Please keep us posted on the results, and your satisfaction on this.   There are a lot of folks who are interested in electric propulsion.   I work on diesels all the time, and consider them extremely reliable dependable long life engines.   Keep clean fuel in them and minimal maintenance, and they never let you down.    I do have huge issues with marine installations with raw water, or heat exchanger systems, especially the former.   I just did a major rebuild on an Isuzu 4BG with slightly over 22000 original hours on it.... yes that is twenty two thousand!   It had regular maintenance, and I had an injector pump rebuilt on it a few years back.  It was still running strong, but I didn't like what the oil pressure was doing.  Internally it was actually in quite good shape, but the relief spring in the oil pump was acting up.   An expensive engine to work on, but considering the hours, the owner couldn't complain...

Just a few numbers.....  one horsepower is approximately equal to .75 KW   or 750 watts.   2000 watts = a theoretical 2.66 horsepower, but one needs to factor in electric motor efficiency, which maxes out at 85%, and ranges from 70% to 85% in the real world.   Assuming 80% efficiency, your real world  horsepower will come in about 2.13 at the shaft.    That makes it extremely important to have an efficient prop.   Prop diameter and optimal pitch for the speed you are cruising at are critical.   

     To achieve your 10 horsepower should require 9375 watts factoring in the efficiency of 0%    At 48 volts, that is 195 amps, which is about what an automotive starter draws.  You will need a LOT of batteries to get much performance out of this system.   Do not depend on running from the generator.   Run from the batteries and supplement the charging system from the generator.  

      My pencil says it's impractical.   If I sound like a skeptic....  It's because I am.    But I'm a skeptic who would love to be proven wrong.   I look forward to owning an electric vehicle or boat someday, but I've learned the hard way not to be an early adopter.   I'm thankful that there are people who are, otherwise technology would not move forward.  I  have an intense dislike for fast talking salesmen selling pie in the sky... but this is a SAIL boat.

     Please excuse my negativity..... It is not really  meant that way.  Pioneers like yourself blaze the way for those of us who follow later and benefit from what you learn.

                                                     H.W.

Jim wrote:

[...] I intend to buy a Honda EU2200i portable generator, fitted with a three-fuel adapter so it can be run on gasoline, propane of natural gas. According to Electric Yacht, Hobbit can be propelled by a 2Kw generator at 3 knots in calm water, indefinitely. Essentially, we are looking at a hybrid boat [...]

Hi Jim,

I will be looking forward to an update on how well you like this solution. I have been thinking about more or less the same system for a few years now.

I see that the generator you are considering is an inverter generator. I think this means electricity is generated as DC and then converted to AC with electronics insider the generator.

Does it provide a full-power DC output that can drive the motor directly? I am wondering if you will you need to go from fuel to AC and then back to DC with a power supply or battery charger.