180,000 btu / gallon of gasoline or 14.13 gallons of gas.]
Ft/lb /hr = 55,000 [0.30 gallons / minute]
Caution: ANY short circuit will arc clean through or explode within the hull.
skip.
This is WAY cool and I am hot to hear how it works out. My 1988 27 with the original Universal 10hp is a candidate for repowerng at some point in the next few years and I like everything I hear about electric (especially the quiet, the lack of diesel fumes, and the reliability). PLEASE update us the instant you take her out. Inquiring minds want to know!
Wes
When the conversion was done what kind of prop was put on the boat? Electric motors have so much instant torque Id really be curiuos to see her performance. Id like to know the amp hours consumed while at cruising speed.
Koinonia; Yes we have instant torque.
What's 'Instant Torque' have to do with anything on a prop in the water? I don't understand that statement. [On the ground that instant torque would just burn rubber until the vehicle gets moving] That 'instant' business only applies if the motor control is an 'OFF' ~ 'ON' controlled. 'Off' being zero hp. 'On' being 10 hp/full torque/full load amps. [Capacitor starting].
The prop at 10 hp and with no boat speed is just going to caveat [slip] until the hull comes up to speed.
If the electric motor is controlled by a rheostat, than lets assume the rheostat is at a ZERO setting to start with, and then with throttle up, well that's no difference then a gas engine throttling up and driving a prop.
With the rheostat advanced 100%, and the prop turning at top motor/reduction speed, the full load amps [any rpm less then 100% motor rating] the controller sees amps and temperature climbing through the roof, glowing red hot, until the motor comes up to speed. Similar to 'heaters' on a typical #2 motor Allen Bradley motor starter control.
The prop is going to be the same prop with either propulsion system. Foot pounds at ten hp is the same.
In short [excuse the pun] either system works fine. The question remains this--> How many btu's in the bank of batteries? vs. How many btu's in the amount of gasoline carried? <--And that is going to determine how far you travel on the auxiliary power. Amp hours [burning btu's] consumed is entirely up to where the rheostat is set.
Torque [ft/lb] = [5,252 x hp] divided by rpm.
When Boeing flies a loaded 747 across the ocean on one bank of batteries and on one charge, I'll be a believer in massive electric power.
There is a reason why over 200 electric motor car/truck companies have failed since the 1800's.
But what do I know? skip.
I would think that "instant torque" would apply to the pitch and diameter you can use on the prop. Since the diameter is limited I would think that the use of an electric motor would allow for a higher pitched prop that can be used at lower RPM's. The diesel in my 27 does not have much torque at low RPM's so the prop pitch is limited to keep the engine from stalling at low speed. Having just done an engine swap I am guessing that is why Koinonia is curious about props and performance.
Correct-a-mundo. Electric is flat torque; the torque generated is the same at 1 RPM or 10,000 RPM. Thereby the props are generally different.
Electric propulsion is not for crossing oceans, unless you're hybrid (diesel electric or some other variant) to generate the power.
For lake or coastal cruisers, it's ideal; especially if you can shed the power generation responsibility to someone else (major utility) and just recharge at the dock. Same for ocean crossings; the electric propulsion is utilized docking and undocking, not crossing the Med. That's what the sails are for Columbus!
Yep, all electric vehicles are a tough sell. But think of the railroads, which are almost universally hybrid, using diesel-electric. Why? Flat torque, or rather full torque, to get the load going.
There's a 44 footer out there that repowered to hybrid electric on the east coast, and is now in Seattle or Oregon. Their data suggests they used less than 25% of the petrol they would have on the old motor; the generator running at constant efficient RPM was that much more effiicient.
One rpm or 10,000 rpm and the ' Electric is flat torque ' meaning it's the same.
O.K. So? What's that mean exactly?
Certainly not that the prop is going to move the same amount of water at one rpm as it does at 10,000 rpm. At one rpm torque means nothing.
A flat torque to me means " It's the same push per revolution but not the same water displacement. Which is what you need if your going to move a boat through the water.
We are not moving more gallons of water with one rpm as we did at 10,000 rpm.
So the boat's not going to go faster. [ This is exactly why an automotive type automatic gear shifting transmission can not be used on boats. ]
Diesel electric is fine. [Works well on Carnival Cruse Line Mega vessels. They travel 16 foot on one gallon of diesel as related on the Discovery T.V. show.] Yep. Burn diesel fuel oil in an engine at maybe 55%, to turn a generator at 50% to make electricity at to turn an electric motor at 40% to turn a prop with slip of 40%. These are general terms and could be way off. But you get the idea.
Railroads are cool. Each wheel has the contact surface on the rail equal to that of a dime's surface. Which is why you apply air braking before dynamic braking [trying to run the electric motor backwards], unless you want to derail the train, and which is why 'It's hard to stop a train' once she's rolling.
Prop diameter is a function of the hull's size and shape. Pitch is sized to use all the torque available that comes down the shaft. The most efficient prop is one blade. But can't be balanced. Two blades generally need to be of a larger diameter in order to generate enough surface area because they lack pitch. So three blades, after all the tradeoffs are the best choice. Four blades block the other blades. And so it is.
skip.
Guys, what do you do with your Universal when you repower? Is there a big market out there where collectors pay big bucks for 20+ year old 10 hp diesels?
Skip the torque is for handling and pushing a better prop.
Is another essay response in order?
What exactly is a 'Better Prop'?
Better for what?
It's moving X amount of water.
What else can the prop do?
The prop can't handle any more then ten shaft hp.
Inquiring minds need to know.
Your definitions please.
Put the removed Universal/Westerbeke diesel up on Craig's list for sale.
skip.
........ :-\ .........
Mac :P
Any results yet from motoring the boat with the electric engine? Did I get the original description right; you bought the boat new and had them build it with a SolidNav motor? I'd be very interested to hear about your experience!
I'm very interested too!
capt_nemo