Ned,
You should look up a Carver Santa Cruz 28. As a cabin cruiser, the challenge would be to build anything that provides the same interior space and carrying capacity in a "light weight, length to beam ratios of 4 or 5, and flat or low deadrise bottom" design. That's kind of like suggesting someone trade in their company's utility box truck for a compact car to get better mileage. Yes, they would get better mileage, but the little car would be completely inappropriate for the job. Even on the links that you suggested, the simliar sized cabin cruisers call for 150+ hp engines with warnings not to underpower the boat.
Everyone here knows that I am a huge proponent of electric conversions, but only where it makes sense. Electric drive is not universal answer, not in cars, not in boats, not in scooters, not in chain saws, etc. It can be a very good answer, if matched to the use case, but ICE is often a better answer. My 30' ketch is electric, my 27' trimaran got a new 4-stroke outboard.
That said, I don't think that this size cabin cruiser is a good candidate for an electric conversion. Going electric in this type of boat would be too much of a compromise for me.
Fair winds and smooth seas,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Ned Farinholt <nedfarinholt@...> wrote:
>
> Paul,
> In re planing electric boats, the solution if you want to plane for any distance or length of time is to start with a much lighter hull than you are likely to find on a "conversion". Starting with a hull that weighs over 1000 lbs makes it very difficult. We have achieved very high efficiencies in motors, controllers, transmissions, and props. There is not much room for improvement in these areas. That leaves us with displacement and hull design. If you study hull design options I think you will come to two possibilities. One is to follow the approach of sailing catamarans with their long thin hulls that overcome displacement hull speed limitations with a high aspect ratio of length to beam but of course these are not "planing." The other is to refer back to the designs of the 1920's when 5 to 20 hp outboards were just becoming available. There are a number of very fine semi-displacement and planing designs available. The dominant characteristics of all of these are light weight, length to beam ratios of 4 or 5, and flat or low deadrise bottoms. See, for example, plans by Mower http://www.dngoodchild.com and Atkins http://www.atkinboatplans.com.
> I built a 250 lb hull, 19' x 4.5', with 225 lb of LiFePO4 batteries, 60v x 160 Ah, and a Torqeedo 4R outboard. I did 11.25 mph for 24 miles. See http://www.youtube.com/watch?v=7nsjpqWHWpo
> I hope this is helpful.
> Keep it light!
> Ned
>
> > > ----- Original Message -----
> > > From: cPAUL
> > > To: electricboats@yahoogroups.com
> > > Sent: Saturday, March 23, 2013 2:43 PM
> > > Subject: [Electric Boats] Help me decide the most appropriate components...
> > >
> > >
> > > Hi and thanks for reading this.... I recently aquired a 28 ft Carver Santa Cruz. It has dual 220 hp gas engines I will be removing. I plan on using common parts," as low cost as possible. I have some electrical experience, and will have no problem doing a clean install, does any one have any suggestions for my layout and which parts I should use? I will also have solar cells, wind generators. I was also wondering on the use of 12v altinators being powered on by the prop shaft. The boats total weight with the two motors is approx. 10,500 lbs. does any one have any helpful knowledge or advice??
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> >
> >
>
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