Electric Propulsion for 61' Barge

[magician2000]

I am looking into the fesability of powering a 61' barge via electric propulsion.
She is currently only a shell, with 2 stern tubes. Once she has the hold covered I am planning on covering about 50% of the roof with solar. I am currently in Ireland. Her anticipated displacment when complete will be around 45 ton. Typicaly a barge of this size would be powered by a single 120hp diesel, how would I try to equate that to what kind of power I would need out of an electric. Is there any good reference sites out there for info on powering a vessel this size. I have found a lot that cover the 14'-28' range but nothing at the size I am looking to power.

[JonathanCole]

Sure it is possible, but it depends on how slow you want to go. The good thing about a European barge is that it had a large amount of displacement which means it can support the weight of batteries for storing your electrical energy. But the large dispalacement also has a penalty of requiring a lot of energy to move, especially as you increase speed beyond 5 or 6 knots. The best way to utilize electric power would be to design the boat for it. Then you can get the greatest efficiency designed into every level.

However with your barge you could run an internal combustion engine with generator, then you have a hybrid. Just use the generator when the sun isn't enough. Use bio diesel. Also put a few small 500 watt wind generators because often the wind blows through the night when you aren't cruyising and charges your batteries for the next day. This stuff all works, I have been working with it for almost 25 years.

Check out the threads for designing a boat for efficient slow motoring.

I would be happy to help you figure out how to set up your barge if you need it.

Check out this company
http://www.solomontechnologies.com/S...c%20wheel.html
and this example
http://www.solomontechnologies.com/S...stall%202.html

[magician2000]

Jonathan...
Right now I am looking at the feasibility of the project... Starting with a bare hull give me a few advantages... One important one, is I can use my batteries as ballast, and not waste money on iron or concrete to put in the hull to weigh her down... I understand the principle of your energy consumption going up exponentially as your speed increases… I am looking at having a 60’ length at waterline, barge displacing approximately 45 ton… She currently has 2 stern tubes, how do I figure out the best motor HP for the barge… I am planning on covering about 50% of my roof with solar panels… I have heard the main detraction against the wind generators being they are a bit noisy… Granted Ireland does not have the most sun in the world… But I don’t see myself traveling much more than 10 to 15 miles in a day anyway, and as I planning on it for a liveaboard, with no retirement plans for the next 11 years 6 months and 24 days (but who is counting). The plan is to visit all of the towns and villages in Ireland that are on the River Shannon, Royal Canal, and Grand Canal, and then off to Calis, France to go Calis, France to St. Petersburg, Russia… Not sure how long it will take me to get thru France with all the vineyard, and Germany with all the breweries…

[JonathanCole]

Originally Posted by magician2000

Jonathan...
Right now I am looking at the feasibility of the project... Starting with a bare hull give me a few advantages... One important one, is I can use my batteries as ballast, and not waste money on iron or concrete to put in the hull to weigh her down... I understand the principle of your energy consumption going up exponentially as your speed increases… I am looking at having a 60’ length at waterline, barge displacing approximately 45 ton… She currently has 2 stern tubes, how do I figure out the best motor HP for the barge… I am planning on covering about 50% of my roof with solar panels… I have heard the main detraction against the wind generators being they are a bit noisy… Granted Ireland does not have the most sun in the world… But I don’t see myself traveling much more than 10 to 15 miles in a day anyway, and as I planning on it for a liveaboard, with no retirement plans for the next 11 years 6 months and 24 days (but who is counting). The plan is to visit all of the towns and villages in Ireland that are on the River Shannon, Royal Canal, and Grand Canal, and then off to Calis, France to go Calis, France to St. Petersburg, Russia… Not sure how long it will take me to get thru France with all the vineyard, and Germany with all the breweries…

Ok, Batteries weigh about 125 pounds times 6 for 3000 watts of storage at twelve volts. But you will want to be running at higher voltage, probably 48-72 volts. At this voltage range you can get 5 - 10 electric drive horsepower with full torque throughout the rpm range. According to experts this gives you 3-4 times the effective thrust of internal combustion engines of the same HP rating. So a 10 HP electric drive could be equivalent to a 30 hp internal combustion engine. If you have dual stern drive tubes you could run 2 - 10 horsepower electric motors. Of course with a tub like that, it takes a lot to get her going and a lot to slow her down. Most of the time between acceleration and deceleration, you probably only use half your HP capacity. So the more batteries, the better (Flooded lead acid batteries have the longest life of 10-15 years if used properly). You will also need controls for the motors. These pulse width modulation controllers chop the current into on-off segments, so you only draw the energy you need.

If you have, say, 6 feet by 30 feet of solar electric panels, that will give you about 1800 watts of power (rule of thumb - 10 watts/sq.ft.). That's only about 2.5 horsepower, so you will need to rely on other forms of battery charging as well, such as an onboard generator and an industrial sized charger (which can also be plugged into the mains when docked), wind generators, etc. Wind generators can be turned off and only used when you are not on board. They can be mounted in rubber bushings to limit vibration. They can be mounted in a duct to limit prop noise.

[yokebutt]

Magician,

For small boats there is a fair bit of equipment readily available, mainly thanks to electric carts and that sort of thing. For bigger things, diesel-electric tugboats and the like, there are also ready solutions.

But, You're kind of in-between size-wise, personally, I'd start by investigating the possibiliy of using multiple Lemco motors, they're about as efficient as you can get.

Yoke.