Subject: [harryproa] Re: Electric drive for Harryproa
From: "Tim Barker" <>
Date: 4/4/2008, 8:46 PM

--- In, "Rob Denney" <harryproa@...>
Hi Rob
As you know we discussed the possability of using the tender on a
beam attached pivot to provide some propulsion on the scaled down
charter proa, Ive considered lots of variations and one possability
ive been considering after deeming the electric drive too expensive
and complex for me (think its a great idea but im obsessing about
simplicity) ,is the use of a suitablt petrol or diesel engine mounted
over beside the lw hull thereby taking advantage of the seperation of
the pleasure and buisness area's (which hasnt been mentioned as a
proa plus when talking about propulpulsion). The use of a gearbox and
drop down ,pivoting engine shaft assy would allow the use of a big
efficient prop with a kick up skeg mounted below, a much cheaper
proposition and well within the abilities of the owner builder to set
up, requiring minimal specialist knowledge and over the shelf parts.

I have even entertained the possability of using "normal " liquid to
air heat exchangers a la car radiator to simplify piping and keep
expence down.
Part of the reason for this idea is desire to be able to charge scuba
tanks away from civilization, i would set up a simple belt drive
compressor and clutch to allow the propulsion engine to charge scuba
tanks, a natural progression of this would also be a nice fat
altenator , other variation that might appeal to others are engine
driven watermaker/deckwash hydraulic bow thruster etc etc etc .

To my mind the home builder could save some serious money and have a
multi use system that would be easy to get parts for and be easy to
work on for the mechanically challenged.

Again just an idea to kick around but worth a thought.

Cheers Tim

> > On Thu, Apr 3, 2008 at 11:29 PM, George Kuck <chesapeake410@...>
> > >
> > >
> > >
> > >
> > >
> > >
> > > Hello Rob
> > >
> > > Will you be designing beam mounted rudders for the 12 m
Harryproa ? I do
> > > like the aesthetics of the boat with rudders on the hull but
if it works
> > > better on the beam then that will have to be done.
> >
> > They are designed and ready to go. Just waiting for the full
> > tests on Blind Date (they broke a test shaft last week. Took 15
> > tons!). The visual and drag impacts are less than on the hull
> > mounted ones, the steering is much easier (only one wheel, or two
> > short tiller extensions) the weight is lower and they are
easier to
> > build and to lift.
> >
> > Do you know anything
> > > about the "E-Jet" ? The web sight did not seem to have much
details (in
> > > English anyway) and I believe I have heard negative things
about the company
> > > recently in the electric boat forum. It may be that it is
only a concept
> > > motor design at this time and not yet in production, but it
does look like a
> > > neat motor. I wonder how expensive it is and when it will be
available ?
> > > The Re-E-Power looks good and it is in production in the US so
the company
> > > would be easier for me to deal with.
> >
> > I have written to E Jet, nothing back yet, will let you know.
Re E
> > Power sound like a really good crowd to deal with, as are the
> > Motion people in South Africa. The whole electric boat thing is
> > moving ahead in leaps and bounds. This thread is moving me
nicely up
> > the learning curve, so please keep it going.
> >
> > JT, put one electric motor on one rudder and lock it. Put the
> > autopilot on the other rudder.
> >
> > > Have a nice day and good sailing,
> >
> > Ta, you too.
> >
> > Regards,
> >
> > Rob

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